Chemotherapy in Colon Cancer.
Chemotherapy is the use of drugs to kill cancer cells, often by inhibiting their ability to proliferate and divide. Systemic chemotherapy is administered through the bloodstream to the extent that cancer cells throughout the body. Chemotherapy is usually administered by a medical oncologist, a doctor who specializes in treating cancer with medication. A therapeutic regimen (schedule) usually consists of a chemotherapy specific number of cycles that are administered in a given time period.Generally, chemotherapy for colorectal cancer is injected directly into a vein, but can also be administered in pill form. A patient may receive one drug at a time or combinations of different drugs at the same time.
Chemotherapy may be given after surgery to kill any remaining cancer cells. In some people with rectal cancer, the doctor will administer chemotherapy and radiation therapy before surgery to shrink a tumor of the rectum and decrease the chance of the cancer returning.
Currently, there are seven approved drugs in the United States by the Food and Drug Administration (U.S. Food and Drug Administration, FDA) to treat colorectal cancer. Your doctor may recommend one or more of them at different stages during treatment. These drugs are: fluorouracil (5-FU, Adrucil), capecitabine (Xeloda), irinotecan (Camptosar), oxaliplatin (Eloxatin), bevacizumab (Avastin), cetuximab (Erbitux) and panitumumab (Vectibix). (The last three are described in “targeted therapy”, see below). Some common treatments are:
- 5-FU with leucovorin (Wellcovorin), a vitamin that improves the effectiveness of 5-FU
- Capecitabine, a form of 5-FU oral administration
- 5-FU with leucovorin and oxaliplatin (FOLFOX called)
- 5-FU with leucovorin and irinotecan (FOLFIRI called)
- Irinotecan alone
- Capecitabine with irinotecan or oxaliplatin
- Any of the above, cetuximab or bevacizumab
Chemotherapy can cause vomiting, nausea, diarrhea, or mouth sores. However, there are medications to prevent these side effects. The way in which drugs are administered, side effects are less severe than in the past for most patients. In addition, patients may feel too tired and there is a greater risk of contracting an infection.With some drugs, can also occur neuropathy (tingling or numbness in the feet or hands). Hair loss is a rare side effect with drugs used to treat colorectal cancer. Medications are available to alleviate most of the side effects such as nausea, diarrhea and neuropathy. If side effects are particularly difficult, you can reduce the dose of the drug or postpone a treatment session. Patients should talk with the health care team to understand when side effects requiring medical consultation. The side effects of chemotherapy usually go away after treatment ends.
Medications used to treat cancer are continually being evaluated. Often, talk with your doctor is the best way to get information about the medications prescribed, their purpose and possible side effects or interactions with other medications.