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Managing Radiation Therapy Side Effects


Updated April 20, 2012

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

As one of the treatment modalities for colon cancer, radiation therapy is used to shrink tumors, reduce pain and stop cancer growth. Radiation therapy employs high doses of radiation, either internally or externally, to kill cancer cells. Unfortunately, healthy cells are also damaged during treatment, which can cause uncomfortable side effects. Although your healthcare team will watch for the most common side effects (and be prepared to treat them), the majority of this burden falls to you. You know your body best -- you may know when something is not right before your caregivers do.

Pelvic and Abdominal Radiation

Unlike chemotherapy, radiation is not a systemic (whole body) treatment. If you receive external beam radiation therapy, the radiation beam is focused on one specific area of your body. For traditional colon cancer treatment, the beam will be focused on your abdomen or pelvis, depending on the size and location of your cancer. The most common radiation side effects from abdominal and pelvic radiation therapy include:

  • Skin changes
  • Fatigue
  • Nausea, vomiting, diarrhea and appetite changes
  • Reproductive complications
  • Urinary and bladder changes

Although it is difficult to anticipate when (or if) you will experience one of these symptoms, most of them will resolve naturally during the months following your therapy.

Skin Changes

Skin irritation and peeling is a common side effect of radiation therapy and is well-anticipated by most radiation oncologists. During your treatment, you may experience:

  • Dry, itchy skin
  • Peeling, almost like a sunburn
  • Sensitivity
  • Sores or rashes

It's important to remember that your skin is taking a direct hit from the radiation every time you go for treatment. Take good care of your skin by:

  • Using mild soaps and unscented (or prescription) lotions
  • Avoiding direct sunlight (or a tanning bed) on the affected area
  • Bathing in lukewarm (not hot) water
  • Dry off using soft towels and patting, not rubbing
  • Do not scratch or pick at the area
  • Do not wash off the ink markings for therapy (sometimes they are tattooed on)


Second only to skin complaints, fatigue is the most common side effect experienced by people during radiation therapy. Many factors can influence your energy level alongside your therapy, including your diet, sleep quality, stress level and energy demands. Anticipate that you will feel a little tired during your therapy and adjust your work and social schedules accordingly. To boost waning energy, you can:

  • Get at least six to eight hours of uninterrupted sleep each night
  • Take a 30 minute nap when you are tired
  • Accept offers of help from friends and loved ones
  • Prioritize your activities and only complete necessary tasks
  • Conserve your energy for the things that are important to you
  • Limit your visitors and well-wishers until you feel better

Gastrointestinal Impacts

Following abdominal or pelvic radiation, you may experience side effects related to your gastrointestinal health. When the cells in your colon, small intestine or stomach are affected, you may experience:

  • Nausea and vomiting, especially following treatment
  • Decreasing or loss of appetite
  • Diarrhea

Although your doctor can prescribe medications to help curb these side effects, some simple dietary changes may help you in the meantime. If you have vomiting or diarrhea, make sure to drink plenty of water. Avoid caffeine as well (coffee, tea, cola) because it can further dehydrate you. If you suffer from nausea or your appetite is waning, try:

  • Avoiding dairy products
  • Limiting fatty, fried or greasy foods
  • Eating four to six smaller meals per day
  • Avoiding spicy foods
  • Snacking on bananas, applesauce, rice and toast for diarrhea
  • Having only a light snack or not eating for 4 hours prior to radiation

Reproductive Complications

For sigmoid colon or rectal cancers, pelvic radiation may be required. The organs of your reproductive system sit deep in your pelvis. When these cells are damaged, you may experience:

  • Hormonal fluctuations, leading to little or no desire for sexual activities
  • For men, difficulty or inability to gain an erection (impotence)
  • For men, low sperm count
  • For women, infertility
  • For women, vaginal dryness and pain

Based on your tumor location, your radiation oncologist will discuss your personal risk for developing any of these unwanted effects. The majority of reproductive side effects will resolve after radiation; however, continuing problems with infertility and hormonal changes may be a lifelong complication. If your doctor lists infertility as a side effect of your therapy, discuss alternative family planning measures, such as sperm banking for men or egg harvesting for women. Women need to use a form of birth control while on radiation therapy and notify the doctor immediately if you think you may be pregnant. In the meantime:

  • Openly discuss the sexual impacts of treatment with your partner
  • Women can use water-based lubricants for vaginal discomfort and dryness
  • Discuss other reproductive side effects with your physician -- in many cases, he or she can offer prescription medications to combat unwanted effects

Urinary and Bladder Symptoms

Your urinary tract and organs may get targeted by radiation therapy. There are many undesirable side effects due to cellular damage from the radiation. You may experience:

  • Difficulty or pain with urination
  • Frequency or urgency to go to the bathroom
  • Blood in urine and cramping

These uncomfortable effects may take up to three to five weeks to develop following therapy. Your doctor may order prescription medications to alleviate the symptoms after treatment. In the meantime, there are things you can to do decrease the severity of urinary symptoms:

  • Increase your water intake
  • Avoid caffeinated beverages, alcohol or tobacco
  • Talk to your doctor about blood in the urine or pain

Talk to Your Doctor

Report any side effects to your doctor, even if they were anticipated. This way, he or she can monitor the symptoms and may be able to help mitigate further exposure or unwanted cellular damage from radiation.


American Cancer Society. (2006). American Cancer Society's Complete Guide to Colorectal Cancer. Clifton Fields, NE: American Cancer Society.

Lange, V. (2009). Be a Survivor. Colorectal Cancer Treatment Guide. Los Angeles: Lange Productions.

Medline Plus. (n.d.). When You Have Nausea and Vomiting. Accessed April 15, 2012.

National Cancer Institute. (n.d.). Radiation Therapy and You. Accessed April 18, 2012.

Radiological Society of North America (n.d.). Colorectal Cancer. Accessed April 18, 2012.

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