Intraocular Retinoblastoma Treatment

Unilateral Disease
        Standard treatment options
Bilateral Disease
        Standard treatment options
Treatment Options Under Clinical Evaluation
        Current Clinical Trials

Treatment of retinoblastoma is individualized and considers the age of the patient, laterality, potential for vision, and intraocular tumor burden. Treatment options consider both cure of the disease and preservation of sight.[1-3] Different combinations of the following approaches may be applied to the individual patient, considering the two main scenarios, unilateral and bilateral disease.

Treatment options for the involved eye include the following:

1. Enucleation: If the tumor is massive and there is little expectation for useful vision in the affected eye, up-front enucleation may be indicated, depending on laterality. Patients must be monitored closely for orbital recurrence of disease, particularly in the first 2 years after enucleation.[4][Level of evidence: 3iiA] Recurrence in the orbit is often associated with systemic disease (85%) and should be treated with aggressive therapy.

2. Radiation therapy:
   • External-beam radiation therapy (EBRT): Retinoblastoma is a very radiosensitive malignancy; EBRT doses ranging from 35 Gy to 46 Gy usually result in long-term remissions. Because of the need to sedate young children and the intricacies of field planning, special expertise in pediatric radiation therapy is important. Newer methods of delivering EBRT are being used at many centers in an attempt to reduce adverse long-term effects. This includes intensity-modulated radiation therapy, stereotactic radiation therapy, and proton-beam radiation therapy (charged-particle radiation therapy).[5-7] EBRT in infants causes growth failure of the orbital bones and results in cosmetic deformity. It also increases the risk of subsequent neoplasms in children with hereditary retinoblastoma.

   • Brachytherapy: Brachytherapy with radioactive plaques is very effective in the treatment of localized retinal tumors that are not amenable to other means of local therapy.[8-10]

3. Local treatments: For patients undergoing eye salvage treatment, aggressive local therapy is required.
   • Cryotherapy: Cryotherapy is based on the application of a cryoprobe to the sclera in the immediate vicinity of the retinal tumor. It is used as primary therapy or with chemotherapy for tumors smaller than 4 disc diameters (DD) in the anterior portion of the retina.

   • Laser therapy (thermotherapy): Laser therapy may be used as primary therapy for small tumors or in combination with chemotherapy for larger tumors. Traditional photocoagulation, in which the laser was applied around the tumor, has given way to thermotherapy. Thermotherapy is delivered directly to the tumor surface via infrared wavelengths of light.[11]

4. Systemic chemotherapy: Systemic chemotherapy plays a role both in the adjuvant setting for patients with high-risk pathology, and in the eye-salvage regimens, where it is used in conjunction with aggressive focal treatments. During the past 15 years, systemic chemotherapy to reduce tumor volume (chemoreduction) and to avoid the long-term effects of radiation therapy for patients with intraocular tumors has succeeded in rendering many eyes amenable to treatment with cryotherapy or laser therapy.[1,12,13]; [14][Level of evidence: 3iiDiii] Chemotherapy may also be continued or initiated with concurrent local control interventions.[15] Factors such as tumor location (macula), patient age (patient older than 2 months), and tumor size correlate with responsiveness to chemotherapy.[15,16]

   Multiagent chemotherapy is generally used, although carboplatin as a single agent causes shrinkage of retinoblastoma tumors.[17]; [18][Level of evidence: 3iiiDiii] Most standard regimens incorporate vincristine, carboplatin, and etoposide, although a two-drug regimen without etoposide may also be effective for early intraocular stages.[1,12,13,16,19-22] The success rate of these trials varies from center to center, but overall, the rate is highest for discrete tumors without vitreous seeding. Local tumor recurrence is not uncommon in the first few years after treatment [23] and can often be successfully treated with focal therapy.[10] Among patients with hereditary disease, younger patients and those with positive family histories are more likely to form new tumors. Chemotherapy may treat small, previously undetected lesions by slowing their growth, and this may improve overall salvage with focal therapy.[24]

   There are data suggesting that the use of systemic chemotherapy may decrease the risk of development of trilateral retinoblastoma.[25]

5. Subtenon (subconjunctival) chemotherapy: Periocular delivery of carboplatin results in high intraocular concentrations of the agent, and this approach is often used in ocular salvage approaches, particularly when there is a high intravitreous tumor burden. Carboplatin is administered by the treating ophthalmologist into the subtenon space, and it is generally used in conjunction with systemic chemotherapy and local ophthalmic therapies.[26-28] Responses have also been noted with subtenon topotecan.[29]

6. Ophthalmic artery infusion of chemotherapy: Direct delivery of chemotherapy into the eye globe via cannulation of the ophthalmic artery is a feasible and effective method for ocular salvage. Melphalan was the chemotherapeutic agent used in the first studies, although it can be associated with significant local side effects, including third cranial nerve palsy, orbital edema, permanent retinal detachment, vitreous hemorrhage, and retinal pigment epithelium changes.[30] Other agents such as topotecan and carboplatin are also being tested. Ocular salvage rates are greater than 70% when ophthalmic artery infusion of chemotherapy is used as primary treatment, although success rates are inferior when this approach is used after failure of systemic chemotherapy or radiation.[31-33] Retinal and choroidal vasculopathy may occur in 10% to 20% of patients.[34] This modality continues to undergo study at very specialized retinoblastoma treatment centers, but preliminary data appear to indicate that this treatment modality results in satisfactory ocular salvage rates in patients with intraocular unilateral retinoblastoma.[31,33-38]

   This treatment is not without complications in some cases.[31,37,39]

Because unilateral disease is usually massive and there is often no expectation that useful vision can be preserved, up-front surgery (enucleation) is usually recommended. Careful examination of the enucleated specimen by an experienced pathologist is necessary to determine whether high-risk features for metastatic disease are present. These features include anterior chamber seeding, choroidal involvement, tumor beyond the lamina cribrosa, or scleral and extrascleral extension.[40-42] Systemic adjuvant therapy with vincristine, doxorubicin, and cyclophosphamide or with vincristine, carboplatin, and etoposide has been used in patients with certain high-risk features assessed by pathologic review after enucleation to prevent the development of metastatic disease,[43-46]; [47][Level of evidence: 2A] with the suggestion of success compared with historical controls.[48][Level of evidence: 3iiDiii]

Patients with unilateral disease may also be offered chemotherapy and aggressive focal treatments in an attempt to save the eye and preserve vision.[1,49,50] Ocular salvage rates correlate with intraocular stage.[51] In selected children with unilateral disease, R-E Group correlated with successful chemoreduction: 11% of children classified as having R-E Group II or III disease; 60% of children having R-E Group IV disease; and 100% of children having R-E Group V disease required enucleation or EBRT within 5 years of treatment.[52] Caution must be exerted with extended chemotherapy and delayed enucleation when tumor control does not appear to be possible. Pre-enucleation chemotherapy for eyes with advanced intraocular disease may result in downstaging and underestimate the pathological evidence of extraretinal and extraocular disease, thus, increasing the risk of dissemination.[53]

Pilot studies have evaluated the delivery of chemotherapy via ophthalmic artery cannulation as initial treatment for advanced unilateral and bilateral intraocular retinoblastoma. In the setting of a multidisciplinary, state-of-the-art center, intra-arterial chemotherapy may result in ocular salvage rates in excess of 80% for patients with advanced intraocular unilateral retinoblastoma.[31,35][Level of evidence: 3iiiDii]; [32][Level of evidence: 3iiiDiv]

Because a proportion of children who present with unilateral retinoblastoma will eventually develop disease in the opposite eye, it is very important that children with unilateral retinoblastoma receive periodic examinations of the unaffected eye, regardless of the treatment they received. Asynchronous bilateral disease occurs most frequently in patients with affected parents and in children diagnosed during the first months of life. Pre-enucleation magnetic resonance imaging has low sensitivity and specificity for the detection of high-risk pathology.[54] As discussed, genetic counseling and testing at the time of diagnosis is the key to defining risk and planning follow-up.

The management of bilateral disease depends on the extent of the disease in each eye. Systemic therapy should be chosen based on the eye with more extensive disease. Treatment modality options described for unilateral disease may be applied to one or both affected eyes in patients with bilateral disease.

Usually the disease is more advanced in one eye, with less involvement in the other eye. Overall treatment management is dictated by the most advanced eye. While up-front enucleation of an advanced eye and risk-adapted adjuvant chemotherapy may be required, a more conservative approach using primary chemoreduction with close follow-up for response and focal treatment (e.g., cryotherapy or laser therapy) may be indicated. EBRT is now reserved for patients whose eyes do not respond adequately to primary systemic chemotherapy and focal consolidation.

A number of large centers in Europe and North America have published trial results using systemic chemotherapy in conjunction with aggressive focal consolidation for patients with bilateral disease.[1,20,23,24,50,51,55-63]; [22][Level of evidence: 3iiDiv] Chemotherapy may shrink the tumors (chemoreduction), allowing greater efficacy of subsequent focal therapy.[1,40] Treatment strategies often differ in terms of chemotherapy regimens and local control measures.

Centers using the R-E classification have demonstrated that the goal to save eyes may be achievable for tumors that are R-E Group IV or lower. The backbone of the chemoreduction protocols has generally been carboplatin, etoposide, and vincristine (CEV). Studies from The Children's Hospital of Philadelphia and Wills Eye Hospital reported that enucleation or EBRT may be avoided in R-E Group I, II, and III eyes when patients were treated with six cycles.[1,12,21] Tumors associated with massive vitreous or subretinal seeds have proven problematic.[64] Local control was often transient in patients with vitreous seeding or very large tumors (R-E Group V), and fewer than half of patients were treated successfully without requiring EBRT and/or enucleation.[1,12]

Other researchers reported the use of nine courses of CEV with the addition of high-dose cyclosporine A (a modulator of the p-glycoprotein) for eight R-E Group V eyes with an 88% (7 out of 8 eyes) success rate without the use of EBRT or enucleation.[58,59] However, conflicting results were seen in another study using the cyclosporine regimen in ten R-E Group V eyes, which reported only a 20% (2 out of 10 eyes) success rate.[60]

The International Classification system for staging intraocular retinoblastoma is a better predictor of treatment success for the use of systemic chemotherapy in combination with local control. (Refer to the Treatment Options Under Clinical Evaluation section of this summary for a more complete description of the International Classification system.) The combinations of carboplatin and etoposide (CE) [22,65] or CEV [66,67] in conjunction with local control have resulted in ocular salvage rates above 90% for early intraocular disease (Groups A and B eyes), 70% to 90% for Group C eyes, and 40% to 50% for Group D eyes.[22,65,67]; [65][Level of evidence: 3iiDiv] However, for patients with advanced intraocular disease (typically Group D eyes), EBRT is frequently required for ocular salvage.[65]; [66][Level of evidence: 3iiDiii]

For patients with large intraocular tumor burden or with subretinal or vitreous seeds (Groups C and D eyes), the use of periocular chemotherapy, usually in combination with systemic therapy, has been explored.[26,68] However, the outcome of this approach on ocular salvage is not well defined.

The treatment recommendation for Group E eyes is up-front enucleation. The use of prolonged systemic chemotherapy for Group E eyes to avoid or delay enucleation has been associated with lower disease-specific survival (P < .001).[53][Level of evidence: 3iiiB]

Delivery of chemotherapy via ophthalmic artery cannulation has also been shown to be feasible and effective in patients with bilateral disease, in both the up-front and salvage settings.[31,35][Level of evidence: 3iiDii] However, this treatment should only be performed in an experienced center with a state-of-the-art treatment infrastructure and a dedicated multidisciplinary team.

The unresolved issues are long-term tumor control and the consequences of chemotherapy. Most of these patients are exposed to etoposide, which has been associated with secondary leukemia in patients without predisposition to cancer, but at modest rates when compared to the risk of EBRT in hereditary retinoblastoma. In a retrospective database and literature review, cases of secondary acute myeloid leukemia were identified among children who received epipodophyllotoxins. The actuarial risk for leukemia is not known and it is unclear whether the risk for children with retinoblastoma receiving topoisomerase II inhibitors exceeds the risk that exists for other children.[69]

Studies are planned for a variety of patient groups. The International Classification system is being utilized for these trials. This classification schema is based on the extent and location of intraocular retinoblastoma and is being used in the ongoing series of protocols from the COG. The preliminary version of this system was verified to be reproducible with preliminary data from five centers that staged their patients on an Internet site in August 2000. Experience with a closely related grouping system has been published.[2] Data have been published using this system in a study of chemotherapy for intraocular retinoblastoma, where stage appeared to assist in prognosis for successful treatment without enucleation or EBRT.[67]

The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI Web site.

• Delivery of chemotherapy via ophthalmic artery cannulation is being evaluated as an initial treatment for advanced unilateral and bilateral disease.

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with intraocular retinoblastoma. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI Web site.

1. Shields CL, Honavar SG, Meadows AT, et al.: Chemoreduction plus focal therapy for retinoblastoma: factors predictive of need for treatment with external beam radiotherapy or enucleation. Am J Ophthalmol 133 (5): 657-64, 2002.  [PUBMED Abstract]
   
   
2. Shields CL, Mashayekhi A, Demirci H, et al.: Practical approach to management of retinoblastoma. Arch Ophthalmol 122 (5): 729-35, 2004.  [PUBMED Abstract]
   
   
3. Shields CL, Meadows AT, Leahey AM, et al.: Continuing challenges in the management of retinoblastoma with chemotherapy. Retina 24 (6): 849-62, 2004.  [PUBMED Abstract]
   
   
4. Kim JW, Kathpalia V, Dunkel IJ, et al.: Orbital recurrence of retinoblastoma following enucleation. Br J Ophthalmol 93 (4): 463-7, 2009.  [PUBMED Abstract]
   
   
5. Krasin MJ, Crawford BT, Zhu Y, et al.: Intensity-modulated radiation therapy for children with intraocular retinoblastoma: potential sparing of the bony orbit. Clin Oncol (R Coll Radiol) 16 (3): 215-22, 2004.  [PUBMED Abstract]
   
   
6. Reisner ML, Viégas CM, Grazziotin RZ, et al.: Retinoblastoma--comparative analysis of external radiotherapy techniques, including an IMRT technique. Int J Radiat Oncol Biol Phys 67 (3): 933-41, 2007.  [PUBMED Abstract]
   
   
7. Lee CT, Bilton SD, Famiglietti RM, et al.: Treatment planning with protons for pediatric retinoblastoma, medulloblastoma, and pelvic sarcoma: how do protons compare with other conformal techniques? Int J Radiat Oncol Biol Phys 63 (2): 362-72, 2005.  [PUBMED Abstract]
   
   
8. Shields CL, Shields JA, Cater J, et al.: Plaque radiotherapy for retinoblastoma: long-term tumor control and treatment complications in 208 tumors. Ophthalmology 108 (11): 2116-21, 2001.  [PUBMED Abstract]
   
   
9. Merchant TE, Gould CJ, Wilson MW, et al.: Episcleral plaque brachytherapy for retinoblastoma. Pediatr Blood Cancer 43 (2): 134-9, 2004.  [PUBMED Abstract]
   
   
10. Shields CL, Mashayekhi A, Sun H, et al.: Iodine 125 plaque radiotherapy as salvage treatment for retinoblastoma recurrence after chemoreduction in 84 tumors. Ophthalmology 113 (11): 2087-92, 2006.  [PUBMED Abstract]
    
    
11. Shields CL, Santos MC, Diniz W, et al.: Thermotherapy for retinoblastoma. Arch Ophthalmol 117 (7): 885-93, 1999.  [PUBMED Abstract]
    
    
12. Friedman DL, Himelstein B, Shields CL, et al.: Chemoreduction and local ophthalmic therapy for intraocular retinoblastoma. J Clin Oncol 18 (1): 12-7, 2000.  [PUBMED Abstract]
    
    
13. Gündüz K, Shields CL, Shields JA, et al.: The outcome of chemoreduction treatment in patients with Reese-Ellsworth group V retinoblastoma. Arch Ophthalmol 116 (12): 1613-7, 1998.  [PUBMED Abstract]
    
    
14. Shields CL, Palamar M, Sharma P, et al.: Retinoblastoma regression patterns following chemoreduction and adjuvant therapy in 557 tumors. Arch Ophthalmol 127 (3): 282-90, 2009.  [PUBMED Abstract]
    
    
15. Lumbroso L, Doz F, Urbieta M, et al.: Chemothermotherapy in the management of retinoblastoma. Ophthalmology 109 (6): 1130-6, 2002.  [PUBMED Abstract]
    
    
16. Gombos DS, Kelly A, Coen PG, et al.: Retinoblastoma treated with primary chemotherapy alone: the significance of tumour size, location, and age. Br J Ophthalmol 86 (1): 80-3, 2002.  [PUBMED Abstract]
    
    
17. Abramson DH, Lawrence SD, Beaverson KL, et al.: Systemic carboplatin for retinoblastoma: change in tumour size over time. Br J Ophthalmol 89 (12): 1616-9, 2005.  [PUBMED Abstract]
    
    
18. Dunkel IJ, Lee TC, Shi W, et al.: A phase II trial of carboplatin for intraocular retinoblastoma. Pediatr Blood Cancer 49 (5): 643-8, 2007.  [PUBMED Abstract]
    
    
19. Wilson MW, Rodriguez-Galindo C, Haik BG, et al.: Multiagent chemotherapy as neoadjuvant treatment for multifocal intraocular retinoblastoma. Ophthalmology 108 (11): 2106-14; discussion 2114-5, 2001.  [PUBMED Abstract]
    
    
20. Rodriguez-Galindo C, Wilson MW, Haik BG, et al.: Treatment of intraocular retinoblastoma with vincristine and carboplatin. J Clin Oncol 21 (10): 2019-25, 2003.  [PUBMED Abstract]
    
    
21. Kingston JE, Hungerford JL, Madreperla SA, et al.: Results of combined chemotherapy and radiotherapy for advanced intraocular retinoblastoma. Arch Ophthalmol 114 (11): 1339-43, 1996.  [PUBMED Abstract]
    
    
22. Zage PE, Reitman AJ, Seshadri R, et al.: Outcomes of a two-drug chemotherapy regimen for intraocular retinoblastoma. Pediatr Blood Cancer 50 (3): 567-72, 2008.  [PUBMED Abstract]
    
    
23. Shields CL, Mashayekhi A, Cater J, et al.: Chemoreduction for retinoblastoma. Analysis of tumor control and risks for recurrence in 457 tumors. Am J Ophthalmol 138 (3): 329-37, 2004.  [PUBMED Abstract]
    
    
24. Wilson MW, Haik BG, Billups CA, et al.: Incidence of new tumor formation in patients with hereditary retinoblastoma treated with primary systemic chemotherapy: is there a preventive effect? Ophthalmology 114 (11): 2077-82, 2007.  [PUBMED Abstract]
    
    
25. Shields CL, Meadows AT, Shields JA, et al.: Chemoreduction for retinoblastoma may prevent intracranial neuroblastic malignancy (trilateral retinoblastoma). Arch Ophthalmol 119 (9): 1269-72, 2001.  [PUBMED Abstract]
    
    
26. Abramson DH, Frank CM, Dunkel IJ: A phase I/II study of subconjunctival carboplatin for intraocular retinoblastoma. Ophthalmology 106 (10): 1947-50, 1999.  [PUBMED Abstract]
    
    
27. Villablanca JG, Jubran R, Murphree AL: Phase I study of subtenon carboplatin I with systemic high dose carboplatin/etoposide/vincristine (CEV) for eyes with disseminated intraocular retinoblastoma (RB). [Abstract] Proceedings of the XIII Biannual Meeting of ISGED and the X International Symposium on Retinoblastoma, May 4, 2001, Fort Lauderdale, Fla. USA . 
    
    
28. Marr BP, Dunkel IJ, Linker A, et al.: Periocular carboplatin for retinoblastoma: long-term report (12 years) on efficacy and toxicity. Br J Ophthalmol 96 (6): 881-3, 2012.  [PUBMED Abstract]
    
    
29. Mallipatna AC, Dimaras H, Chan HS, et al.: Periocular topotecan for intraocular retinoblastoma. Arch Ophthalmol 129 (6): 738-45, 2011.  [PUBMED Abstract]
    
    
30. Muen WJ, Kingston JE, Robertson F, et al.: Efficacy and complications of super-selective intra-ophthalmic artery melphalan for the treatment of refractory retinoblastoma. Ophthalmology 119 (3): 611-6, 2012.  [PUBMED Abstract]
    
    
31. Gobin YP, Dunkel IJ, Marr BP, et al.: Intra-arterial chemotherapy for the management of retinoblastoma: four-year experience. Arch Ophthalmol 129 (6): 732-7, 2011.  [PUBMED Abstract]
    
    
32. Peterson EC, Elhammady MS, Quintero-Wolfe S, et al.: Selective ophthalmic artery infusion of chemotherapy for advanced intraocular retinoblastoma: initial experience with 17 tumors. J Neurosurg 114 (6): 1603-8, 2011.  [PUBMED Abstract]
    
    
33. Abramson DH, Marr BP, Dunkel IJ, et al.: Intra-arterial chemotherapy for retinoblastoma in eyes with vitreous and/or subretinal seeding: 2-year results. Br J Ophthalmol 96 (4): 499-502, 2012.  [PUBMED Abstract]
    
    
34. Bianciotto C, Shields CL, Iturralde JC, et al.: Fluorescein angiographic findings after intra-arterial chemotherapy for retinoblastoma. Ophthalmology 119 (4): 843-9, 2012.  [PUBMED Abstract]
    
    
35. Abramson DH, Dunkel IJ, Brodie SE, et al.: Superselective ophthalmic artery chemotherapy as primary treatment for retinoblastoma (chemosurgery). Ophthalmology 117 (8): 1623-9, 2010.  [PUBMED Abstract]
    
    
36. Shields CL, Bianciotto CG, Jabbour P, et al.: Intra-arterial chemotherapy for retinoblastoma: report No. 1, control of retinal tumors, subretinal seeds, and vitreous seeds. Arch Ophthalmol 129 (11): 1399-406, 2011.  [PUBMED Abstract]
    
    
37. Shields CL, Bianciotto CG, Jabbour P, et al.: Intra-arterial chemotherapy for retinoblastoma: report No. 2, treatment complications. Arch Ophthalmol 129 (11): 1407-15, 2011.  [PUBMED Abstract]
    
    
38. Shields CL, Kaliki S, Shah SU, et al.: Minimal exposure (one or two cycles) of intra-arterial chemotherapy in the management of retinoblastoma. Ophthalmology 119 (1): 188-92, 2012.  [PUBMED Abstract]
    
    
39. Suzuki S, Yamane T, Mohri M, et al.: Selective ophthalmic arterial injection therapy for intraocular retinoblastoma: the long-term prognosis. Ophthalmology 118 (10): 2081-7, 2011.  [PUBMED Abstract]
    
    
40. Levy C, Doz F, Quintana E, et al.: Role of chemotherapy alone or in combination with hyperthermia in the primary treatment of intraocular retinoblastoma: preliminary results. Br J Ophthalmol 82 (10): 1154-8, 1998.  [PUBMED Abstract]
    
    
41. Chantada GL, Guitter MR, Fandiño AC, et al.: Treatment results in patients with retinoblastoma and invasion to the cut end of the optic nerve. Pediatr Blood Cancer 52 (2): 218-22, 2009.  [PUBMED Abstract]
    
    
42. Eagle RC Jr: High-risk features and tumor differentiation in retinoblastoma: a retrospective histopathologic study. Arch Pathol Lab Med 133 (8): 1203-9, 2009.  [PUBMED Abstract]
    
    
43. Uusitalo MS, Van Quill KR, Scott IU, et al.: Evaluation of chemoprophylaxis in patients with unilateral retinoblastoma with high-risk features on histopathologic examination. Arch Ophthalmol 119 (1): 41-8, 2001.  [PUBMED Abstract]
    
    
44. Honavar SG, Singh AD, Shields CL, et al.: Postenucleation adjuvant therapy in high-risk retinoblastoma. Arch Ophthalmol 120 (7): 923-31, 2002.  [PUBMED Abstract]
    
    
45. Chantada GL, Dunkel IJ, de Dávila MT, et al.: Retinoblastoma patients with high risk ocular pathological features: who needs adjuvant therapy? Br J Ophthalmol 88 (8): 1069-73, 2004.  [PUBMED Abstract]
    
    
46. Cuenca A, Giron F, Castro D, et al.: Microscopic scleral invasion in retinoblastoma: clinicopathological features and outcome. Arch Ophthalmol 127 (8): 1006-10, 2009.  [PUBMED Abstract]
    
    
47. Chantada GL, Fandiño AC, Guitter MR, et al.: Results of a prospective study for the treatment of unilateral retinoblastoma. Pediatr Blood Cancer 55 (1): 60-6, 2010.  [PUBMED Abstract]
    
    
48. Kaliki S, Shields CL, Shah SU, et al.: Postenucleation adjuvant chemotherapy with vincristine, etoposide, and carboplatin for the treatment of high-risk retinoblastoma. Arch Ophthalmol 129 (11): 1422-7, 2011.  [PUBMED Abstract]
    
    
49. Shields CL, Shields JA: Editorial: chemotherapy for retinoblastoma. Med Pediatr Oncol 38 (6): 377-8, 2002.  [PUBMED Abstract]
    
    
50. Schouten-Van Meeteren AY, Moll AC, Imhof SM, et al.: Overview: chemotherapy for retinoblastoma: an expanding area of clinical research. Med Pediatr Oncol 38 (6): 428-38, 2002.  [PUBMED Abstract]
    
    
51. Shields CL, Gorry T, Shields JA: Outcome of eyes with unilateral sporadic retinoblastoma based on the initial external findings by the family and the pediatrician. J Pediatr Ophthalmol Strabismus 41 (3): 143-9; quiz 172-3, 2004 May-Jun.  [PUBMED Abstract]
    
    
52. Shields CL, Honavar SG, Meadows AT, et al.: Chemoreduction for unilateral retinoblastoma. Arch Ophthalmol 120 (12): 1653-8, 2002.  [PUBMED Abstract]
    
    
53. Zhao J, Dimaras H, Massey C, et al.: Pre-enucleation chemotherapy for eyes severely affected by retinoblastoma masks risk of tumor extension and increases death from metastasis. J Clin Oncol 29 (7): 845-51, 2011.  [PUBMED Abstract]
    
    
54. Chawla B, Sharma S, Sen S, et al.: Correlation between clinical features, magnetic resonance imaging, and histopathologic findings in retinoblastoma: a prospective study. Ophthalmology 119 (4): 850-6, 2012.  [PUBMED Abstract]
    
    
55. Beck MN, Balmer A, Dessing C, et al.: First-line chemotherapy with local treatment can prevent external-beam irradiation and enucleation in low-stage intraocular retinoblastoma. J Clin Oncol 18 (15): 2881-7, 2000.  [PUBMED Abstract]
    
    
56. Murphree AL, Villablanca JG, Deegan WF 3rd, et al.: Chemotherapy plus local treatment in the management of intraocular retinoblastoma. Arch Ophthalmol 114 (11): 1348-56, 1996.  [PUBMED Abstract]
    
    
57. Jubran RF, Murphree AL, Villablanca JG: Low dose carboplatin/etoposide/vincristine (CEV) and local therapy (LT) for intraocular retinoblastoma group II-IV eyes. [Abstract] Proceedings of the XIII Biannual Meeting of ISGED and the X International Symposium on Retinoblastoma, May 4, 2001, Fort Lauderdale, Fla. USA . 
    
    
58. Gallie BL, Budning A, DeBoer G, et al.: Chemotherapy with focal therapy can cure intraocular retinoblastoma without radiotherapy. Arch Ophthalmol 114 (11): 1321-8, 1996.  [PUBMED Abstract]
    
    
59. Chan HSL, Heon E, Budning A, et al.: Improvement of the cure rate of intraocular retinoblastoma without significantly increasing toxicity with higher dose carboplatin-teniposide in a cyclosporine multidrug resistance-reversal regimen. [Abstract] Proceedings of the XIII Biannual Meeting of ISGED and the X International Symposium on Retinoblastoma, May 4, 2001, Fort Lauderdale, Fla. USA . 
    
    
60. Villablanca JG, Atchaneeyasakul L, Murphree AL: Clinical outcome of group V eyes treated with cyclosporin A (CSA)/carboplatin/etoposide/vincristine (CEV). [Abstract] Proceedings of the XIII Biannual Meeting of ISGED and the X International Symposium on Retinoblastoma, May 4, 2001, Fort Lauderdale, Fla. USA . 
    
    
61. Chan HS, Gallie BL, Munier FL, et al.: Chemotherapy for retinoblastoma. Ophthalmol Clin North Am 18 (1): 55-63, viii, 2005.  [PUBMED Abstract]
    
    
62. Rodriguez-Galindo C, Chantada GL, Haik BG, et al.: Treatment of retinoblastoma: current status and future perspectives. Curr Treat Options Neurol 9 (4): 294-307, 2007.  [PUBMED Abstract]
    
    
63. Shields CL, Mashayekhi A, Cater J, et al.: Macular retinoblastoma managed with chemoreduction: analysis of tumor control with or without adjuvant thermotherapy in 68 tumors. Arch Ophthalmol 123 (6): 765-73, 2005.  [PUBMED Abstract]
    
    
64. Shields CL, Honavar SG, Shields JA, et al.: Factors predictive of recurrence of retinal tumors, vitreous seeds, and subretinal seeds following chemoreduction for retinoblastoma. Arch Ophthalmol 120 (4): 460-4, 2002.  [PUBMED Abstract]
    
    
65. Lumbroso-Le Rouic L, Aerts I, Lévy-Gabriel C, et al.: Conservative treatments of intraocular retinoblastoma. Ophthalmology 115 (8): 1405-10, 1410.e1-2, 2008.  [PUBMED Abstract]
    
    
66. Cohen VM, Kingston J, Hungerford JL: The success of primary chemotherapy for group D heritable retinoblastoma. Br J Ophthalmol 93 (7): 887-90, 2009.  [PUBMED Abstract]
    
    
67. Shields CL, Mashayekhi A, Au AK, et al.: The International Classification of Retinoblastoma predicts chemoreduction success. Ophthalmology 113 (12): 2276-80, 2006.  [PUBMED Abstract]
    
    
68. Chantada GL, Fandino AC, Carcaboso AM, et al.: A phase I study of periocular topotecan in children with intraocular retinoblastoma. Invest Ophthalmol Vis Sci 50 (4): 1492-6, 2009.  [PUBMED Abstract]
    
    
69. Gombos DS, Hungerford J, Abramson DH, et al.: Secondary acute myelogenous leukemia in patients with retinoblastoma: is chemotherapy a factor? Ophthalmology 114 (7): 1378-83, 2007.  [PUBMED Abstract]