Chemotherapy for Colorectal Cancer

Chemotherapy (chemo) is treatment with anti-cancer drugs.

How is chemotherapy given?

You can get chemotherapy in different ways.

Systemic chemotherapy: Drugs are injected into your vein or you take them by mouth. These drugs enter your bloodstream and reach all areas of your body. 

Regional chemotherapy: Drugs are injected directly into an artery that leads to a part of the body with a tumor. This method concentrates the dose of chemo reaching the cancer cells in that area. It reduces side effects by limiting the amount of drug reaching the rest of your body. Hepatic artery infusion, or chemo given directly into the hepatic artery, is an example of regional chemotherapy sometimes used for cancer that has spread to the liver. 

Doctors give chemo in cycles, with each period of treatment followed by a rest period to give the body time to recover. Chemotherapy cycles generally last about 2 to 4 weeks, and people usually get at least several cycles of treatment.

When is chemotherapy used for colorectal cancer?

Chemo may be used at different times during treatment for colorectal cancer.

Adjuvant chemo: Chemo can be given after surgery. The goal is to kill any cancer cells that may have been left behind at surgery because they were too small to see, as well as cancer cells that might have escaped from the main tumor and settled in other parts of the body (but are too small to see on imaging tests). This helps lower the chance that the cancer will come back.

Neoadjuvant chemo: For some cancers, chemo is given (sometimes with radiation) before surgery to try to shrink the cancer and make surgery easier. This is often used in treating rectal cancer.

Chemo for advanced cancers: For cancers that have spread to other organs, such as the liver, chemo can also be used to help shrink tumors and relieve symptoms. Although it is not likely to cure the cancer, it often helps people live longer.

Drugs used to treat colorectal cancer

Some common drugs used for colorectal cancer include:

  • 5-Fluorouracil (5-FU), which is often given with the vitamin-like drug leucovorin (also called folinic acid) or a similar drug called levo-leucovorin, which helps it work better.
  • Capecitabine (Xeloda), which is in pill form. Once in the body, it is changed to 5-FU when it gets to the tumor site.
  • Irinotecan (Camptosar)
  • Oxaliplatin (Eloxatin)
  • Trifluridine and tipiracil (Lonsurf), a combination drug in pill form

Often, 2 or more of these drugs are combined to try to make them more effective. Sometimes, chemo drugs are given along with a targeted therapy drug.

Side effects of chemo

Chemo drugs attack cells that are dividing quickly, which is why they work against cancer cells. But other cells in the body, such as those in the bone marrow (where new blood cells are made), the lining of the mouth and intestines, and the hair follicles, are also dividing quickly. These cells can be affected by chemo too, which can lead to side effects.

The side effects of chemo depend on the type and dose of drugs given and how long you take them. Common side effects of chemo drugs can include:

  • Hair loss
  • Mouth sores
  • Loss of appetite
  • Nausea and vomiting
  • Diarrhea
  • Increased chance of infections (from having too few white blood cells)
  • Easy bruising or bleeding (from having too few blood platelets)
  • Fatigue (from having too few red blood cells)

Along with these, some side effects are specific to certain drugs. For example:

  • Hand-foot syndrome. During treatment with capecitabine or 5-FU (when given as an infusion), this can start out as redness in the hands and feet, and then progress to pain and sensitivity in the palms and soles. If it worsens, blistering or skin peeling can occur, sometimes leading to painful sores. It’s important to tell your doctor right away about any early symptoms, such as redness or sensitivity, so that steps can be taken to keep things from getting worse.
  • Neuropathy (nerve damage). This is a common side effect of oxaliplatin. Symptoms include numbness, tingling, and even pain in the hands and feet. It can also cause intense sensitivity to hot and cold in your throat, esophagus (the tube connecting the throat to the stomach), and the palms of your hands. This can cause problems swallowing liquids or holding a cold glass. If you will be getting oxaliplatin, talk with your doctor about side effects beforehand, and let him or her know right away if you develop numbness and tingling or other side effects.
  • Allergic or sensitivity reactions. Some people can have reactions while getting the drug oxaliplatin. Symptoms can include skin rash, chest tightness and trouble breathing, back pain, or feeling dizzy, lightheaded, or weak. Be sure to tell your nurse right away if you notice any of these symptoms while you are getting chemo.
  • Diarrhea. This is a common side effect with many of these drugs, but can be particularly bad with irinotecan. It needs to be treated right away — at the first loose stool — to prevent severe dehydration. This often means taking drugs like loperamide (Imodium). If you are on a chemo drug that is likely to cause diarrhea, your doctor will give you instructions on what drugs to take and how often to take them to control this symptom.

Most of these side effects tend to go away after treatment is finished. Some, such as hand and foot numbness from oxaliplatin, may last for a long time. There are often ways to lessen these side effects. For example, you can be given drugs to help prevent or reduce nausea and vomiting.

Be sure to discuss any questions about side effects with your cancer care team, and report any side effects or changes you notice while getting chemo so that they can be treated promptly. In some cases, the doses of the chemo drugs may need to be reduced or treatment may need to be delayed or stopped to prevent the effects from getting worse.

Older people seem to be able to tolerate some types of chemo for colorectal cancer fairly well. Age is no reason to withhold treatment in otherwise healthy people.

To learn more about chemo, see the Chemotherapy section on our website.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master's-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

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Last Medical Review: January 15, 2017 Last Revised: March 2, 2017

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