Chemotherapy (chemo) is treatment with anti-cancer drugs that may be injected into a vein or taken by mouth. These drugs travel through the bloodstream and reach most parts of the body. Chemo is often used to treat colorectal cancer.
Chemo may be used at different times during treatment for colorectal cancer:
- Adjuvant chemo is given after surgery. The goal is to kill cancer cells that might 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 colon or rectal cancer to settle 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 is given (sometimes with radiation) before surgery to try to shrink the cancer and make it easier to remove. This is often done for rectal cancer.
- For advanced cancers that have spread to other organs like the liver, chemo can be used to help shrink tumors and ease problems they're causing. While it's not likely to cure the cancer, this often helps people feel better and live longer.
How is chemotherapy given?
You can get chemotherapy in different ways to treat colorectal cancer.
- Systemic chemotherapy: Drugs are put right into your blood through a vein or you take them by mouth. The drugs enter your bloodstream and reach almost all areas of your body.
- Regional chemotherapy: Drugs are put right into an artery that leads to the part of the body with the cancer. This focuses the chemo on 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.
Chemo drugs for colon or rectal cancer that are given into a vein (IV), can be given either as an injection over a few minutes or as an infusion over a longer period of time. This can be done in a doctor’s office, infusion center, or in a hospital setting.
Often, a slightly larger and sturdier IV is required in the vein system to administer chemo. These are known as central venous catheters (CVCs), central venous access devices (CVADs), or central lines. They are used to put medicines, blood products, nutrients, or fluids right into your blood. They can also be used to take blood for testing.There are many different kinds of CVCs. The most common types are the port and the PICC line.
Chemo is given in cycles, followed by a rest period to give you time to recover from the effects of the drugs. Cycles are most often 2 or 3 weeks long. The schedule varies depending on the drugs used. For example, with some drugs, the chemo is given only on the first day of the cycle. With others, it is given for a few days in a row, or once a week. Then, at the end of the cycle, the chemo schedule repeats to start the next cycle.
Adjuvant or neoadjuvant chemo is often given for a total of 3 to 6 months, depending on the drugs used. The length of treatment for advanced colorectal cancer depends on how well it is working and what side effects you have.
Chemotherapy drugs used to treat colorectal cancer
Some drugs commonly used for colorectal cancer include:
- 5-Fluorouracil (5-FU)
- Capecitabine (Xeloda), a pill that is changed into 5-FU once it gets to the tumor.
- Irinotecan (Camptosar)
- Oxaliplatin (Eloxatin)
- Trifluridine and tipiracil (Lonsurf), a combination drug in pill form
Most often, combinations of 2 or 3 of these drugs are used. Sometimes, chemo drugs are given along with a targeted therapy drug.
Possible 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 hair follicles and in the lining of the mouth and intestines, 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 can include:
- Hair loss
- Mouth sores
- Loss of appetite or weight loss
- Nausea and vomiting
- Nail changes
- Skin changes
Chemo can also affect the blood-forming cells of the bone marrow, which can lead to:
- Increased chance of infections (from low white blood cell counts)
- Easy bruising or bleeding (from low blood platelet counts)
- Fatigue (from low red blood cell counts and other reasons)
Other side effects are specific to certain drugs. Ask your cancer care team about the possible side effects of the specific drugs you are getting. For example:
- Hand-foot syndrome can develop during treatment with capecitabine or 5-FU (when given as an infusion). It can start out as redness in the hands and feet, and then might progress to pain and sensitivity in the palms and soles. If it worsens, the skin may blister or peel, 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) 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 cold in your throat, esophagus (the tube connecting the throat to the stomach), and the palms of your hands. This can cause pain when swallowing cold liquids or holding a cold glass. If you'll be getting oxaliplatin, talk with your doctor about side effects beforehand, and let them know right away if you develop numbness and tingling or other side effects.
- Allergic or sensitivity reactions can happen in some people 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're getting chemo.
- Diarrhea is a common side effect with many of these chemo 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 a drug like loperamide (Imodium). If you're getting a chemo drug that will likely cause diarrhea, your doctor will give you instructions on what drugs to take and how often to take them to control this problem.
Most of these side effects tend to go away over time after treatment ends. 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 or you may be told to keep ice chips in your mouth while chemo is being given to lower the chances of getting mouth sores.
Be sure to discuss any questions about side effects with your cancer care team. Also report any side effects or changes you notice while getting chemo so that they can be treated right away. In some cases, the doses of the chemo drugs may need to be reduced or treatment may need to be delayed or stopped to help keep the problem from getting worse.
Older people seem to be able to tolerate some types of chemo for colon or rectal cancer fairly well. Age is no reason to withhold treatment in otherwise healthy people.