Liver cancer is a rare malignancy in children and adolescents and is divided into the following two major histological subgroups:
Other less common histologies include the following:
Historically, four major study groups have performed prospective clinical trials in children with liver tumors: The International Childhood Liver Tumors Strategy Group (previously known as Société Internationale d’Oncologie Pédiatrique–Epithelial Liver Tumor Study Group [SIOPEL]), the Gesellschaft für Pädiatrische Onkologie und Hämatologie (Society for Paediatric Oncology and Haematology [GPOH]), the Japanese Study Group for Pediatric Liver Tumors (JPLT), and the Children's Oncology Group (COG), including its predecessor groups the Children's Cancer Group (CCG) and Pediatric Oncology Group (POG). These groups historically had disparate risk stratification categories, data elements that were monitored, and pathological and radiological definitions, making it difficult to compare outcomes across continents.
A collaborative effort among all four study groups collated their disparate data into a unified database called the Children's Hepatic Tumor International Collaboration (CHIC). The CHIC group analyzed clinical features and outcomes in a database that included 1,605 patients with hepatoblastoma treated in eight separate multicenter clinical trials, with central review of all tumor imaging and histological details.[1] Patients who underwent orthotopic liver transplant were also included.[2]
Liver tumors are rare in children. A definitive pathological diagnosis may be challenging because of the rarity of the tumor and the lack of a universal classification system before the Children's Hepatic Tumor International Collaboration (CHIC) harmonization efforts. Systematic central histopathological review of these tumors, performed as part of pediatric collaborative therapeutic protocols, has allowed the identification of histological subtypes with distinct clinical associations.
The Children's Oncology Group (COG) Liver Tumor Committee sponsored an International Pathology Symposium in 2011 to discuss the histopathology and classification of pediatric liver tumors (hepatoblastoma, in particular) and develop an International Pediatric Liver Tumors Consensus Classification that would be required for international collaborative projects. The results were published in 2014.[1] In a post-hoc expert consensus review of 599 hepatoblastoma cases treated across five multicenter trials, 570 (95%) were validated and independently re-confirmed to be hepatoblastoma using the CHIC pathology guidelines.[2] This standardized, clinically meaningful classification has allowed the integration of new biological parameters and tumor genetics within a common pathological language to help improve future patient management and outcomes.
For information about the histology of each childhood liver cancer subtype, see the following sections:
A main treatment goal for children and adolescents with liver cancer is surgical extirpation of the primary tumor. Risk grouping depends heavily on factors determined by imaging that are related to safe surgical resection of the tumor, as well as the PRETEXT grouping. These imaging findings include the section or sections of the liver that are involved with the tumor and additional findings, called annotation factors, that impact surgical decision making and prognosis.
Risk stratification of children and adolescents with liver cancer involves the use of high-quality, cross-sectional imaging. Three-phase computed tomography scanning (noncontrast, arterial, and venous) or magnetic resonance imaging (MRI) with contrast agents are used. MRI with gadoxetate disodium, a gadolinium-based agent that is preferentially taken up and excreted by hepatocytes, is being used with increased frequency and may improve detection of multifocal disease.[1]
The imaging grouping systems used to radiologically define the extent of liver involvement by the tumor are designated as the following:
Major multicenter trial groups use PRETEXT as a central component of risk stratification schemes that guide treatment of hepatoblastoma. PRETEXT is based on the Couinaud eight-segment anatomical structure of the liver using cross-sectional imaging.
The PRETEXT system divides the liver into four parts, called sections. The left lobe of the liver consists of a lateral section (Couinaud segments I, II, and III) and a medial section (segment IV), whereas the right lobe consists of an anterior section (segments V and VIII) and a posterior section (segments VI and VII) (see Figure 1). PRETEXT groups were devised by the Société Internationale d’Oncologie Pédiatrique–Epithelial Liver Tumor Study Group (SIOPEL) for their first trial, SIOPEL-1,[2] and revised for the SIOPEL-3 trial in 2007.[3]
PRETEXT group assignment I, II, III, or IV is determined by the number of uninvolved sections of the liver. PRETEXT is further described by annotation factors. Annotation factors include findings that are important for surgical management and evidence of tumor extension beyond the hepatic parenchyma of the major sections, including metastatic disease. For detailed descriptions of the PRETEXT groups, see Table 1. For descriptions of the annotation factors, see Table 2.
Annotation factors identify the extent of tumor involvement of the major vessels and its effect on venous inflow and outflow. These factors provide critical knowledge for the surgeon and can affect surgical outcomes. At one time, definitions of gross vascular involvement used by the Children's Oncology Group (COG) and major liver surgery centers in the United States differed from those used by SIOPEL and in Europe. These differences have been resolved, and the new definitions are being used in an international trial.[4]
Although PRETEXT can be used to predict tumor resectability, it has limitations. It can be difficult to distinguish real invasion beyond the anatomical border of a given hepatic section from compression and displacement by the tumor, especially at diagnosis. Additionally, it can be difficult to distinguish between vessel encroachment and involvement, particularly if imaging is inadequate. The PRETEXT group assignment has a moderate degree of interobserver variability. In a report using data from the SIOPEL-1 study, the preoperative PRETEXT group aligned with postoperative pathological findings only 51% of the time, with overstaging in 37% of patients and understaging in 12% of patients.[5]
Because distinguishing PRETEXT group assignment is difficult, central review of imaging is critical and is generally performed in all major clinical trials. For patients not enrolled in clinical trials, expert radiological review should be considered in questionable cases in which the PRETEXT group assignment affects choice of treatment.
PRETEXT and POSTTEXT Groups | Definition | Image | |
---|---|---|---|
aAdapted from Roebuck et al.[3] | |||
I | One section involved; three adjoining sections are tumor free. | ||
II | One or two sections involved; two adjoining sections are tumor free. | ||
III | Two or three sections involved; one adjoining section is tumor free. | ||
IV | Four sections involved. |
Annotation Factors | Definition | ||
---|---|---|---|
CT = computed tomography; MRI = magnetic resonance imaging; HU = Hounsfield unit. | |||
aAdapted from Roebuck et al.[3] | |||
bAdditional details describing the annotation factors have been published.[4] | |||
Vb | Venous involvement: Vascular involvement of the retrohepatic vena cava or involvement of all three major hepatic veins (right, middle, and left). | ||
V0 | Tumor within 1 cm. | ||
V1 | Tumor abutting. | ||
V2 | Tumor compressing or distorting. | ||
V3 | Tumor ingrowth, encasement, or thrombus. | ||
Pb | Portal involvement: Vascular involvement of the main portal vein and/or both right and left portal veins. | ||
P0 | Tumor within 1 cm. | ||
P1 | Tumor abutting the main portal vein, the right and left portal veins, or the portal vein bifurcation. | ||
P2 | Tumor compressing the main portal vein, the right and left portal veins, or the portal vein bifurcation. | ||
P3 | Tumor ingrowth, encasement (>50% or >180 degrees), or intravascular thrombus within the main portal vein, the right and left portal veins, or the portal vein bifurcation. | ||
Eb | Extrahepatic spread of disease. Any one of the following criteria is met: | ||
E1 | Tumor crosses boundaries/tissue planes. | ||
E2 | Tumor is surrounded by normal tissue more than 180 degrees. | ||
E3 | Peritoneal nodules (not lymph nodes) are present so that there is at least one nodule measuring ≥10 mm or at least two nodules measuring ≥5 mm. | ||
Mb | Distant metastases. Any one of the following criteria is met: | ||
M1 | One noncalcified pulmonary nodule ≥5 mm in diameter. | ||
M2 | Two or more noncalcified pulmonary nodules, each ≥3 mm in diameter. | ||
M3 | Pathologically proven metastatic disease. | ||
C | Tumor involving the caudate. | ||
F | Multifocality. Two or more discrete hepatic tumors with normal intervening liver tissue. | ||
Nb | Lymph node metastases. Any one of the following criteria is met: | ||
N1 | Lymph node with short-axis diameter of >1 cm. | ||
N2 | Portocaval lymph node with short-axis diameter >1.5 cm. | ||
N3 | Spherical lymph node shape with loss of fatty hilum. | ||
Rb | Tumor rupture. Free fluid in the abdomen or pelvis with one or more of the following findings of hemorrhage: | ||
R1 | Internal complexity/septations within fluid. | ||
R2 | High-density fluid on CT (>25 HU). | ||
R3 | Imaging characteristics of blood or blood degradation products on MRI. | ||
R4 | Heterogeneous fluid on ultrasound with echogenic debris. | ||
R5 | Visible defect in tumor capsule OR tumor cells are present within the peritoneal fluid OR rupture diagnosed pathologically in patients who have received an upfront resection. |
The POSTTEXT group is determined after patients receive chemotherapy. The greatest chemotherapy response, measured as decreases in tumor size and alpha-fetoprotein (AFP) level, occurs after the first two cycles of chemotherapy.[6,7] A study that evaluated surgical resectability after two versus four cycles of chemotherapy showed that many tumors may be resectable after two cycles.[6]
The COG/Evans staging system, based on operative findings and surgical resectability, was used for many years in the United States to group and determine treatment for children with liver cancer (see Table 3).[8-10] Currently, other risk stratification systems are predominantly used to classify patients and determine treatment strategy, although the Paediatric Hepatic International Tumour Trial (PHITT) uses the Evans system for patients with hepatocellular carcinoma. For more information, see Table 5.
Evans Surgical Stage | Definition |
---|---|
Stage I | The tumor is completely resected. |
Stage II | Microscopic residual tumor remains after resection. |
Stage III | There are no distant metastases and at least one of the following is true: (1) the tumor is either unresectable or the tumor is resected with gross residual tumor; (2) there are positive extrahepatic lymph nodes. |
Stage IV | There is distant metastasis, regardless of the extent of liver involvement. |
Many of the improvements in survival in childhood cancer have been made using new therapies that have attempted to improve on the best available, accepted therapy. Clinical trials in pediatrics are designed to compare potentially better therapy with therapy that is currently accepted as standard. This comparison may be done in a randomized study of two treatment arms or by evaluating a single new treatment and comparing the results with those previously obtained with standard therapy.
Because of the relative rarity of cancer in children, all children with liver cancer should be considered for a clinical trial if available. Treatment planning by a multidisciplinary team of cancer specialists with experience treating tumors of childhood is required to determine and implement optimal treatment.[1]
Historically, complete surgical resection of the primary tumor has been essential for cure of malignant liver tumors in children.[2-6]; [7][Level of evidence C1] This approach continues to be the goal of definitive surgical procedures, which are often combined with chemotherapy. The surgeon performs a highly sophisticated liver resection in children and adolescents with primary liver tumors after the diagnosis is confirmed by pathological investigation of intraoperative frozen sections. While complete surgical resection is important for all liver tumors, it is especially important for hepatocellular carcinoma because curative chemotherapy is not available. In patients with advanced hepatoblastoma, postoperative complications are associated with worsened overall survival (OS).[8]
The three surgical options to treat primary pediatric liver cancer include the following:
The decision on which surgical approach to use (e.g., partial hepatectomy, extended resection, or transplant) depends on many factors, including the following:
Timing of the surgical approach is critical. Surgeons who have experience performing pediatric liver resections and transplants are involved early in the decision-making process to determine optimal timing and extent of resection.
Early involvement, preferably at diagnosis, with an experienced pediatric liver surgeon is especially important in patients with PRETEXT group III or IV or involvement of major liver vessels (positive annotation factors V [venous] or P [portal]).[9] Although vascular involvement was initially thought to be a contraindication to resection, experienced liver surgeons are sometimes able to successfully resect the tumor and avoid performing a transplant.[10-12]; [13][Level of evidence C1] Patients with vascular involvement and tumors that have been deemed nonresectable by the pediatric surgical expert should be referred to a transplant center to avoid unnecessary delays in evaluation and listing for transplant.
Intraoperative ultrasonography may result in further delineation of tumor extent and location and can affect intraoperative management.[14] Preoperative infusion of indocyanine green, a fluoroactive agent that is concentrated in the liver and retained by abnormal liver tumors, has also been used to provide visual intraoperative guidance to locate the tumor and assess proximity to surgical margins.[15,16]
If the tumor is determined to be unresectable, measures to reduce the tumor size to make a complete surgical resection possible need to be considered. These measures include preoperative intravenous chemotherapy, transarterial chemotherapy, or transarterial radioactive therapy. These efforts must be carefully coordinated with the surgical team to facilitate planning of resection. Prolonged chemotherapy can lead to unnecessary delays and, in rare cases, tumor progression. If the tumor can be completely excised by an experienced surgical team, less postoperative chemotherapy may be needed. Incomplete resection must be avoided because patients who undergo rescue transplants of incompletely resected tumors have an inferior outcome, compared with patients who undergo transplant as the primary surgical therapy.[17][Level of evidence C1] Accomplishing the appropriate surgery at resection is critical.
The approach taken by the Children's Oncology Group (COG) in North American clinical trials is to perform surgery initially when a complete resection can be done with a simple, negative-margin hemihepatectomy. The COG AHEP0731 (NCT00980460) trial studied the use of PRETEXT and POSTTEXT to determine the optimal approach and timing of surgery. POSTTEXT imaging grouping was performed after two and four cycles of chemotherapy to determine the optimal time for definitive surgery.[6,18] For more information, see the Tumor Stratification by Imaging section.
Liver transplants have been associated with significant success in the treatment of children with unresectable hepatic tumors.[19]; [20-22][Level of evidence C1] A review of the world experience has documented a posttransplant survival rate of 70% to 80% for children with hepatoblastomas.[17,23-25] Intravenous vascular invasion, positive lymph nodes, and contiguous extrahepatic spread did not have significant adverse effects on outcome. Adjuvant chemotherapy after transplant may decrease the risk of tumor recurrence, but its use has not been studied definitively in a randomized clinical trial.[26]
Evidence (orthotopic liver transplant):
Application of the Milan criteria for UNOS selection of recipients of deceased donor livers is controversial.[31,32] The Milan criteria for liver transplant are directed toward adults with cirrhosis and hepatocellular carcinoma. The criteria do not apply to children and adolescents with hepatocellular carcinoma, especially those without cirrhosis.
Cirrhosis is an underlying risk factor for the development of hepatocellular carcinoma in children who suffer from certain diseases or conditions. These diseases include perinatally acquired hepatitis B, hepatorenal tyrosinemia, progressive familial intrahepatic cholestasis, glycogen storage disease, Alagille syndrome, and other conditions. Improvements in screening methodology have allowed for earlier identification and treatment of some of these conditions, as well as monitoring for development of hepatocellular carcinoma. Nevertheless, because of the poor prognosis of patients with hepatocellular carcinoma, liver transplant should be considered for diseases or conditions that have resulted in early findings of cirrhosis, before the development of liver failure or malignancy.[33]
Living-donor liver transplant for hepatic malignancy is more common in children than adults, and the outcome is similar to those undergoing cadaveric liver transplant.[34,35] In patients with hepatocellular carcinoma, gross vascular invasion, distant metastases, lymph node involvement, tumor size, and male sex were significant risk factors for recurrence. In one report, 33 patients with hepatoblastoma and 10 patients with hepatocellular carcinoma were treated with living-donor liver transplants. For the hepatoblastoma patients, the 5-year OS rate was 87.4%, and the EFS rate was 75.8%. The 5-year OS and EFS rates were 75.4% for the patients with hepatocellular carcinoma. The presence of renal vein invasion was associated with an increased incidence of recurrence and death (P = .28).[36][Level of evidence C1]
Surgical resection of metastatic disease is often recommended, but the rate of cure in children with hepatoblastoma has not been fully determined. Resection of metastases may be done for areas of locally invasive disease (e.g., diaphragm) and isolated brain metastases. Resection of pulmonary metastases should be considered if the number of metastases is limited.[37-40] In a North American study of 38 patients who presented with pulmonary metastases at diagnosis, only nine patients underwent surgical resection. The timing of pulmonary resection in relation to definitive resection of the primary tumor varied (two patients before, five patients simultaneously, and two patients after primary resection). Eight of the nine patients survived. Of 20 children with relapse restricted to the lungs, all patients received salvage chemotherapy, 8 patients had a thoracotomy and pulmonary metastasectomy, and 5 patients had a thoracotomy and biopsy. Among the 13 patients who had surgery, only 4 were long-term survivors, 2 of whom presented with stage I disease and 2 of whom presented with stage IV disease.[39]
Radiofrequency ablation has also been used to treat oligometastatic hepatoblastoma when patients prefer to avoid surgical metastasectomy.[41][Level of evidence C1]
Chemotherapy regimens used in the treatment of hepatoblastoma and hepatocellular carcinoma are described in their respective sections. Chemotherapy has been much more successful in the treatment of hepatoblastoma than in the treatment of hepatocellular carcinoma.[6,28,42] For more information, see the sections on Treatment of Hepatoblastoma and Treatment of Hepatocellular Carcinoma.
The standard of care in the United States is preoperative chemotherapy when the tumor is unresectable and postoperative chemotherapy after complete resection, even if preoperative chemotherapy has already been given.[43] Preoperative chemotherapy has been shown to benefit children with hepatoblastoma. However, postoperative chemotherapy after definitive surgical resection or liver transplant has not been investigated in a randomized fashion.
Radiation therapy, even in combination with chemotherapy, has not cured children with unresectable hepatic tumors. A study of 154 patients with hepatoblastoma showed that radiation therapy and/or second resection of positive margins may not be necessary in some patients with incompletely resected hepatoblastoma and microscopic residual tumor.[44] Although there is no standard indication, radiation therapy may have a role in the management of patients with incompletely resected hepatoblastomas.[45] Stereotactic body radiation therapy is a safe and effective alternative treatment that has been successfully used in adult patients with hepatocellular carcinoma who are unable to undergo liver ablation/resection.[46] This highly conformal radiotherapeutic technique, when available, may be considered on an individual basis in children with hepatocellular carcinoma.
Other treatment approaches include the following:
Cancer in children and adolescents is rare, although the overall incidence has slowly increased since 1975.[1] Children and adolescents with cancer should be referred to medical centers that have a multidisciplinary team of cancer specialists with experience treating the cancers that occur during childhood and adolescence. This multidisciplinary team approach incorporates the skills of the following pediatric specialists and others to ensure that children receive treatment, supportive care, and rehabilitation to achieve optimal survival and quality of life:
For specific information about supportive care for children and adolescents with cancer, see the summaries on Supportive and Palliative Care.
The American Academy of Pediatrics has outlined guidelines for pediatric cancer centers and their role in the treatment of children and adolescents with cancer.[2] At these centers, clinical trials are available for most types of cancer that occur in children and adolescents, and the opportunity to participate is offered to most patients and their families. Clinical trials for children and adolescents diagnosed with cancer are generally designed to compare potentially better therapy with current standard therapy. Other types of clinical trials test novel therapies when there is no standard therapy for a cancer diagnosis. Most of the progress in identifying curative therapies for childhood cancers has been achieved through clinical trials. Information about ongoing clinical trials is available from the NCI website.
Dramatic improvements in survival have been achieved for children and adolescents with cancer. Between 1975 and 2020, childhood cancer mortality decreased by more than 50%.[3-5] Childhood and adolescent cancer survivors require close monitoring because side effects of cancer therapy may persist or develop months or years after treatment. For specific information about the incidence, type, and monitoring of late effects in childhood and adolescent cancer survivors, see Late Effects of Treatment for Childhood Cancer.
The annual incidence of hepatoblastoma in the United States has increased (more than doubled), from 0.8 (1975–1983) to 2.3 (2020) cases per 1 million children aged 19 years and younger.[1-3] The cause for this increase is unknown, but the improved survival of premature infants with very low birth weight, which is known to be associated with hepatoblastoma, may contribute.[4] In Japan, the risk of hepatoblastoma in children who weighed less than 1,000 g at birth is 15 times the risk in children with normal birth weight.[5] Other data have confirmed the high incidence of hepatoblastoma in premature infants with very low birth weight.[6] Attempts to identify factors resulting from treatment of infants born prematurely have not revealed any suggestive causation of the increased incidence of hepatoblastoma.[4]
The age of onset of liver cancer in children is related to tumor histology. Hepatoblastomas usually occur before the age of 3 years, and approximately 90% of malignant liver tumors in children aged 4 years and younger are hepatoblastomas.[7]
Conditions associated with an increased risk of hepatoblastoma are described in Table 4.
Associated Disorder | Clinical Findings |
---|---|
Aicardi syndrome [8] | For more information, see the Aicardi syndrome section. |
Beckwith-Wiedemann syndrome [9,10] | For more information, see the Beckwith-Wiedemann syndrome and hemihyperplasia section. |
Familial adenomatous polyposis [11-13] | For more information, see the Familial adenomatous polyposis section. |
Glycogen storage diseases I–IV [14] | Symptoms vary by individual disorder. |
Low-birth-weight infants [4-6,15,16] | Preterm and small-for-gestation-age neonates. |
Simpson-Golabi-Behmel syndrome [17] | Macroglossia, macrosomia, renal and skeletal abnormalities, and increased risk of Wilms tumor. |
Trisomy 18, other trisomies [18] | Trisomy 18: Microcephaly and micrognathia, clenched fists with overlapping fingers, and failure to thrive. Most patients (>90%) die in the first year of life. |
Aicardi syndrome is presumed to be an X-linked condition reported exclusively in females, leading to the hypothesis that an altered gene on the X chromosome causes lethality in males. The syndrome is classically defined as agenesis of the corpus callosum, chorioretinal lacunae, and infantile spasms, with a characteristic facies. Additional brain, eye, and costovertebral defects are often found.[8]
The incidence of hepatoblastoma increases 1,000-fold to 10,000-fold in infants and children with Beckwith-Wiedemann syndrome.[10,19] The risk of hepatoblastoma also increases in patients with hemihyperplasia, previously termed hemihypertrophy, a condition that results in asymmetry between the right and left side of the body when a body part grows faster than normal.[20,21]
Beckwith-Wiedemann syndrome is most commonly caused by epigenetic changes and is sporadic. The syndrome may also be caused by genetic variants and be familial. Either mechanism can be associated with an increased incidence of embryonal tumors, including Wilms tumor and hepatoblastoma.[10] The expression of both IGFR2 alleles and ensuing increased expression of insulin-like growth factor 2 (IGF-2) has been implicated in the macrosomia and embryonal tumors seen in patients with Beckwith-Wiedemann syndrome.[10,22] The types of embryonal tumors associated with sporadic Beckwith-Wiedemann syndrome have frequently undergone somatic changes in the Beckwith-Wiedemann syndrome locus and IGF-2.[23,24] The genetics of tumors in children with hemihyperplasia have not been clearly defined.
To detect abdominal malignancies at an early stage, all children with Beckwith-Wiedemann syndrome or isolated hemihyperplasia undergo regular screening for multiple tumor types by abdominal ultrasonography.[21] Screening using alpha-fetoprotein (AFP) levels has also been quite helpful in the early detection of hepatoblastoma in these children.[25] Because hepatoblastomas that are discovered early are small, treatment may minimize the use of adjuvant therapy after surgery.[19] However, a careful compilation of published data on 1,370 children with (epi)genotyped Beckwith-Wiedemann syndrome demonstrated that the prevalence of hepatoblastoma was 4.7% in those with Beckwith-Wiedemann syndrome caused by chromosome 11p15 paternal uniparental disomy, less than 1% in the two types of alteration in imprinting control regions, and absent in CDKN1C variants.[26] The authors recommended that only children with Beckwith-Wiedemann syndrome caused by uniparental disomy be screened for hepatoblastoma using abdominal ultrasonography and AFP levels every 3 months from age 3 months to 5 years.
Hepatoblastoma is associated with familial adenomatous polyposis (FAP). Children in families that carry the APC gene have an 800-fold increased risk of hepatoblastoma. Screening for hepatoblastoma in members of families with FAP using ultrasonography and AFP levels is controversial because hepatoblastoma has been reported to occur in less than 1% of this group.[11-13,27] However, one study of 50 consecutive children with apparent sporadic hepatoblastoma reported that five children (10%) had APC germline variants.[27]
Current evidence cannot rule out the possibility that predisposition to hepatoblastoma may be limited to a specific subset of APC variants. Another study of children with hepatoblastoma found a predominance of the variant in the 5' region of the gene, but some patients had variants closer to the 3' region.[28] This preliminary study provides some evidence that screening children with hepatoblastoma for APC variants and colon cancer may be appropriate.
In the absence of APC germline variants, childhood hepatoblastomas do not have somatic variants in the APC gene. However, hepatoblastomas frequently have variants in the CTNNB1 gene, whose function is closely related to APC.[29]
An American Association for Cancer Research publication suggested that all children with genetic syndromes that lead to a risk of 1% or greater for developing hepatoblastoma undergo screening. This group includes patients with Beckwith-Wiedemann syndrome, hemihyperplasia, Simpson-Golabi-Behmel syndrome, and trisomy 18 syndrome. Screening is by abdominal ultrasonography and AFP determination every 3 months from birth (or diagnosis) through the fourth birthday, which will identify 90% to 95% of hepatoblastomas that develop in these children.[30]
Genomic findings related to hepatoblastoma include the following:
Gene expression and epigenetic profiling have been used to identify biological subtypes of hepatoblastoma and to evaluate the prognostic significance of these subtypes.[33,36,37,40]
Delineating the clinical applications of these genomic, transcriptomic, and epigenomic profiling methods for the risk classification of patients with hepatoblastoma will require independent validation, which is one of the objectives of the Paediatric Hepatic International Tumour Trial (PHITT [NCT03017326]).
A biopsy is always indicated to confirm the diagnosis of a pediatric liver tumor, except in the following circumstances:
The AFP and beta-hCG tumor markers are helpful in the diagnosis and management of liver tumors. Although AFP is elevated in most children with hepatic malignancies, it is not pathognomonic for a malignant liver tumor.[42] The AFP level can be elevated with either a benign tumor or a malignant solid tumor. Markedly elevated AFP not caused by the tumor is normal in neonates and steadily falls after birth. The half-life of AFP is 5 to 7 days, and by age 1 year, it should be in the reference range, less than 10 ng/mL.[43,44] Beta-hCG levels may also be elevated in children with hepatoblastoma or hepatocellular carcinoma, which may result in isosexual precocity in boys.[45,46]
The 5-year overall survival (OS) rate for children with hepatoblastoma is 70%.[47,48] Neonates with hepatoblastoma have outcomes comparable to those of older children up to age 5 years.[49]
Survival rates at 5 years, unrelated to annotation factors, were found to be the following:
When each annotation factor was examined separately, regardless of the PRETEXT group or other annotation factors, the 5-year OS rates were found to be the following:
For more information about PRETEXT grouping and annotation factors, see the PRETEXT and POSTTEXT Group Definitions section.
Hepatoblastoma prognosis by Evans surgical stage. Current study protocols use the PRETEXT staging for prognosis. The prognosis, based on Evans stage, is listed below. For more information, see the Evans Surgical Staging for Childhood Liver Cancer section.
Approximately 20% to 30% of children with hepatoblastoma have stage I or II disease. Prognosis varies depending on the subtype of hepatoblastoma:
Approximately 50% to 70% of children with hepatoblastoma have stage III disease. The 3- to 5-year OS rate for these children is less than 70%.[50,51]
Approximately 10% to 20% of children with hepatoblastoma have stage IV disease. The 3- to 5-year OS rate for these children varies widely, from 20% to approximately 60%, based on published reports.[50,51,54-57] Postsurgical stage IV is equivalent to any PRETEXT group with annotation factor M.[58-60]
Individual childhood cancer study groups have attempted to define the relative importance of a variety of prognostic factors present at diagnosis and in response to therapy.[61,62] The CHIC study group retrospectively combined data from eight clinical trials (N = 1,605) conducted between 1988 and 2010. They published a univariate analysis of the effect of clinical prognostic factors present at the time of diagnosis on event-free survival (EFS).[58,63] The analysis confirmed many of the statistically significant adverse factors described below:[58]
In contrast, in the SIOPEL-2 and -3 studies, infants younger than 6 months had PRETEXT group, annotation factors, and outcomes similar to those of older children undergoing the same treatment.[65][Level of evidence C1]
In the CHIC study, sex, prematurity, birth weight, and Beckwith-Wiedemann syndrome had no effect on EFS.[58]
A multivariate analysis of these prognostic factors was published to help develop a new risk group classification for hepatoblastoma.[63] This classification was used to generate a risk stratification schema to be used in international clinical trials. For more information, see the International risk classification model section.
Other studies observed the following factors that affected prognosis:
Chemotherapy: Chemotherapy often decreases the size and extent of hepatoblastoma tumors, allowing complete resection.[51,54,66-68] Favorable response of the primary tumor to chemotherapy predicts its resectability, with favorable response defined as either a 30% decrease in tumor size by Response Evaluation Criteria In Solid Tumors (RECIST) or 90% or greater decrease in AFP levels. In turn, this favorable response predicted OS among all CHIC risk groups treated with neoadjuvant chemotherapy in the JPLT-2 Japanese national clinical trial.[69][Level of evidence B4]
Surgery: Cure of hepatoblastoma requires gross tumor resection. Hepatoblastoma is most often unifocal, so resection may be possible. Most patients survive if a hepatoblastoma is completely removed. However, because of vascular or other involvement, less than one-third of patients have lesions that are amenable to complete resection at diagnosis.[58] It is critically important that a child with probable hepatoblastoma be evaluated by a pediatric surgeon who is experienced in the techniques of extreme liver resection with vascular reconstruction. The child should also have access to a liver transplant program. In advanced tumors, surgical treatment of hepatoblastoma is a demanding procedure. Postoperative complications in high-risk patients decrease the OS rate.[70]
Orthotopic liver transplant: Orthotopic liver transplant is an additional treatment option for patients whose tumor remains unresectable after preoperative chemotherapy.[71,72] However, the presence of microscopic residual tumor at the surgical margin does not preclude a favorable outcome.[73,74] This outcome may result from additional courses of chemotherapy administered before or after resection.[66,67,73]
For more information about the outcomes associated with specific chemotherapy regimens, see Table 6.
Ninety percent of children with hepatoblastoma and two-thirds of children with hepatocellular carcinoma exhibit elevated levels of the serum tumor marker AFP, which parallels disease activity. The level of AFP at diagnosis and rate of decrease in AFP levels during treatment are compared with the age-adjusted reference range. Lack of a significant decrease in AFP levels with treatment may predict a poor response to therapy.[75] In an exploratory study of 34 children with hepatoblastoma, the rate of decrease in AFP and tumor volume, but not in RECIST I measurements, following two courses of treatment after diagnosis was predictive of EFS and OS.[76]
Absence of elevated AFP levels at diagnosis (AFP <100 ng/mL) occurs in a small percentage of children with hepatoblastoma and appears to be associated with very poor prognosis, as well as with the small cell undifferentiated variant of hepatoblastoma.[58] Some of these variants do not express SMARCB1 and may be considered rhabdoid tumors of the liver, which require alternative therapy. All small cell undifferentiated hepatoblastomas are tested for loss of SMARCB1 expression by immunohistochemistry to determine those that should be treated as a hepatoblastoma versus those that should be treated as rhabdoid tumors of the liver.[50,53,56,57,77,78]
Beta-hCG levels may also be elevated in children with hepatoblastoma or hepatocellular carcinoma, which may result in isosexual precocity in boys.[45,46]
For more information, see the Histology section in the Hepatoblastoma section.
Other variables have been proposed to be poor prognostic factors, but their significance has been difficult to define. In the SIOPEL-1 study, a multivariate analysis of prognosis after positive response to chemotherapy showed that only one variable, PRETEXT group, predicted OS, while metastasis and PRETEXT group predicted EFS.[77] In an analysis of the U.S. intergroup study from the time of diagnosis, well-differentiated fetal histology, small cell undifferentiated histology, and AFP less than 100 ng/mL were prognostic in a log rank analysis. PRETEXT group was prognostic among patients designated group III, but not group IV.[50,79] The CHIC study incorporated detailed hepatoblastoma patient data from multiple groups, establishing a solid foundation of risk factors.[79]
Hepatoblastoma arises from precursors of hepatocytes and can have several morphologies, including the following:[80]
Most often the tumor consists of a mixture of epithelial hepatocyte precursors. About 20% of tumors have stromal derivatives such as osteoid, chondroid, and rhabdoid elements. Occasionally, neuronal, melanocytic, squamous, and enteroendocrine elements are found. The following histological subtypes have clinical relevance:
An analysis of patients with initially resected hepatoblastoma tumors (before receiving chemotherapy) has suggested that patients with well-differentiated fetal (previously termed pure fetal) histology tumors have a better prognosis than patients with an admixture of more primitive and rapidly dividing embryonal components or other undifferentiated tissues. Studies have reported the following:
Thus, complete resection of a well-differentiated fetal hepatoblastoma may preclude the need for chemotherapy.
Small cell undifferentiated hepatoblastoma (SMARCB1 retained) is an uncommon hepatoblastoma variant. Histologically, small cell undifferentiated hepatoblastoma is typified by a diffuse population of small cells with scant cytoplasm resembling neuroblasts.[83] It is now recognized that small cell undifferentiated hepatoblastoma may be difficult to distinguish from malignant rhabdoid tumor of the liver, which has been conflated with small cell undifferentiated hepatoblastoma in past studies.
Small cell undifferentiated histology hepatoblastoma and rhabdoid tumors of the livers can be distinguished by the following characteristic abnormalities:
Historically, small cell undifferentiated hepatoblastoma was reported to occur at a younger age (6–10 months) than other cases of hepatoblastoma [50,84] and was associated with AFP levels that are in the reference range for age at presentation.[53,84] However, in a prospective study by the COG (AHEP0731 [NCT00980460]), the presence of small cell undifferentiated histology did not correlate with age, sex, or AFP levels at diagnosis.[86]
The Paediatric Hepatic International Tumour Trial (PHITT) designates any childhood liver tumor as rhabdoid tumor of the liver if it contains cells that lack SMARCB1 expression. Patients with SMARCB1-negative tumors, which are presumed to be related to rhabdoid tumors, may not be enrolled in the international trial, which addresses treatment of hepatoblastoma that includes small cell undifferentiated histology, hepatocellular carcinoma, and hepatic malignancy of childhood, not otherwise specified (NOS), but not rhabdoid tumor of the liver. In this trial, all patients with histology consistent with pure small cell undifferentiated hepatoblastoma, as assessed by the institutional pathologist, are required to have testing for SMARCB1 by immunohistochemistry according to the practices at the institution. In addition, presence of a blastemal component indicates conventional hepatoblastoma.[80]
A characteristic shared by both small cell undifferentiated hepatoblastoma and malignant rhabdoid tumor is the poor prognosis associated with each.[50,84,87] However, because small cell undifferentiated hepatoblastoma and rhabdoid tumor of the liver have not been discriminated in past studies, some of the prognostic features attributed to the former may have been contributed in part by the latter. Published studies of prognostic features related to small cell undifferentiated histology include the following:
The outcomes of the CHIC trial of childhood liver tumors may clarify some of the questions regarding these different histological and genetic findings.
There are significant differences among childhood cancer study groups in risk stratification used to determine treatment, making it difficult to compare results of the different treatments. Table 5 shows the variability in the definitions of risk groups.
COG (AHEP-0731) | SIOPEL (SIOPEL-3, -3HR, -4, -6) | GPOH | JPLT (JPLT-2 and -3) | |
---|---|---|---|---|
AFP = alpha-fetoprotein; COG = Children's Oncology Group; GPOH = Gesellschaft für Pädiatrische Onkologie und Hämatologie (Society for Paediatric Oncology and Haematology); JPLT = Japanese Study Group for Pediatric Liver Tumor; PRETEXT = PRE-Treatment EXTent of disease; SIOPEL = International Childhood Liver Tumors Strategy Group. | ||||
aAdapted from Czauderna et al.[79] | ||||
bFor more information about the annotations used in PRETEXT, see Table 2. | ||||
cThe COG and PRETEXT definitions of vascular involvement differ. | ||||
Very low risk | PRETEXT I or II; well-differentiated fetal histology; primary resection at diagnosis | |||
Low risk/standard risk | PRETEXT I or II of any histology with primary resection at diagnosis | PRETEXT I, II, or III | PRETEXT I, II, or III | PRETEXT I, II, or III |
Intermediate riskb | PRETEXT II, III, or IV unresectable at diagnosis; or V+c, P+, E+ | PRETEXT IV or any PRETEXT with rupture; or N1, P2, P2a, V3, V3a; or multifocal | ||
High riskb | Any PRETEXT with M+; AFP level <100 ng/mL | Any PRETEXT; V+, P+, E+, M+; AFP level <100 ng/mL; tumor rupture | Any PRETEXT with V+, E+, P+, M+ or multifocal | Any PRETEXT with M1 or N2; or AFP level <100 ng/mL |
The CHIC group developed a novel risk stratification system for use in international clinical trials on the basis of prognostic features present at diagnosis. CHIC unified the disparate definitions and staging systems used by pediatric cooperative multicenter trial groups, enabling the comparison of studies conducted by heterogeneous groups in different countries.[63] Original detailed clinical patient data were extracted from eight published clinical trials using central review of imaging and histology, and prognostic factors were identified by univariate analysis.[58]
Based on the initial univariate analysis of the data combined with historical clinical treatment patterns and data from previous large clinical trials, five backbone groups were selected, which allowed for further risk stratification. Subsequent multivariate analysis on the basis of these backbone groups defined the following clinical prognostic factors: PRETEXT group (I, II, III, or IV), presence of metastasis (yes or no), and AFP (≤100 ng/mL). The backbone groups are as follows:[63]
Other diagnostic factors (e.g., age) were queried for each of the backbone categories, including the presence of at least one of the following PRETEXT annotations (defined as VPEFR+, see Table 2) or AFP less than or equal to 100 ng/mL:[63]
An assessment of surgical resectability at diagnosis was added for PRETEXT I and II patients. Patients in each of the five backbone categories were stratified on the basis of backwards stepwise elimination multivariable analysis of additional patient characteristics, including age and presence or absence of PRETEXT annotation factors (V, P, E, F, and R). Each of these subcategories received one of four risk designations (very low, low, intermediate, or high). The result of the multivariate analysis was used to assign patients to very low-, low-, intermediate-, and high-risk categories, as shown in Figure 2. For example, the finding of an AFP level of 100 to 1,000 ng/mL was significant only among patients younger than 8 years in the backbone PRETEXT III group. The analysis enables prognostically similar risk groups to be assigned to the appropriate treatment groups on upcoming international protocols.[63]
Treatment options for newly diagnosed hepatoblastoma depend on the following:
Cisplatin-based chemotherapy has resulted in a survival rate of more than 90% for children with PRETEXT and POST-Treatment EXTent (POSTTEXT) group I and II resectable disease before or after chemotherapy.[54,56,67]
Chemotherapy regimens used in the treatment of hepatoblastoma and their respective outcomes are described in Table 6. For information describing each stage, see the Tumor Stratification by Imaging section.
Study | Chemotherapy Regimen | Number of Patients | Outcomes |
---|---|---|---|
AFP = alpha-fetoprotein; C5V = cisplatin, fluorouracil (5-FU), and vincristine; CARBO = carboplatin; CCG = Children’s Cancer Group; CDDP = cisplatin; CITA = pirarubicin-cisplatin; COG = Children's Oncology Group; DOXO = doxorubicin; EFS = event-free survival; GPOH = Gesellschaft für Pädiatrische Onkologie und Hämatologie (Society for Paediatric Oncology and Haematology); H+ = rupture or intraperitoneal hemorrhage; HR = high risk; IFOS = ifosfamide; IPA = ifosfamide, cisplatin, and doxorubicin; ITEC = ifosfamide, pirarubicin, etoposide, and carboplatin; JPLT = Japanese Study Group for Pediatric Liver Tumor; LR = low risk; NR = not reported; OS = overall survival; PLADO = cisplatin and doxorubicin; POG = Pediatric Oncology Group; PRETEXT = PRE-Treatment EXTent of disease; SIOPEL = International Childhood Liver Tumors Strategy Group; SR = standard risk; SUPERPLADO = cisplatin, doxorubicin, and carboplatin; THP = tetrahydropyranyl-adriamycin (pirarubicin); VP = vinorelbine and cisplatin; VPE+ = venous, portal, and extrahepatic involvement; VP16 = etoposide. | |||
aAdapted from Czauderna et al.,[79] Meyers et al.,[91] and Malogolowkin et al.[92] | |||
bStudy closed early because of inferior results in the CDDP/CARBO arm. | |||
INT0098 (CCG/POG) 1989–1992 | C5V vs. CDDP/DOXO | Stage I/II: 50 | 4-Year EFS/OS: |
I/II = 88%/100% vs. 96%/96% | |||
Stage III: 83 | III = 60%/68% vs. 68%/71% | ||
Stage IV: 40 | IV = 14%/33% vs. 37%/42% | ||
P9645 (COG)b 1999–2002 | C5V vs. CDDP/CARBO | Stage III: 38 | 3-year EFS/OS: |
III/IV: C5V = 60%/74%; CDDP/CARBO = 38%/54% | |||
Stage IV: 50 | |||
AHEP0731 (COG) 2010–2014 [93][Level of evidence C1] | LR: C5V (2 cycles) | LR (stage I/II): 49 | 5-year EFS: 88%; 5-year OS: 91% |
HB 94 (GPOH) 1994–1997 | I/II: IFOS/CDDP/DOXO | Stage I: 27 | 4-Year EFS/OS: |
I = 89%/96% | |||
Stage II: 3 | II = 100%/100% | ||
III/IV: IFOS/CDDP/DOXO + VP/CARBO | Stage III: 25 | III = 68%/76% | |
Stage IV: 14 | IV = 21%/36% | ||
HB 99 (GPOH) 1999–2004 | SR: IPA | SR: 58 | 3-Year EFS/OS: |
SR = 90%/88% | |||
HR: CARBO/VP16 | HR: 42 | HR = 52%/55% | |
SIOPEL-2 1994–1998 | SR: PLADO | PRETEXT I: 6 | 3-Year EFS/OS: |
SR: 73%/91% | |||
PRETEXT II: 36 | |||
PRETEXT III: 25 | |||
HR: CDDP/CARBO/DOXO | PRETEXT IV: 21 | HR: IV = 48%/61% | |
Metastases: 25 | HR: metastases = 36%/44% | ||
SIOPEL-3 1998–2006 | SR: CDDP vs. PLADO | SR: PRETEXT I: 18 | 3-Year EFS/OS: |
SR: CDDP = 83%/95%; PLADO = 85%/93% | |||
PRETEXT II: 133 | |||
PRETEXT III: 104 | |||
HR: SUPERPLADO | HR: PRETEXT IV: 74 | HR: Overall = 65%/69% | |
VPE+: 70 | |||
Metastases: 70 | Metastases = 57%/63% | ||
AFP <100 ng/mL: 12 | |||
SIOPEL-4 2005–2009 | HR: Block A: Weekly; CDDP/3 weekly DOXO; Block B: CARBO/DOXO | PRETEXT I: 2 | 3-Year EFS/OS: |
All HR = 76%/83% | |||
PRETEXT II: 17 | |||
PRETEXT III: 27 | |||
PRETEXT IV: 16 | HR: IV = 75%/88% | ||
Metastases: 39 | HR: Metastases = 77%/79% | ||
JPLT-1 1991–1999 | I/II: CDDP(30)/THP-DOXO | Stage I: 9 | 5-Year EFS/OS: |
I = NR/100% | |||
Stage II: 32 | II = NR/76% | ||
III/IV: CDDP(60)/THP-DOXO | Stage IIIa: 48 | IIIa = NR/50% | |
Stage IIIb: 25 | IIIb = NR/64% | ||
Stage IV: 20 | IV = NR/77% | ||
JPLT-2 1999–2010 [94][Level of evidence C1] | Initial surgery and 2 cycles of CITA | Stratum 1: PRETEXT I/II, 0 annotation factors except H+ (n = 40) | 5-Year EFS/OS: |
74.2%/89.9% | |||
2 cycles of CITA followed by surgery and 2–4 cycles of CITA | Stratum 2: PRETEXT II with multifocality (n = 80) | 84.8%/90.8% | |
2 cycles of CITA followed by 2 cycles of CITA (responders); attempted surgery including transplant | Stratum 3: PRETEXT I/II (annotation factors present) and III/IV (n = 176) responders | 71.6%/85.9% | |
2 cycles of CITA followed by 2 cycles of ITEC (nonresponders); attempted surgery including transplant | Stratum 4: PRETEXT I/II (annotation factors present) and III/IV (n = 59) nonresponders | 59.1%/67.3% |
Approximately 20% to 30% of children with hepatoblastoma have resectable disease at diagnosis. COG surgical guidelines (AHEP0731 [NCT00980460] appendix) recommend tumor resection at diagnosis without preoperative chemotherapy in children with PRETEXT I tumors and PRETEXT II tumors with greater than 1 cm radiographic margin on the vena cava and middle hepatic and portal veins. Outcomes for patients after undergoing a complete resection at diagnosis, compared with patients who had positive microscopic margins found at resection, are similar after receiving chemotherapy.[56,57,73]; [95][Level of evidence C1]
Prognosis varies depending on the histological subtype, as follows:
Treatment options for hepatoblastoma resectable at diagnosis showing non–well-differentiated fetal histology include the following:
Re-resection of positive microscopic margins may not be necessary. Conclusive evidence is lacking for tumors with resection at diagnosis compared with those with positive microscopic margins resected after preoperative chemotherapy.
Evidence (gross surgical resection, with or without microscopic margins, and postoperative chemotherapy):
Results of chemotherapy clinical trials are described in Table 6.
Treatment options for hepatoblastoma of well-differentiated fetal (pure fetal) histology resectable at diagnosis include the following:
Evidence (complete surgical resection followed by watchful waiting or chemotherapy):
Approximately 70% to 80% of children with hepatoblastoma have tumors that are not resected at diagnosis. COG surgical guidelines (AHEP0731 [NCT00980460] appendix) recommend a diagnostic biopsy without an attempt to resect the tumor in children with PRETEXT II tumors with less than 1-cm radiographic margin on the vena cava and middle hepatic vein and in all children with PRETEXT III and IV tumors.
Treatment options for hepatoblastoma that is not resectable or is not resected at diagnosis include the following:
Tumor rupture at presentation, resulting in major hemorrhage that can be controlled by transcatheter arterial embolization or partial resection to stabilize the patient, does not preclude a favorable outcome when followed by chemotherapy and definitive surgery.[107]
In recent years, most children with hepatoblastoma have been treated with chemotherapy. In European cancer centers, children with resectable hepatoblastoma at diagnosis are treated with preoperative chemotherapy, which may reduce the incidence of surgical complications at the time of resection.[54,56,73] Treatment with preoperative chemotherapy has been shown to benefit children with hepatoblastoma. In contrast, an American intergroup study of treatment of children with hepatoblastoma encouraged resection at the time of diagnosis for all tumors amenable to resection without undue risk. The study (COG-P9645) did not treat children with stage I tumors of well-differentiated fetal histology with preoperative or postoperative chemotherapy unless they developed progressive disease.[52] In this study, most patients with PRETEXT III and all PRETEXT IV tumors were treated with chemotherapy before resection or transplant.
Patients whose tumors remain unresectable after chemotherapy should consider a liver transplant.[54,71,98-102] In the presence of features predicting unresectability, early coordination with a pediatric liver transplant service is critical.[78] In the COG AHEP0731 (NCT00980460) study, early referral (i.e., based on imaging done after the second cycle of chemotherapy) to a liver specialty center with transplant capability was recommended for patients with POSTTEXT III tumors with positive V or P and POSTTEXT IV tumors with positive F.
Evidence (chemotherapy followed by reassessment of surgical resectability and complete surgical resection or liver transplant):
In the United States, patients with unresectable tumors have been treated with chemotherapy before resection or transplant.[51,52,66,67] On the basis of radiographic imaging, most stage III and IV hepatoblastomas are rendered resectable after two cycles of chemotherapy.[109] A combination of ifosfamide, cisplatin, and doxorubicin followed by postinduction resection has also been used in the treatment of advanced-stage disease.[110] Some centers have also used extended resection of selected POSTTEXT III and IV tumors rather than liver transplant.[78,111-114] Other options, such as TARE and TACE, have been used to shrink residual tumor mass. TARE may also facilitate surgical resection by tumor shrinkage when added to chemotherapy.[106]
The COG conducted a single-arm phase III trial (AHEP0731 [NCT00980460]) for patients with intermediate-risk hepatoblastoma. The study included 93 patients with unresectable nonmetastatic disease and 9 patients with a complete resection at diagnosis. All of the tumors had small cell undifferentiated histology. The addition of doxorubicin to standard treatment (cisplatin, fluorouracil, and vincristine) was assessed for feasibility and efficacy. In the 93 patients with initially unresectable disease, the 5-year EFS rate was 85% (95% CI, 79%–93%), and the OS rate was 95% (95% CI, 87%–98%).[115]
Chemotherapy followed by TACE, then high-intensity focused ultrasound, showed promising results in China for patients with PRETEXT III and IV tumors, some of which were resectable. Patients did not undergo surgical resection because of parent refusal.[116]
The outcomes of patients with metastatic hepatoblastoma at diagnosis are poor, but long-term survival and cure are possible.[51,66,67] Survival rates at 3 to 5 years range from 20% to 79%.[55,57,74,117] To date, the best outcomes for children with metastatic hepatoblastoma resulted from treatment with dose-dense cisplatin and doxorubicin, although significant toxicity was also noted (SIOPEL-4 [NCT00077389] trial).[74][Level of evidence B4]
Treatment options for hepatoblastoma with metastases at diagnosis include the following:
The standard combination chemotherapy regimen in North America is four courses of cisplatin/vincristine/fluorouracil [51] or doxorubicin/cisplatin,[52,54,55] followed by attempted complete tumor resection. If the tumor is completely removed, two postoperative courses of the same chemotherapy are usually given. Study results for different chemotherapy regimens have been reported. For more information, see Table 6.
High-dose chemotherapy with stem cell rescue does not appear to be more effective than standard multiagent chemotherapy.[118]
Evidence (chemotherapy followed by surgery to treat metastatic disease at diagnosis):
In patients with resected primary tumors, any remaining pulmonary metastases should be surgically removed, if possible.[55] Resection of pulmonary metastases may be facilitated by computed tomography needle localization or preoperative indocyanine green administration with intraoperative fluorescence localization.[119] A review of patients treated on a U.S. intergroup trial suggested that resection of metastasis may be done at the time of resection of the primary tumor.[117][Level of evidence C1]
If extrahepatic disease is in complete remission after chemotherapy, and the primary tumor remains unresectable, an orthotopic liver transplant may be performed.[52,57,74,110]
The outcome results are discrepant for patients with lung metastases at diagnosis who undergo orthotopic liver transplant after complete resolution of lung disease in response to pretransplant chemotherapy. Some studies have reported favorable outcomes for these patients,[57,74,102,110] while others have noted high rates of hepatoblastoma recurrence.[71,98,101,104] All of these studies are limited by small patient numbers. Additional studies are needed to better define outcomes for this subset of patients. Recent clinical trials have resulted in few pulmonary recurrences in children who presented with metastatic disease and underwent liver transplants.[57,59,74]
If extrahepatic disease is not resectable after chemotherapy or the patient is not a transplant candidate, alternative treatment approaches include the following:
The prognosis for a patient with progressive or recurrent hepatoblastoma depends on several factors, including the following:[126]
Treatment options for progressive or recurrent hepatoblastoma include the following:
If possible, isolated metastases are resected completely in patients whose primary tumor is controlled.[128] A retrospective analysis of patients in the SIOPEL 1, 2, and 3 studies showed a 12% incidence of recurrence after complete remission by imaging and AFP levels. Outcome after recurrence was best if the tumor was amenable to surgery. Of patients who underwent chemotherapy and surgery, the 3-year EFS rate was 34%, and the OS rate was 43%.[126][Level of evidence C1]
If all of the recurrent disease cannot be surgically removed, patients should consider enrolling in a clinical trial. Phase I and phase II clinical trials may be appropriate.
Combined vincristine/irinotecan and single-agent irinotecan have been used with some success.[123]; [122][Level of evidence C1]
A review of COG phase I and II studies found no promising agents for relapsed hepatoblastoma.[130]
Information about National Cancer Institute (NCI)–supported clinical trials can be found on the NCI website. For information about clinical trials sponsored by other organizations, see the ClinicalTrials.gov website.
The annual incidence of hepatocellular carcinoma in the United States is 0.4 cases per 1 million children between the ages of 0 and 14 years and 1.5 cases per 1 million adolescents aged 15 to 19 years.[1] The incidence of hepatocellular carcinoma in adults in the United States has steadily increased since the 1970s, possibly because of the increased frequency of chronic hepatitis C infection.[2] However, the incidence of hepatocellular carcinoma in children has not increased. In several Asian countries, the incidence of hepatocellular carcinoma in children is 10 times higher than in North America. The high incidence appears to be related to the incidence of perinatally acquired hepatitis B virus (HBV), which can be prevented in most cases by vaccination and administration of hepatitis B immune globulin to the newborn child.[3]
Fibrolamellar carcinoma of the liver was thought to be a subtype of hepatocellular carcinoma. However, it is now recognized as a distinct cancer. For more information, see the Fibrolamellar Carcinoma section.
Conditions associated with hepatocellular carcinoma are described in Table 7.
Associated Disorder | Clinical Findings |
---|---|
Alagille syndrome [4] | Broad prominent forehead, deep-set eyes, and small prominent chin. Abnormality of bile ducts leads to intrahepatic scarring. For more information, see the Alagille syndrome section. |
Glycogen storage diseases I–IV [5] | Symptoms vary by individual disorder. |
Hepatitis B and C [6-8] | For more information, see the Hepatitis B and hepatitis C infection section. |
Progressive familial intrahepatic cholestasis [9,10] | Symptoms of jaundice, pruritus, and failure to thrive begin in infancy and progress to portal hypertension and liver failure. |
Tyrosinemia [11] | First few months of life: failure to thrive, vomiting, jaundice. |
Alagille syndrome is an autosomal dominant genetic syndrome that is usually caused by a variant in or deletion of the JAG1 gene. It involves the bile ducts of the liver, the heart, and blood vessels in the brain and kidney. Patients develop a characteristic facies.[4]
In children, hepatocellular carcinoma is associated with perinatally acquired HBV. In adults, it is associated with chronic HBV and hepatitis C virus (HCV) infection.[6-8] Widespread hepatitis B immunization has decreased the incidence of hepatocellular carcinoma in Asia.[3] Compared with adults, the incubation period from hepatitis virus infection to the genesis of hepatocellular carcinoma is extremely short in a small subset of children with perinatally acquired virus. Variants in the MET gene could be one mechanism that results in a shortened incubation period.[12]
HCV infection is associated with development of cirrhosis and hepatocellular carcinoma that takes decades to develop and is generally not seen in children.[8] Unlike in adults, cirrhosis in children is much less commonly involved in the development of hepatocellular carcinoma and is found in only 20% to 35% of children with hepatocellular carcinoma tumors.
Specific types of nonviral liver injury and cirrhosis that are associated with hepatocellular carcinoma in children include the following:
In an Iranian study, 36 children underwent liver transplant for tyrosinemia.[15] Twenty-two children had liver nodules greater than 10 cm, and in 20 children, the nodules were cirrhotic. Median age at transplant was 3.9 years. Five of 19 children older than 2 years had hepatocellular carcinoma, and no children younger than 2 years had hepatocellular carcinoma in the resected liver.
Genomic findings related to hepatocellular carcinoma include the following:
TERT variants were observed in two of four transitional liver cell tumor cases tested.[18] TERT variants are also commonly observed in adults with hepatocellular carcinoma.[19]
To date, these genetic variants have not been used to select therapeutic agents for investigation in clinical trials.
For more information, see the Diagnosis section in the Hepatoblastoma section.
In the United states, the 5-year relative survival rate is 55% for children and adolescents with hepatocellular carcinoma.[1] The 5-year survival for patients with hepatocellular carcinoma may depend on the stage of the disease. In an intergroup chemotherapy study conducted in the 1990s, seven of eight stage I patients survived, and less than 10% of stage III and IV patients survived.[20,21] An analysis of Surveillance, Epidemiology, and End Results (SEER) Program data found a 5-year overall survival (OS) rate of 24%, a 10-year rate of 23%, and a 20-year rate of 8% in patients aged 19 years and younger, suggesting improved outcome related to more recent treatment. In a multivariate analysis of the SEER data, surgical resection, localized tumor, and non-Hispanic ethnicity were all associated with improved outcome. Patients who had a complete surgical resection had an OS rate of 60%, compared with an OS rate of 0% for patients who had an incomplete resection.[22][Level of evidence C1]
The 5-year OS rates by PRE-Treatment EXTent of disease (PRETEXT) group for patients with hepatocellular carcinoma in the SIOPEL-1 trial were found to be the following:[23]
For more information about PRETEXT grouping, see the PRETEXT and POSTTEXT Group Definitions section.
Hepatocellular carcinoma prognosis by Evans surgical stage. Several staging systems exist for hepatocellular carcinoma, including the American Joint Committee on Cancer (AJCC) tumor-node-metastasis staging system (TNM) and the Barcelona Clinic Liver Cancer Staging System. However, the international prospective collaborative Paediatric Hepatic International Tumour Trial (PHITT) used the Evans Surgical Staging for childhood liver cancer. For more information, see the Evans Surgical Staging for Childhood Liver Cancer section.
Factors affecting prognosis include the following:
The cells of hepatocellular carcinoma are epithelial in appearance. Hepatocellular carcinoma commonly arises in the right lobe of the liver.
Hepatocellular neoplasm, NOS, is also known as transitional liver cell tumor. This tumor, with characteristics of both hepatoblastoma and hepatocellular carcinoma, is a rare neoplasm found in older children and adolescents. It has a putative intermediate position between hepatoblasts and more mature hepatocyte-like tumor cells. The tumor cells may vary in regions of the tumor between classical hepatoblastoma and obvious hepatocellular carcinoma. In the international consensus classification, these tumors are referred to as hepatocellular neoplasm, NOS.[27] The tumors are usually unifocal and may have central necrosis at presentation. Response to chemotherapy has not been rigorously studied, but it is thought to be similar to that of hepatocellular carcinoma.[28]
Treatment options for newly diagnosed hepatocellular carcinoma depend on the following:
Treatment options for hepatocellular carcinoma that is resectable at diagnosis include the following:
Surgical resection and chemotherapy are the mainstays of treatment for resectable hepatocellular carcinoma.
Evidence (complete surgical resection followed by chemotherapy):
Cisplatin and doxorubicin may be administered as adjuvant therapy because these agents may have activity in the treatment of hepatocellular carcinoma.[23]
Evidence (complete surgical resection without chemotherapy):
Despite improvements in surgical techniques, chemotherapy delivery, and patient supportive care in the past 20 years, clinical trials of chemotherapy have not shown improved survival rates for pediatric patients with hepatocellular carcinoma.[23] The International Childhood Liver Tumors Strategy Group (SIOPEL) studies in Europe have observed no improvement in 5-year OS since 1990. The only long-term survivors were patients whose tumors were resectable at diagnosis, which was less than 30% of children entered in the study.[31] However, some liver transplant studies (complete resection with transplant with or without neoadjuvant chemotherapy) have shown OS rates that are superior to the SIOPEL studies.[26,32-35]
Treatment options for nonmetastatic hepatocellular carcinoma that is not resectable at diagnosis include the following:
The use of neoadjuvant chemotherapy or TACE to enhance resectability or liver transplant, which may result in complete resection of tumor, is necessary for a cure.
Evidence (chemotherapy followed by surgery):
Evidence (chemotherapy, TARE, or TACE followed by reassessment of surgical resectability; treatment options, including liver transplant, for unresectable primary tumor after chemotherapy, TARE, or TACE):
If the primary tumor is not resectable after chemotherapy and the patient is not a transplant candidate, alternative treatment approaches used in adults include the following:
There are limited data on the use of these alternative treatment approaches in children.
Limited data from a European pilot study suggest that sorafenib was well tolerated in 12 children and adolescents with newly diagnosed advanced hepatocellular carcinoma when given in combination with standard chemotherapy of cisplatin and doxorubicin.[44] Additional study is needed to define its role in the treatment of children with hepatocellular carcinoma.
Cryosurgery, intratumoral injection of alcohol, and radiofrequency ablation can successfully treat small (<5 cm) tumors in adults with cirrhotic livers.[40,45,46] Some local approaches such as cryosurgery, radiofrequency ablation, and TACE, which suppress hepatocellular carcinoma tumor progression, are used as bridging therapy in adults to delay tumor growth while on a waiting list for cadaveric liver transplant.[47] In a pediatric study of eight patients with hepatocellular carcinoma, two patients died of progressive disease without transplant. Treatment with TACE stabilized disease in six patients, for a mean of 141 days to reach transplant.[48][Level of evidence C1] Five patients were alive at the end of the observation period, and one patient died of disease. For more information, see Primary Liver Cancer Treatment.
Most of the information about the use of targeted therapy or immunotherapy for patients with nonresectable hepatocellular carcinoma or metastatic disease has been informed by trials in adults. To learn more about these treatments in adults, see the Treatment of Locally Advanced or Metastatic Primary Liver Cancer section in Primary Liver Cancer Treatment.
No specific treatment has proven effective for metastatic hepatocellular carcinoma in children and adolescents.
In two prospective trials, cisplatin plus either vincristine/fluorouracil or continuous-infusion doxorubicin was ineffective in adequately treating 25 patients with metastatic hepatocellular carcinoma.[21,23] Occasional patients may transiently benefit from treatment with cisplatin/doxorubicin therapy, especially if the localized hepatic tumor shrinks adequately enough to allow resection of disease and the metastatic disease disappears or becomes resectable.
Although HBV-related hepatocellular carcinoma is not common in children in the United States, nucleotide/nucleoside analog HBV inhibitor treatment improves postoperative prognosis in children and adults treated in China.[49]
Treatment options for HBV-related hepatocellular carcinoma include the following:
Evidence (antiviral therapy):
The prognosis for a patient with recurrent or progressive hepatocellular carcinoma is extremely poor.[50]
Treatment options for progressive or recurrent hepatocellular carcinoma include the following:
In a retrospective single-institution study, ten children aged 6 to 17 years with recurrent hepatocellular carcinoma were treated with radiofrequency ablation. After one ablation, 14 of 15 target lesions had complete responses. None of these lesions progressed. The 1-year OS rate was 77.8%, and the 3-year OS rate was 44.4%.[52][Level of evidence C1]
Treatment with sorafenib has resulted in improved progression-free survival in adults with advanced hepatocellular carcinoma. For adult patients who received sorafenib, the median survival and time to radiological progression were about 3 months longer than for patients who received a placebo.[53]
Information about National Cancer Institute (NCI)–supported clinical trials can be found on the NCI website. For information about clinical trials sponsored by other organizations, see the ClinicalTrials.gov website.
Fibrolamellar carcinoma was previously considered a rare subtype of hepatocellular carcinoma. It is also called fibrolamellar hepatocellular carcinoma and fibrolamellar liver cancer. With the 2014 discovery of a pathognomonic DNAJB::PRKACA chimera that defines this entity, it has been redefined as a distinct type of cancer, separate from hepatocellular carcinoma.[1]
Fibrolamellar carcinoma most commonly arises in adolescents and adults, although it can also arise in young children and older adults.[2,3] The Surveillance, Epidemiology, and End Results (SEER) Program reports an annual fibrolamellar carcinoma incidence of 0.2 cases per 1 million based on pathology reporting. However, clinical practice estimates are much higher, and tiered computational analysis of clinical data places this estimate five to eight times higher.[4] Unlike hepatoblastoma in children and hepatocellular carcinoma in adults, fibrolamellar carcinoma in adolescents and young adults is not clearly increasing in incidence over time.[3,5] Fibrolamellar carcinoma, unlike hepatocellular carcinoma, is not strongly associated with a history of cirrhosis, hepatitis B virus (HBV), or hepatitis C virus (HCV) infection.[2]
Carney complex is caused by heterozygous germline pathogenic variants in PRKAR1A and is an autosomal dominant genetic syndrome.[6] It is characterized by skin pigmentary abnormalities. It is also associated with cardiac, endocrine, cutaneous, and neural myxomatous tumors. Fibrolamellar carcinoma is observed, albeit rarely, in patients with Carney complex.[7] Fibrolamellar carcinoma arising in patients with Carney complex is negative for PRKACA rearrangements and instead shows loss of PRKAR1A protein expression.[7]
Fibrolamellar carcinoma was first described as a distinct pathological entity by Edmonson in 1956. It is characterized by large cells with eosinophilic cytoplasm, central nuclei with vesiculated chromatin and prominent macronucleoli, along with dense bands of lamellar fibrosis that gives the tumor its name.[8]
Fibrolamellar carcinoma is a rare subtype of hepatocellular carcinoma observed in older children and young adults. It is characterized by an approximately 400 kB deletion on chromosome 19, which produces a chimeric transcript. This chimeric RNA codes for a protein containing the amino-terminal domain of DNAJB1, a homolog of the molecular chaperone DNAJ, fused in frame with PRKACA, the catalytic domain of protein kinase A.[1]
Fibrolamellar carcinoma is not associated with cirrhosis of the liver. It was previously thought to confer a more favorable prognosis than hepatocellular carcinoma.[3,5,9] The improved outcomes of patients with fibrolamellar carcinoma in older studies may be related to a higher proportion of tumors being less invasive and more resectable in the absence of cirrhosis. However, the outcomes of patients with fibrolamellar carcinoma in recent prospective studies, when compared stage-to-stage and PRETEXT group–to–PRETEXT group, are the same as the outcomes of patients with conventional hepatocellular carcinomas.[10,11]; [12][Level of evidence C1]
Surgery is the standard of care for patients with radiographically localized fibrolamellar carcinoma. For patients with distant spread of disease, systemic therapy is based on the current treatments for pediatric or adult hepatocellular carcinoma, albeit with similarly poor effectiveness. For more information about the treatments used for fibrolamellar carcinoma, see the Treatment of Hepatocellular Carcinoma section.
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Undifferentiated embryonal sarcoma of the liver (UESL) is a distinct clinical and pathological entity and accounts for 2% to 15% of pediatric hepatic malignancies.[1]
UESL presents as an abdominal mass, often with pain or malaise, usually between the ages of 5 and 10 years. Widespread infiltration throughout the liver and pulmonary metastasis are common. It may appear solid or cystic on imaging, frequently with central necrosis. Undifferentiated sarcomas, like small cell undifferentiated hepatoblastomas, should be examined for loss of SMARCB1 expression by immunohistochemistry to help rule out rhabdoid tumor of the liver.
It is important to make the diagnostic distinction between UESL and biliary tract rhabdomyosarcoma because they share some common clinical and pathological features, but treatment differs between the two, as shown in Table 8.[1] For more information, see Childhood Rhabdomyosarcoma Treatment.
Undifferentiated Embryonal Sarcoma of the Liver | Biliary Tract Rhabdomyosarcoma | |
---|---|---|
aAdapted from Nicol et al.[1] | ||
Median Age at Diagnosis | 10.5 y | 3.4 y |
Tumor Location | Often arises in the right lobe of the liver | Often arises in the hilum of the liver |
Biliary Obstruction | Unusual | Frequent; jaundice is a common presenting symptom |
Treatment | Surgery and chemotherapy | Surgery (usually biopsy only), radiation therapy, and chemotherapy |
Distinctive histological features of UESL include intracellular hyaline globules and marked anaplasia on a mesenchymal background.[2] Many UESL tumors contain diverse elements of mesenchymal cell maturation, such as smooth muscle and fat.
Strong clinical and histological evidence suggests that UESL can arise within preexisting mesenchymal hamartomas of the liver, which are large, benign, multicystic masses that present in the first 2 years of life.[1] In a report of 11 cases of UESL, 5 arose in association with mesenchymal hamartomas of the liver, and transition zones between the histologies were noted.[3] Many mesenchymal hamartomas of the liver have a characteristic translocation with a breakpoint at 19q13.4, and several UESLs have the same translocation.[4,5] Some UESLs arising from mesenchymal hamartomas of the liver may have complex karyotypes not involving 19q13.4.[4]
The overall survival (OS) rates of children with UESL appear to be substantially higher than 50% when combining reports, although all series are small and may have selection bias.[6]; [7-17][Level of evidence C1]
The Childhood Cancer Database, which does not provide central review of pathology or reliable details of nonsurgical treatment, reported on 103 children with UESL diagnosed between 1998 and 2012. The 5-year OS rate was 86% for all patients and 92% for those treated with combination surgery and chemotherapy. A multivariate analysis of the nonsurgical data revealed statistically significant poorer outcomes for patients with tumors larger than 15 cm. Seven of ten children who presented with metastases and ten of ten children who underwent orthotopic liver transplant survived at least 5 years, but details of their treatment were not presented.[18]
A retrospective study combined data from three European studies to identify 64 patients with UESL.[19][Level of evidence C1] The tumors were staged according to Intergroup Rhabdomyosarcoma Study (IRS) clinical grouping. Fourteen patients had IRS group I disease, 9 had IRS group II disease, 38 had IRS group III disease, and 4 had IRS group IV disease. A variety of chemotherapy regimens were used, with either neoadjuvant or adjuvant chemotherapy. Most regimens included alkylators and anthracyclines. Some patients also received radiation therapy. The 5-year event-free survival (EFS) rate was 89.1% (95% confidence interval [CI], 78.4%–94.6%), and the OS rate was 90.1% (95% CI, 79.3%–95.3%).
UESL is rare. Only small series have been published regarding treatment.[20]
Treatment options for UESL include the following:
The generally accepted approach is resection of the primary tumor mass in the liver when possible.[18] Use of aggressive chemotherapy regimens seems to have improved the OS of patients with UESL. Neoadjuvant chemotherapy can be effective in decreasing the size of an unresectable primary tumor mass, resulting in resectability.[8-11] Most patients are treated with chemotherapy regimens used for pediatric rhabdomyosarcoma or Ewing sarcoma without cisplatin.[6]; [7-16,21][Level of evidence C1]
Evidence (surgical resection and chemotherapy):
Liver transplant has occasionally been used to successfully treat an otherwise unresectable primary tumor.[14,16,18,23]
Information about National Cancer Institute (NCI)–supported clinical trials can be found on the NCI website. For information about clinical trials sponsored by other organizations, see the ClinicalTrials.gov website.
Choriocarcinoma of the liver is a very rare tumor that appears to originate in the placenta during gestation. It presents with a liver mass in the first few months of life. Metastasis from the placenta to maternal tissues occurs in many cases, necessitating beta-human chorionic gonadotropin (beta-hCG) testing of the mother. Infants are often unstable at diagnosis because of hemorrhage of the tumor.
Clinical diagnosis may be made without biopsy on the basis of tumor imaging of the liver associated with extremely high serum beta-hCG levels and alpha-fetoprotein (AFP) levels in the reference range for age.[1]
Cytotrophoblasts and syncytiotrophoblasts are both present. The former are closely packed nests of medium-sized cells with clear cytoplasm, distinct cell margins, and vesicular nuclei. The latter are very large, multinucleated syncytia formed from the cytotrophoblasts.[2]
The prognosis of patients with infantile choriocarcinoma of the liver is often poor because of the instability at presentation from hemorrhage. A 2017 case report and literature review found 32 cases, with 6 long-term survivors. The authors emphasized the opportunity for early diagnosis and treatment of this very chemosensitive tumor.[3]
Treatment options for infantile choriocarcinoma of the liver include the following:
Initial surgical removal of the tumor mass may be difficult because of its friability and hemorrhagic tendency. Surgical removal of the primary tumor is often performed after neoadjuvant chemotherapy.[1]
Maternal gestational trophoblastic tumors are exquisitely sensitive to methotrexate. Many women, including those with distant metastases, are cured with single-agent chemotherapy. Maternal and infantile choriocarcinoma both come from the same placental malignancy. The combination of cisplatin, etoposide, and bleomycin, as used in other pediatric germ cell tumors, has been effective in some patients and is followed by resection of the residual mass. Use of neoadjuvant methotrexate in infantile choriocarcinoma, although often resulting in a response, has not been uniformly successful.[1]
A case report of neoadjuvant chemotherapy followed by successful liver transplant highlights the opportunity for this therapy in children whose tumors remain unresectable after chemotherapy.[4]
Information about National Cancer Institute (NCI)–supported clinical trials can be found on the NCI website. For information about clinical trials sponsored by other organizations, see the ClinicalTrials.gov website.
Careful attention to clinical history, physical examination, laboratory evaluation, and radiological imaging is essential for an appropriate diagnosis of vascular liver tumors. If there is any doubt about the accuracy of the diagnosis, a biopsy should be performed.
The different diagnoses of vascular tumors of the liver include the following:
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The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.
Added text to state that fibrolamellar carcinoma most commonly arises in adolescents and adults, although it can also arise in young children and older adults.
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This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the treatment of childhood liver cancer. It is intended as a resource to inform and assist clinicians in the care of their patients. It does not provide formal guidelines or recommendations for making health care decisions.
This summary is reviewed regularly and updated as necessary by the PDQ Pediatric Treatment Editorial Board, which is editorially independent of the National Cancer Institute (NCI). The summary reflects an independent review of the literature and does not represent a policy statement of NCI or the National Institutes of Health (NIH).
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PDQ® Pediatric Treatment Editorial Board. PDQ Childhood Liver Cancer Treatment. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/types/liver/hp/child-liver-treatment-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389232]
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