This page was reviewed under our medical and editorial policy by
Gagandeep Brar, MD, Medical Oncologist And Hematologist, City of Hope | Duarte
This page was reviewed on June 2, 2023.
Chemotherapy involves the use of certain specific types of medicine to treat cancer, including colorectal cancer. Here’s how it works and what to expect.
Your cancer team may recommend chemotherapy at different times during colorectal cancer treatment, depending on the other treatments you may need as part of your plan:
Adjuvant chemotherapy is given after cancer surgery. Its purpose is to eradicate remaining cancer cells left behind, and it may help reduce the possibility of cancer returning.
Neoadjuvant chemotherapy is given before surgery to make tumors smaller and easier for your surgeon to remove. In such cases, radiation therapy may be given in addition to chemotherapy. Rectal cancer patients are more likely to have neoadjuvant chemotherapy.
With advanced cancer that has spread to other areas of the body, chemotherapy may help reduce tumor size and help you feel better.
Chemotherapy for colorectal cancer is given in different ways, depending on a number of factors:
Systemic chemotherapy is administered to the entire body. These drugs may be given through a vein, or you might take them by mouth.
Regional chemotherapy is administered via an artery close to the area affected by cancer. This may lead to fewer side effects and help more specifically target the cancer cells in that designated area.
Chemoembolization of the hepatic artery, also called hepatic arterial infusion—or sometimes referred to as a chemotherapy pump—is a treatment for colorectal cancer that has spread to the liver. Chemoembolization blocks the main blood supply to the liver (the hepatic artery) so that anti-cancer drugs can be injected between that area and the liver. The drugs will then remain mainly in the liver. Sometimes this blockage is temporary, but it may also be permanent.
Adjuvant or neoadjuvant chemotherapy is typically given over a period of three to six months. This is often broken up into cycles, which are periods when you’ll receive the drugs followed by time to rest and recover from the drugs’ effects. Each chemotherapy cycle usually lasts a couple weeks. The exact treatment time depends on the specific drugs given. For instance, you may receive chemotherapy only on the first day of a two- to three-week cycle, or you may get it once a week or over a couple of days. Then, after the break, another cycle begins.
Several types of drugs are used for colorectal cancer. Your care team may recommend using more than one chemotherapy drug. They also may advise using a targeted therapy drug along with chemotherapy.
The most common drugs used during chemotherapy for colorectal cancer, sometimes in combination, include:
Chemotherapy drugs may cause side effects, but they aren’t as severe as they used to be, and certain medications and strategies are available to help manage them.
The most common side effects of chemotherapy drugs include:
Some side effects from chemotherapy are specific to the type of medication used:
Allergic reactions or sensitivity: Let your care team know if you develop reactions such as a skin rash, dizziness or trouble breathing. These reactions are often associated with oxaliplatin.
Diarrhea: Although several chemotherapy drugs may cause diarrhea, it can be particularly challenging with irinotecan. That’s why your team will likely recommend a drug or other steps that may help control it. Diarrhea may lead to dangerous dehydration if left unchecked.
Hand-foot syndrome: Signs are blistering, swelling and redness that may develop on the hands and feet with certain types of chemotherapy. For colorectal cancer patients, the condition is specifically associated with capecitabine or 5-FU given as an infusion. Talk with your care team as soon as you notice any such symptoms so that they can help treat this reaction.
Neuropathy: Commonly described as tingling or numbness in the hands and feet, neuropathy may also lead to cold sensitivity in your throat and hands. It’s often associated with oxaliplatin. Let your team know if you experience any of these symptoms.
Side effects from chemotherapy usually go away when treatment stops. If medications that prevent or treat them aren’t helping, talk to your care team about other steps you can take, such as delaying the next cycle or possibly reducing the chemotherapy dosage.