Chemotherapy is the use of drugs to control the cancer's growth or relieve symptoms. Often the drugs are given through a needle in your vein, and your blood vessels carry the drugs through your body. Sometimes the drugs are available as pills you can swallow. Sometimes they are given through a shot, or injection.

Several drugs are used to treat colorectal cancer. There are also several drugs available for treating side effects.

Medication Choices

A combination of drugs often works better than a single drug in treating colorectal cancer. The most commonly used drugs are:

• Fluorouracil (5-FU) combined with leucovorin.
• Fluorouracil (5-FU) combined with leucovorin and oxaliplatin.
• Capecitabine, sometimes combined with irinotecan or oxaliplatin.
• Oxaliplatin, sometimes combined with 5-FU.
• Irinotecan, sometimes combined with 5-FU.

Hair loss, a side effect common with some types of chemotherapy, is usually not a side effect of these drugs.

Treating the side effects

Your doctor may prescribe medicines that can help relieve side effects of chemotherapy. These side effects can include mouth sores, diarrhea, nausea, and vomiting. Your doctor may prescribe medicines to control nausea and vomiting. These drugs may include:

• Serotonin antagonists, such as ondansetron (Zofran), granisetron (Kytril), or dolasetron (Anzemet). These drugs more effectively prevent nausea and vomiting caused by chemotherapy when they are combined with corticosteroids, such as dexamethasone (Hexadrol).
• Aprepitant (Emend), which is used in combination with ondansetron and dexamethasone as part of a 3-day program.
• Antiemetics, such as promethazine hydrochloride (Phenergan) and prochlorperazine (Compazine).
• Metoclopramide (Reglan).

There also are things you can do at home to manage side effects. See the Home Treatment section for more information.

What To Think About

Chemotherapy and radiation may be combined to treat some types of colorectal cancer. Radiation or chemotherapy given before or after surgery can destroy microscopic areas of cancer to increase the chances of a cure. In some studies, people who had surgery and then were given the chemotherapy drugs fluorouracil (5-FU) and leucovorin lived longer.⁹

Clinical trials are designed to find better ways to treat people with cancer and are based on the most current information. Some people who meet the criteria for participation choose to enroll in such clinical trials.