If you have radiation to the pelvic area, the radiation therapists may advise you to drink fluids before each treatment. This will expand your bladder and push the bowel away from the radiation.
Even with precautions, radiation therapy can irritate the lining of the bowel or stomach and affect the way the bowel works. These changes are usually temporary, but for some people they are permanent and can have a major impact on quality of life. It is important to talk to your treatment team if you are finding bowel issues difficult to manage.
Learn more about:
Diarrhoea
This is when you have many loose, watery bowel motions. You may also have abdominal cramps, wind and pain. Towards the end of a course of radiation therapy to the abdomen or pelvic area, you may need to go to the toilet more urgently and more often. Having diarrhoea can be tiring, so rest as much as possible and ask others for help. Diarrhoea can take some weeks to settle down after treatment is over.
Radiation proctitis
Radiation therapy to the pelvic area can irritate the lining of the rectum, causing inflammation and swelling known as radiation proctitis. Symptoms may include blood and mucus in bowel motions; discomfort opening the bowels; or the need to empty the bowels often, perhaps with little result. Ask your radiation oncologist about your risk of developing radiation proctitis. It is usually short term but may be ongoing in a small number of people.
Bowel blockage
Rarely, after radiation therapy to the pelvis, especially if you have had previous abdominal surgery, you may develop a bowel blockage. This can be serious. It is important to let you doctor and treatment team know if you have pain in the abdomen, vomiting and difficulty opening your bowels.
How to manage bowel changes
- Ask your doctor about suitable medicines for diarrhoea. Take as directed.
- Check with your treatment team before taking any over-the-counter or home remedies, as taking them with anti-diarrhoea medicines may cause side effects.
- Drinking peppermint tea may reduce abdominal or wind pain.
- Continue to eat or drink. This is important to avoid weight loss and to give your body the nutrients it needs.
- Do some gentle exercise, such as walking, to encourage healthy bowel movements. Check with your doctor about the amount and type of exercise that is right for you.
- Try limiting caffeine from drinks such as tea, coffee, cola and other soft drinks. These can stimulate the bowel.
- Drink plenty of liquids when you first notice symptoms. This helps to avoid dehydration and replaces fluids lost through diarrhoea. Try apple juice, weak tea, clear broth, sports drinks and electrolyte‑replacing fluids. Switch to soy milk or lactose‑free milk for a period of time.
- Choose plain foods that are low in insoluble fibre (e.g. bananas, mashed potato, apple sauce, white rice or pasta, white bread, steamed white fish or chicken). Talk to your dietitian about what else you can eat.
- Avoid high‑fibre, fatty or fried foods; pulses; garlic and onion; and rich sauces and gravies, as these can make diarrhoea worse.
- Reduce sugar‑free or diet soft drinks and sweets that contain sorbitol, mannitol and xylitol as these can make diarrhoea worse.
- Contact your treatment team immediately if there is blood in your bowel motions or if you have more than 5–6 bowel movements in 24 hours.
Key resource
Download a PDF booklet on this topic.
More resources
A/Prof Susan Carroll, Senior Staff Specialist, Radiation Oncology, Royal North Shore Hospital, and The University of Sydney, NSW; Katie Benton, Advanced Dietitian Oncology, Sunshine Coast Hospital and Health Service, QLD; Adrian Gibbs, Director of Physics, Radiation Oncology, Princess Alexandra Hospital Raymond Terrace, QLD; Sinead Hanley, Consumer; Dr Annie Ho, Radiation Oncologist, GenesisCare, Macquarie University Hospital and St Vincent’s Hospital, NSW; Angelo Katsilis, Clinical Manager Radiation Therapist, Department of Radiation Oncology, Royal Adelaide Hospital, SA; Candice Kwet-On, 13 11 20 Consultant, Cancer Council Victoria; Jasmine Nguyen, Radiation Therapist, GenesisCare Hollywood, WA; Graham Rees, Consumer; Nicole Shackleton, Radiation Therapist, GenesisCare Murdoch, WA; Dr Tom Shakespeare, Director, Cancer Services, Mid North Coast Local Health District, NSW; Gabrielle Vigar, Nurse Lead, Cancer Program, Royal Adelaide Hospital and Queen Elizabeth Hospital, SA.
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