Colorectal Cancer

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Treating Colon/Rectum Cancer TOPICS

Chemotherapy for colorectal cancer

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

How is chemotherapy given?

Chemotherapy can be given in different ways.

Systemic chemotherapy: Systemic chemo uses drugs that are injected into a vein or given by mouth. These drugs enter the bloodstream and reach all areas of the body. This treatment is useful for cancers that have metastasized (spread) beyond the organ they started in.

Regional chemotherapy: In regional chemo, drugs are injected directly into an artery leading to a part of the body containing a tumor. This approach concentrates the dose of chemo reaching the cancer cells in that area. It reduces side effects by limiting the amount reaching the rest of the body.

Hepatic artery infusion, where chemo is given directly into the hepatic artery, is an example of regional chemotherapy sometimes used for colon cancer that has spread to the liver. This is used less often than systemic chemo.

When is chemo used?

Chemo may be used at different times during the treatment of colon or rectal cancers.

Adjuvant chemo: Chemo used after surgery to remove the cancer is known as adjuvant chemo. It can help keep the cancer from coming back later and has been shown to help people with stage II and stage III colon cancer and rectal cancer live longer. It is given after all visible cancer has been removed to lower the chance that it will come back. It works by killing the small number of cancer cells that may have been left behind at surgery because they were too small to see. Adjuvant chemo is also aimed at killing 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).

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 known as neoadjuvant treatment and is often used in treating rectal cancer.

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

Drugs used to treat colorectal cancer

Several drugs can be used to treat colorectal cancer. Often, 2 or more of these drugs are combined to try to make them more effective.

Chemo drugs are very strong medicines that can also affect some healthy cells in the body. Doctors give the drugs in cycles, with each period of treatment followed by a rest period to allow the body time to recover. Chemotherapy cycles generally last about 2 to 4 weeks, and people usually get at least several cycles of treatment. The drugs most often used for colorectal cancer include:

  • 5-Fluorouracil (5-FU), which is often given with the vitamin-like drug leucovorin (also called folinic acid), which makes it work better. (Because there is a national shortage of leucovorin, a similar drug called levo-leucovorin may be used instead.)
  • 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®)

Drugs and drug combinations often used to treat colon and rectal cancer

Common drug combinations used for adjuvant treatment include:

  • FOLFOX: 5-FU, leucovorin, and oxaliplatin
  • CapeOx: Capecitabine and oxaliplatin
  • 5-FU and leucovorin
  • Capecitabine

FOLFOX and CapeOx are considered stronger, but have more side effects.

For treatment of cancer that has spread, there are many options, including

  • FOLFOX: 5-FU, leucovorin, and oxaliplatin
  • FOLFIRI: 5-FU, leucovorin, and irinotecan
  • FOLFOXIRI (leucovorin, 5-FU, oxaliplatin, and irinotecan)
  • CapeOx: Capecitabine and oxaliplatin
  • 5-FU and leucovorin
  • Capecitabine
  • Irinotecan

Sometimes, these chemo drugs are given with a targeted therapy drug (discussed in the next section)

For rectal cancer, chemo with 5-FU or capecitabine combined with radiation may be given before surgery (neoadjuvant treatment).

Side effects of chemo

Chemo drugs work by attacking 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, the lining of the mouth and intestines, and the hair follicles, also divide quickly. These cells are also likely to be affected by chemo, which can lead to certain side effects.

The side effects of chemo depend on the type and dose of drugs given and the length of time they are taken. Common side effects drugs can include:

Chemo can affect the blood forming cells of the bone marrow, leading to low blood cell counts. This can lead to:

  • Increased chance of infections (too few white blood cells)
  • Easy bruising or bleeding (too few blood platelets)
  • Fatigue (too few red blood cells)

Along with these, some side effects are specific to certain medicines, for example:

Hand-foot syndrome can occur during treatment with capecitabine or 5-FU (when given as an infusion). This starts out as redness in the hands and feet, which can then progress to pain and sensitivity in the palms and soles. If it worsens, blistering or skin peeling can occur, sometimes leading to open, painful sores. It is 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 (painful nerve damage) is a common side effect of oxaliplatin. Symptoms include numbness, tingling, and even pain in the hands and feet. It can also cause patients to have intense sensitivity to hot and cold in the throat and esophagus (the tube connecting the throat to the stomach). This can cause problems (such as pain) swallowing liquids. 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.

Diarrhea 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®) many times. 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 side effects are short-term and tend to go away after treatment is finished. Some, such as hand and foot numbness, may persist for a long time. There are often ways to lessen these side effects. For example, drugs can be given to help prevent or reduce nausea and vomiting. Do not hesitate to discuss any questions about side effects with the cancer care team.

You should report any side effects or changes you notice while getting chemo to your medical team 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. There is no reason to withhold treatment in otherwise healthy people simply because of age.

For more information about any individual drug used for colorectal cancer treatment, please see our Cancer Drug Guide. For more general information about chemotherapy, please see our document Understanding Chemotherapy: A Guide for Patients and Families.


Last Medical Review: 07/30/2013
Last Revised: 01/31/2014