What is chemoradiation for rectal cancer?

Chemoradiation is a combination of chemotherapy and radiotherapy. It is also sometimes called chemoradiotherapy.

Chemoradiation may be given:

  • before surgery to help shrink the cancer and reduce the risk of cancer coming back in or around the rectum
  • after surgery to reduce the risk of cancer coming back in or around the rectum

Chemotherapy drugs make cancer cells more sensitive to radiotherapy. The chemotherapy drugs most commonly used are fluorouracil (5FU) and capecitabine.

Fluorouracil (5FU) may be given into a vein as an injection with folinic acid, or as an infusion (drip). It’s usually given shortly before the radiotherapy. Your cancer doctor or nurse will tell you which days you’ll have fluorouracil.

Capecitabine is taken as tablets. You usually take them every day throughout the course of your radiotherapy.

Having chemotherapy and radiotherapy together can make the side effects of each treatment worse. Your doctor or specialist nurse can give you more information about chemoradiation and the possible side effects of this treatment.

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Making treatment decisions

Your doctors may tell you there are different options for your treatment. Having the right information will help you make the right decision for you.


Surgery involves removing all or part of the cancer with an operation. It is an important treatment for many cancers.


Chemotherapy uses drugs to treat many different types of cancer. It is most commonly given as an injection into a vein or as tablets or capsules.


Radiotherapy is the use of high-energy rays, usually x-rays and similar rays (such as electrons) to treat cancer.

Clinical trials

Many people are offered the chance to take part in a clinical trial as part of their treatment. Doctors also use clinical trials to improve cancer treatment and care.