Bowel problems after pelvic radiotherapy
Possible bowel late effects of pelvic radiotherapy
Pelvic radiotherapy often causes bowel symptoms. These usually get better within a few weeks after treatment has finished. But some people have late effects that start months or years after treatment.
Some people have mild symptoms that do not cause too many problems. They may only notice small changes, for others, bowel changes have a much bigger impact and can affect daily life. Bowel symptoms can affect your appetite or weight.
It is important that you get ongoing bowel symptoms checked by your doctor. You may feel embarrassed to talk about them. But doctors and nurses are used to speaking about these issues. If they know you are having problems, they can answer your questions and help you.
Some people with late effects need help from other specialists. Your doctor or nurse can refer you to a specialist if needed. For example, you may meet with the following healthcare professionals:
- a gastroenterologist – a doctor who treats problems with the digestive system.
- a colorectal surgeon – a doctor who does operations (surgery) on the large bowel.
- a continence advisor – a specialist nurse or physiotherapist who gives advice and support to people with continence problems (such as leakage or soiling).
Some hospitals in the UK have special clinics for people with late effects from radiotherapy. Ask your healthcare team or GP whether there are any near you. Your doctor or nurse can refer you to other specialists if needed.
The Pelvic Radiation Disease Association also has information about support and late effects services.
For more information about the help available, contact the Macmillan Support Line free on 0808 808 00 00.
Bleeding from the rectum
Bleeding from the back passage (rectum) is common after pelvic radiotherapy.
Most people who have bleeding from the rectum only notice bleeding occasionally. For a few people, bleeding can be heavy and they will need treatment.
Even if you think you know the cause, always tell your doctor or specialist nurse if you have any bleeding from the back passage.
Bowel control problems
If you have a bowel control problem, you may have:
- difficulty controlling when and how often you pass stools (poo) or wind
- problems controlling your bowel, leading to incontinence (leakage or soiling), cramps, or bloating
- diarrhoea
- constipation
- difficulty emptying your bowel completely.
Tests
Your doctor or nurse will usually ask about your bowel problems and things that affect your symptoms. It is important that they properly assess your situation. Treatments for bowel control problems depend on your symptoms and what is causing them.
We have information about the tests you may have to check for bowel problems.
It may be helpful to record your bowel habits and what you eat for 1 week before you go to your appointment. Your doctor or nurse will usually ask you about:
- how your bowel habits have changed
- what your stools look like
- your diet and lifestyle
- any medicines you take
- how the bowel problems are affecting your daily life.
They will probably have helpful suggestions for improving bowel control including, changes to your diet and drugs to regulate your bowel.
Download our food and symptom diary (PDF).
Exercises for bowel control
Exercises for strengthening the muscles used for bowel control are called pelvic floor exercises. They may help with urgency, bowel incontinence, difficulty emptying your bowel completely and wind.
Diarrhoea
Many people find changing their diet and taking anti-diarrhoea drugs stops diarrhoea. But if this does not help, ask your doctor to refer you to a gastroenterologist. Lots of different things can cause diarrhoea, and a gastroenterologist can do a full assessment.
After bowel cancer treatment, particularly pelvic radiotherapy, some people have diarrhoea caused by changes to the small bowel, such as:
- bile acid malabsorption – also called bile acid diarrhoea
- small bowel bacterial overgrowth – also called small intestinal bacterial overgrowth (SIBO).
- exocrine pancreatic insufficiency (EPI).
Exocrine pancreatic insufficiency (EPI)
This condition sometimes develops in people who have had pelvic radiotherapy to an area of the body that includes para-aortic lymph nodes. These are close to the pancreas. This type of radiotherapy is sometimes used to treat cervical cancer or womb cancer.
The pancreas makes proteins called enzymes. These help to digest food. EPI develops when the pancreas does not make enough enzymes to digest food properly. This can mean you are not getting enough nutrients. It can cause weight loss. Symptoms of EPI include:
- diarrhoea
- painful cramps
- stools (poo) that are pale and difficult to flush.
If your doctor thinks you might have EPI, they can arrange for you to have a stool test (faecal elastase test). If you have EPI, you will need a supplement to replace the enzymes. Several different brands of supplement are available. They are made from pork. There are no vegetarian alternatives
The most commonly used supplement is a tablet called Creon®. Previous rulings by Islamic scholars suggest that Muslims may use pork-based medicines if there is no alternative. It has been approved for use by Jewish patients by the Chief Rabbi. If you have concerns about this, speak to your religious leader.
You will need to take the supplement with everything you eat or drink. Most people with pancreatic insufficiency do not absorb enough vitamins and minerals. You may also need a multi-vitamin and mineral supplements. A dietitian will be able to help you use the tablets correctly, as it is important to take enough of the supplements.
Constipation
If you have problems with constipation after treatment, the following tips may help:
- include more fibre in your diet
- drink at least 1 to 2 litres (2 to 3½ pints) of fluid a day
- do daily exercise, such as walking
- get into a toilet routine
- use the correct toilet posture – this means sitting on the toilet in the right position
- check with your doctor whether you are taking medicines that can cause constipation
- take medicines to treat constipation.
If the constipation gets worse or you have severe tummy (abdominal) pain, get advice from your doctor or nurse.
Wind
If you have problems with wind after bowel cancer treatment, the following tips may help:
- Cut down on foods and drinks that are causing wind.
- Eat your meals at the same times each day.
- Do not eat and drink at the same time.
- Use pelvic floor exercises to strengthen the muscles used for bowel control.
- Ask your doctor for advice if you take medicines that cause wind, such as Lactulose® or Fybogel®.
- Some people find taking peppermint oil or eating live yoghurt can help.
Tell your doctor if wind is a problem. Sometimes other things may be making wind worse – for example, constipation or bowel conditions such as diverticular disease. Wind can also be a symptom of a food intolerance or a condition called small bowel bacterial overgrowth after radiotherapy.
Sore or itchy skin
Ongoing diarrhoea or incontinence (leakage from the bowel) can make the skin around the anus sore. Sometimes radiotherapy for rectal or anal cancer can also make this area of skin sore or broken.
Tell your doctor or nurse if your skin is sore or passing stools (pooing) is painful. They can give you advice about looking after your skin. They may give you creams or ointments to use. They can also check your skin for signs of other problems such as haemorrhoids (piles) or fissures.
Uncommon and rare late effects
Rarely, people may have the following problems because of pelvic radiotherapy.
- Anal stricture – after pelvic radiotherapy, the skin of the anus may become narrower and less stretchy. Sometimes a split develops in the skin of the anus. This is called an anal fissure. It can cause a sharp, intense pain when you pass stools (poo).
- Bowel blockage – signs may include vomiting (being sick), bloating, loud gurgling sounds from the bowel, tummy swelling, inability to pass wind, constipation. If you have severe pain, you should contact a doctor straight away.
You may need tests such as x-rays or a CT scan to check what is causing the pain. If your symptoms are caused by a blocked bowel, you may need urgent treatment. - Hole in the bowel wall – very rarely, a hole may develop in the bowel wall. This is called a perforated bowel. It can make you feel suddenly unwell. This is usually treated straight away with an operation to remove the affected part of the bowel.
About our information
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.
-
References
Below is a sample of the sources used in our late effects of pelvic radiotherapy information. If you would like more information about the sources we use, please contact us at informationproductionteam@macmillan.org.uk
S Haas, A Højer Mikkelsen, C Jensenius Skovhus Kronborg et al. Management of treatment-related sequelae following colorectal cancer. PubMed. Colorectal Disease Journal. 15 August 2022. Available at https://pubmed.ncbi.nlm.nih.gov/35969031/ [accessed March 2026]V Sun, C Wendal,W Demark-Wahnefried et al. Diet and Behaviour Modifications by Long-Term Rectal Cancer Survivors to Manage Bowel Dysfunction-Associated Symptoms. PubMed. Nutrition and Cancer. 2020 January. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6456395/ [accessed March 2026]
A Carlile and T McAdam. The Long-Term and Late Effects of the Diagnosis and Treatment of Colorectal Cancer. Ulster Medical Journal. 2023 May. Available at https://pubmed.ncbi.nlm.nih.gov/37649914/ [accessed March 2026]
Date reviewed
Our cancer information meets the PIF TICK quality mark.
This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.
The language we use
We want everyone affected by cancer to feel our information is written for them.
We want our information to be as clear as possible. To do this, we try to:
- use plain English
- explain medical words
- use short sentences
- use illustrations to explain text
- structure the information clearly
- make sure important points are clear.
We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.
You can read more about how we produce our information here.