What is radiation therapy for colon cancer?

Radiation therapy sends high doses of radiation to cancer cells and is one of the most common treatments for cancer. Unlike chemotherapy, it only affects the part of the body that is being treated. It can be used alone or with other treatments like surgery or chemotherapy.

Do I need radiation to treat colon cancer?

Radiation for colon cancer is often used:

  • After surgery to kill any remaining cancer cells
  • To control the symptoms of the cancer in patients who are not healthy enough for surgery
  • To treat cancer that has spread to other areas of the body 

What is radiation treatment like with colon cancer?

Radiation can be given in different ways; sometimes, more than one type is used. Your doctor will decide which type is best for your cancer depending on your specific situation.


  • Directs high-energy rays from outside the body into the tumor


  • Also called brachytherapy
  • Uses a radioactive source that is put inside the body, in or near the tumor


  • Uses radioactive drugs (either by pill or IV) during the embolization procedure

How long will I have to go for radiation with colon cancer?

Radiation treatments vary for each person. Your treatment may require you to go daily over a period of several days, weeks or months, but each session often takes less than 30 minutes.

What are the side effects of radiation with colon cancer?

Side effects vary from person to person. Some people will not have them. The most common side effects of radiation include:

  • Fatigue
  • Skin irritation
  • Hair loss
  • Blood in the urine
  • Sexual problems

It is important to talk to your doctor about your side effects if they affect your daily routine.