Treatment for colon cancer is based largely on the stage (extent) of the cancer, but other factors can also be important.
People with colon cancers that have not spread to distant sites usually have surgery as the main or first treatment. Chemotherapy may also be used after surgery (called adjuvant treatment). Most adjuvant treatment is given for about 6 months.
Since stage 0 colon cancers have not grown beyond the inner lining of the colon, surgery to take out the cancer is often the only treatment needed. In most cases this can be done by removing the polyp or taking out the area with cancer through a colonoscope (local excision). Removing part of the colon (partial colectomy) may be needed if a cancer is too big to be removed by local excision.
Stage I colon cancers have grown deeper into the layers of the colon wall, but they have not spread outside the colon wall itself or into the nearby lymph nodes.
Stage I includes cancers that were part of a polyp. If the polyp is removed completely during colonoscopy, with no cancer cells at the edges (margins) of the removed piece, no other treatment may be needed.
If the cancer in the polyp is high grade , or there are cancer cells at the edges of the polyp, more surgery might be recommended. You might also be advised to have more surgery if the polyp couldn’t be removed completely or if it had to be removed in many pieces, making it hard to see if cancer cells were at the edges.
For cancers not in a polyp, partial colectomy ─ surgery to remove the section of colon that has cancer and nearby lymph nodes ─ is the standard treatment. You typically won't need any more treatment.
Many stage II colon cancers have grown through the wall of the colon, and maybe into nearby tissue, but they have not spread to the lymph nodes.
Surgery to remove the section of the colon containing the cancer (partial colectomy) along with nearby lymph nodes may be the only treatment needed. But your doctor may recommend adjuvant chemotherapy (chemo after surgery) if your cancer has a higher risk of coming back (recurring) because of certain factors, such as:
The doctor might also test your tumor for specific gene changes, called MSI or MMR, to help decide if adjuvant chemotherapy would be helpful.
Not all doctors agree on when chemo should be used for stage II colon cancers. It’s important for you to discuss the risks and benefits of chemo with your doctor, including how much it might reduce your risk of recurrence and what the likely side effects will be.
If chemo is used, the main options include 5-FU and leucovorin, oxaliplatin, or capecitabine, but other combinations may also be used.
Stage III colon cancers have spread to nearby lymph nodes, but they have not yet spread to other parts of the body.
Surgery to remove the section of the colon with the cancer (partial colectomy) along with nearby lymph nodes, followed by adjuvant chemo is the standard treatment for this stage.
For chemo, either the FOLFOX (5-FU, leucovorin, and oxaliplatin) or CapeOx (capecitabine and oxaliplatin) regimens are used most often, but some patients may get 5-FU with leucovorin or capecitabine alone based on their age and health needs.
For some advanced colon cancers that cannot be removed completely by surgery, neoadjuvant chemotherapy given along with radiation (also called chemoradiation) might be recommended to shrink the cancer so it can be removed later with surgery. For some advanced cancers that have been removed by surgery, but were found to be attached to a nearby organ or have positive margins (some of the cancer may have been left behind), adjuvant radiation might be recommended. Radiation therapy and/or chemo may be options for people who aren’t healthy enough for surgery.
Stage IV colon cancers have spread from the colon to distant organs and tissues. Colon cancer most often spreads to the liver, but it can also spread to other places like the lungs, brain, peritoneum (the lining of the abdominal cavity), or to distant lymph nodes.
In most cases surgery is unlikely to cure these cancers. But if there are only a few small areas of cancer spread (metastases) in the liver or lungs and they can be removed along with the colon cancer, surgery may help you live longer. This would mean having surgery to remove the section of the colon containing the cancer along with nearby lymph nodes, plus surgery to remove the areas of cancer spread. Chemo is typically given after surgery, as well. In some cases, hepatic artery infusion may be used if the cancer has spread to the liver.
If the metastases cannot be removed because they're too big or there are too many of them, chemo may be given before surgery (neoadjuvant chemo). Then, if the tumors shrink, surgery may be tried to remove them. Chemo might be given again after surgery. For tumors in the liver, another option may be to destroy them with ablation or embolization.
If the cancer has spread too much to try to cure it with surgery, chemo is the main treatment. Surgery might still be needed if the cancer is blocking the colon or is likely to do so. Sometimes, such surgery can be avoided by putting a stent (a hollow metal tube) into the colon during a colonoscopy to keep it open. Otherwise, operations such as a colectomy or diverting colostomy (cutting the colon above the level of the cancer and attaching the end to an opening in the skin on the belly to allow waste out) may be used.
If you have stage IV cancer and your doctor recommends surgery, it’s very important to understand the goal of the surgery ─ whether it's to try to cure the cancer or to prevent or relieve symptoms of the cancer.
Most people with stage IV cancer will get chemo and/or targeted therapies to control the cancer. Some of the most commonly used regimens include:
The choice of regimens depends on several factors, including any previous treatments you’ve had and your overall health.
If one of these regimens is no longer working, another may be tried.
For people whose cancer cells have changes in certain genes or proteins, targeted therapy drugs might be an option.
For people whose cancers cells have high levels of microsatellite instability (MSI) or changes in one of the MMR genes, an option after initial chemotherapy might be treatment with an immunotherapy drug such as pembrolizumab (Keytruda) or nivolumab (Opdivo).
For advanced cancers, radiation therapy can also be used to help prevent or relieve symptoms in the colon from the cancer such as pain. It might also be used to treat areas of spread such as in the lungs or bone. It may shrink tumors for a time, but it's not likely to cure the cancer. If your doctor recommends radiation therapy, it’s important that you understand the goal of treatment.
Recurrent cancer means that the cancer has come back after treatment. The recurrence may be local (near the area of the initial tumor), or it may be in distant organs.
If the cancer comes back locally, surgery (often followed by chemo) can sometimes help you live longer and may even cure you. If the cancer can’t be removed surgically, chemo might be tried first. If it shrinks the tumor enough, surgery might be an option. This might be followed by more chemo.
If the cancer comes back in a distant site, it's most likely to appear in the liver first. Surgery might be an option for some people. If not, chemo may be tried to shrink the tumor(s), which may then be followed by surgery to remove them. Ablation or embolization techniques might also be an option to treat some liver tumors.
If the cancer has spread too much to be treated with surgery, chemo and/or targeted therapies may be used. Possible treatment schedules are the same as for stage IV disease.
For people whose cancers are found to have certain gene changes, another option might be treatment with immunotherapy.
Your options depend on which, if any, drugs you had before the cancer came back and how long ago you got them, as well as your overall health. You may still need surgery at some point to relieve or prevent blockage of the colon or other local problems. Radiation therapy may be an option to relieve symptoms as well.
Recurrent cancers can often be hard to treat, so you might also want to ask your doctor if clinical trials of newer treatments are available.
For more on recurrence, see Understanding Recurrence.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
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National Cancer Institute. Physician Data Query (PDQ). Colon Cancer Treatment. 2020. Accessed at https://www.cancer.gov/types/colorectal/patient/colorectal-treatment-pdq on February 20, 2020.
National Comprehensive Cancer Network (NCCN). NCCN Clinical Practice Guidelines in Oncology: Colon Cancer. V.3.2022. Accessed at https://www.nccn.org/professionals/physician_gls/pdf/colon.pdf on January 20, 2023.
Last Revised: January 26, 2023
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