The colon is part of the body's digestive system. The digestive system takes in nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) from foods and helps pass waste material out of the body. The digestive system is made up of the esophagus, stomach, and the small and large intestines. The colon (large bowel) is the main part of the large intestine and is about 5 feet long. Together, the rectum and anal canal make up the last part of the large intestine and are about 6 to 8 inches long. The anal canal ends at the anus (the opening of the large intestine to the outside of the body).
Gastrointestinal stromal tumors can occur in the colon. For more information, visit Gastrointestinal Stromal Tumors Treatment.
Colorectal cancer is caused by certain changes to the way colorectal cells function, especially how they grow and divide into new cells. There are many risk factors for colorectal cancer, but many do not directly cause cancer. Instead, they increase the chance of DNA damage in cells that may lead to colorectal cancer. To learn more about how cancer develops, see What Is Cancer?
A risk factor is anything that increases the chance of getting a disease. Some risk factors for colorectal cancer, like smoking, can be changed. However, risk factors also include things you cannot change, like your genetics, getting older, and your family history. Learning about risk factors for colorectal cancer can help you make changes that might lower your risk of getting it.
Risk factors for colorectal cancer include:
Older age is a main risk factor for most cancers. The chance of getting cancer increases as you get older.
Having one or more of these risk factors does not mean that you will get colorectal cancer. Many people with risk factors never develop colorectal cancer, while others with no known risk factors do. Talk with your doctor if you think you might be at increased risk.
These and other signs and symptoms may be caused by colon cancer or by other conditions. Check with your doctor if you have:
In addition to asking about your personal and family health history and doing a physical exam, your doctor may perform the following tests and procedures:
There are two types of FOBTs:
The process used to find out whether cancer has spread within the colon or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment.
The following tests and procedures may be used in the staging process:
You may want to get a second opinion to confirm your colon cancer diagnosis and treatment plan. If you seek a second opinion, you will need to get medical test results and reports from the first doctor to share with the second doctor. The second doctor will review the pathology report, slides, and scans. They may agree with the first doctor, suggest changes or another treatment approach, or provide more information about your cancer.
Learn more about choosing a doctor and getting a second opinion at Finding Cancer Care. You can contact NCI’s Cancer Information Service via chat, email, or phone (both in English and Spanish) for help finding a doctor, hospital, or getting a second opinion. For questions you might want to ask at your appointments, visit Questions to Ask Your Doctor About Cancer.
The prognosis and treatment options depend on:
Cancer stage describes the extent of cancer in the body, such as the size of the tumor, whether it has spread, and how far it has spread from where it first formed. It is important to know the stage of the colon cancer to plan the best treatment.
There are several staging systems for cancer that describe the extent of the cancer. Colon cancer staging usually uses the TNM staging system. The cancer may be described by this staging system in your pathology report. Based on the TNM results, a stage (I, II, III, or IV, also written as 1, 2, 3, or 4) is assigned to your cancer. When talking to you about your diagnosis, your doctor may describe the cancer as one of these stages.
Learn about tests to stage colon cancer. Learn more about Cancer Staging.
In stage 0 colon cancer, abnormal cells are found in the mucosa (innermost layer) of the colon wall. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.
In stage I colon cancer, cancer has formed in the mucosa (innermost layer) of the colon wall and has spread to the submucosa (layer of tissue next to the mucosa) or to the muscle layer of the colon wall.
Stage II colon cancer is divided into stages IIA, IIB, and IIC.
Stage III colon cancer is divided into stages IIIA, IIIB, and IIIC.
In stage IIIA, cancer has spread:
In stage IIIB, cancer has spread:
In stage IIIC, cancer has spread:
Stage IV colon cancer is divided into stages IVA, IVB, and IVC.
Stage IV colon cancer is also called metastatic colon cancer. Metastatic cancer happens when cancer cells travel through the lymphatic system or blood and form tumors in other parts of the body. The metastatic tumor is the same type of cancer as the primary tumor. For example, if colon cancer spreads to the liver, the cancer cells in the liver are actually colon cancer cells. The disease is called metastatic colon cancer, not liver cancer. Learn more in Metastatic Cancer: When Cancer Spreads.
Recurrent colon cancer is cancer that has come back after it has been treated. If colon cancer comes back, it may come back in the colon or in other parts of the body, such as the liver, lungs, or both. Tests will be done to help determine where the cancer has returned. The type of treatment for recurrent colon cancer will depend on where it has come back.
Learn more in Recurrent Cancer: When Cancer Comes Back. Information to help you cope and talk with your health care team can be found in the booklet When Cancer Returns.
Different types of treatments are available for colon cancer. You and your cancer care team will work together to decide your treatment plan, which may include more than one type of treatment. Many factors will be considered, such as the stage of the cancer, your overall health, and your preferences. Your plan will include information about your cancer, the goals of treatment, your treatment options and the possible side effects, and the expected length of treatment.
Talking with your cancer care team before treatment begins about what to expect will be helpful. You’ll want to learn what you need to do before treatment begins, how you’ll feel while going through it, and what kind of help you will need. To learn more, visit Questions to Ask Your Doctor About Treatment.
Surgery is the most common treatment for all stages of colon cancer. The cancer is removed using one of the following types of surgery:
Radiation therapy and/or chemotherapy may be given before surgery to shrink the tumor, make it easier to remove the cancer, and help with bowel control after surgery. Treatment given before surgery is called neoadjuvant therapy. After all the cancer that can be seen at the time of the surgery is removed, some patients may be given radiation therapy and/or chemotherapy after surgery to kill any cancer cells that are left. Treatment given after the surgery, to lower the risk that the cancer will come back, is called adjuvant therapy.
If the cancer has spread to the liver and cannot be removed by surgery, a total hepatectomy and liver transplant after chemotherapy may be done. Total hepatectomy and liver transplant is the removal of the entire liver by surgery, followed by a transplant of a healthy liver from a donor.
Chemotherapy (also called chemo) uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing.
Systemic chemotherapy is when chemotherapy drugs are taken by mouth or injected into a vein or muscle. When given this way, the drugs enter the bloodstream and can reach cancer cells throughout the body. Systemic chemotherapy used to treat colon cancer includes:
Combinations of these drugs may be used. Other chemotherapy drugs not listed here may also be used.
Chemotherapy may also be combined with other kinds of drugs. For example, it might be combined with the targeted therapy drug bevacizumab, cetuximab, or panitumumab.
Regional chemotherapy for colon cancer is when drugs are placed directly into the hepatic artery (the main artery that supplies blood to the liver) in a procedure called chemoembolization. Chemoembolization of the hepatic artery may be used to treat cancer that has spread to the liver. This is done by blocking the hepatic artery and injecting anticancer drugs between the blockage and the liver. The liver’s arteries then carry the drugs into the liver. Only a small amount of the drug reaches other parts of the body. The blockage may be temporary or permanent, depending on what is used to block the artery. The liver continues to receive some blood from the hepatic portal vein, which carries blood from the stomach and intestine.
The way the chemotherapy is given depends on the type and stage of the cancer being treated.
Learn more about how chemotherapy works, how it is given, common side effects, and more at Chemotherapy to Treat Cancer and Chemotherapy and You: Support for People With Cancer.
Radiation therapy uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. Colon cancer is sometimes treated with two types of radiation therapy used to treat colon cancer:
Learn more about Radiation Therapy to Treat Cancer and Radiation Therapy Side Effects.
Targeted therapy uses drugs or other substances to identify and attack specific cancer cells. Your doctor may suggest biomarker tests to help predict your response to certain targeted therapy drugs. Learn more about Biomarker Testing for Cancer Treatment.
Targeted therapies used to treat colon cancer include:
Learn more about Targeted Therapy to Treat Cancer.
Immunotherapy helps a person’s immune system fight cancer. Your doctor may suggest biomarker tests to help predict your response to certain immunotherapy drugs. Learn more about Biomarker Testing for Cancer Treatment.
Immunotherapy drugs used to treat colon cancer include:
Learn more about Immunotherapy to Treat Cancer.
For some people, joining a clinical trial may be an option. There are different types of clinical trials for people with cancer. For example, a treatment trial tests new treatments or new ways of using current treatments. Supportive care and palliative care trials look at ways to improve quality of life, especially for those who have side effects from cancer and its treatment.
You can use the clinical trial search to find NCI-supported cancer clinical trials accepting participants. The search allows you to filter trials based on the type of cancer, your age, and where the trials are being done. Clinical trials supported by other organizations can be found on the ClinicalTrials.gov website.
Learn more about clinical trials, including how to find and join one, at Clinical Trials Information for Patients and Caregivers.
For information about side effects caused by treatment for cancer, visit our Side Effects page.
As you go through treatment, you will have follow-up tests or check-ups. Some tests that were done to diagnose or stage the cancer may be repeated to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests.
Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back).
After treatment for colon cancer, a blood test to measure amounts of carcinoembryonic antigen (a substance in the blood that may be increased when cancer is present) may be done to see if the cancer has come back.
Treatment of stage 0 may include the following types of surgery:
Learn more about these treatments in the Treatment Option Overview.
Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.
Treatment of stage I colon cancer and stage II colon cancer may include resection and anastomosis.
Learn more about these treatments in the Treatment Option Overview.
Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.
Treatment of stage III colon cancer may include resection and anastomosis, which may be followed by chemotherapy.
Learn more about these treatments in the Treatment Option Overview.
Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.
Treatment of stage IV colon cancer, recurrent colon cancer, and liver metastasis may include:
Treatment of cancer that has spread to the liver may also include:
Learn more about these treatments in the Treatment Option Overview.
Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.
For more information from the National Cancer Institute about colon cancer, visit:
For general cancer information and other resources from the National Cancer Institute, visit:
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PDQ® Adult Treatment Editorial Board. PDQ Colon Cancer Treatment. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/types/colorectal/patient/colon-treatment-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389319]
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