Bowel late effects of pelvic radiotherapy

Pelvic radiotherapy often causes bowel symptoms. These usually get better within a few weeks of treatment ending. But some people have late effects that start months or years after treatment.

Talk to your cancer doctor or specialist nurse if you have:

  • side effects that do not go away
  • new symptoms or problems after treatment has ended.

If you have problems with your bowel, 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 see the following:

  • 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.

A few hospitals have clinics for people with late effects. Ask your healthcare team whether there are any near you. The Pelvic Radiation Disease Association may also be able to help you contact specialists.

For more information about the help available, contact the Macmillan Support Line free on 0808 808 00 00, 7 days a week, 8am to 8pm.

Bleeding from the rectum

Bleeding from the back passage (rectum) is common after pelvic radiotherapy.

Most people who have this side effect only notice bleeding occasionally. For a few people, bleeding can be heavy and needs 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.

We have more information about bleeding from the bowel after pelvic radiotherapy.

Bowel control problems

If you have a bowel control problem, you may have:

  • difficulty controlling when and how often you pass stools or wind
  • problems controlling your bowel, causing leakage or soiling (bowel incontinence), cramps, or bloating
  • diarrhoea or constipation
  • difficulty emptying your bowel completely.


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. The right 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 a week before you go to your appointment. Your doctor or nurse will usually ask you about:

  • your bowel habits and how they have changed
  • what your stools look like
  • your diet and lifestyle
  • any medicines you take
  • how the bowel problems are affecting your daily life.

This may include suggesting changes to your diet, or using medicines to regulate your bowel. They may give you advice about strengthening the muscles used for bowel control. We have more information about this.

Download our food and symptom diary (PDF).

Exercises for bowel control

Exercises to strengthen the muscles used in bowel control are called pelvic floor exercises. They may help with:

  • urgency
  • bowel incontinence
  • difficulty emptying your bowel completely
  • wind.

We have more information about pelvic floor exercises.


Many people find changing their diet and taking anti-diarrhoea drugs stops the 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 will be able to 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
  • exocrine pancreatic insufficiency (EPI).

We have more information about bowel changes after treatment.

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) to find out. If you have EPI, you will need a supplement to replace the enzymes. There are several different brands available. Supplements are made from pork. There are no vegetarian alternatives

The most commonly used supplement is a tablet called Creon®. It has been approved for use by Jewish patients by the Chief Rabbi. Previous rulings by Islamic scholars suggest that Muslims may use pork-based medicines if there is no alternative. 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.


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 (sit on the toilet in the right position)
  • check with your doctor if 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.

We have more information about constipation and bowel changes after treatment.


Tenesmus is the feeling that you need to go to the toilet but your bowel is empty. It can involve straining, pain and cramping. It can be caused by cramps (spasms) in the muscles that stimulate the bowel.

Tell your doctor or nurse if you have these symptoms.

We have more information about tenesmus.


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 Fyboge.

Try taking peppermint oil or charcoal tablets, or eating live yoghurts.

Tell your doctor if this symptom is a problem. Sometimes other things may be making wind worse. For example, constipation or bowel conditions, such as diverticular disease can make wind worse. Wind can also be a symptom of a food intolerance, or a condition called small bowel bacterial overgrowth after radiotherapy.

We have more information about bowel changes after bowel cancer treatment.

Sore or itchy skin

Ongoing diarrhoea or leaking (incontinence) 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, red or broken.

If your skin is sore or passing a bowel movement is painful, speak to your doctor or nurse. They can give you advice about looking after your skin and may give you creams or ointments to use. They can also check your skin for signs of other problems such as piles (haemorrhoids) or fissures.

Anal fissure

After 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 a stool (poo).

We have more information about anal fissure after pelvic radiotherapy.

Uncommon and rare late effects

Rarely, people may have the following problems because of pelvic radiotherapy.

  • Anal stricture

    Radiotherapy may cause a tight band of scar tissue at the opening of the back passage (anus). This makes the anus narrower. It is called an anal stricture. It can cause difficulty and pain when you try to empty your bowels.

    If it is mild, your doctor will advise you to take a stool-softening laxative or fibre supplement. This will make it easier to go to the toilet, which will help stretch the stricture.

    If the narrowing is more severe, your doctor can refer you to a specialist to talk about treatments that might help. You may be able to have a procedure to stretch the opening. This is called dilatation. Or you may have an operation under general anaesthetic to cut through the scar tissue. Your doctor or specialist nurse can explain more about these treatments.

  • Bowel blockage

    Signs of a blockage (obstruction) in the bowel may include:

    • severe pain or cramping in your tummy (abdomen)
    • sickness (vomiting)
    • 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 a 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.

  • Adhesions

    Normally, tissues and organs inside the tummy (abdomen) are slippery and move easily as the body moves. After surgery in the abdomen, bands of scar tissue (called adhesions) may form between abdominal tissues and organs, sticking them together.

    Adhesions often do not cause any problems. But sometimes they can cause pain.

    Rarely, adhesions can make part of the bowel twist or kink, pulling it out of place so that it becomes blocked.

    We have more information about adhesions.

  • Fistula

    A fistula is an opening that forms between areas of the body that are not usually connected. Rarely after pelvic radiotherapy or surgery for rectal or anal cancer, an opening can develop between:

    • the rectum and vagina
    • the rectum and bladder or urethra.

    Sometimes a fistula closes on its own. It can then be managed with treatment to control symptoms. If this does not happen, it may be possible to have an operation to close it.

    We have more information about fistulas.

About our information

  • References

    Below is a sample of the sources used in our pelvic radiotherapy information. If you would like more information about the sources we use, please contact us at

    Andreyev HJN, Muls AC, Norton C, et al. Guidance: The practical management of the gastrointestinal symptoms of pelvic radiation disease. Frontline Gastroenterology, 2015; 6, 53-72.

    Dilalla V, Chaput G, Williams T and Sultanem K. Radiotherapy side effects: integrating a survivorship clinical lens to better serve patients. Current Oncology, 2020; 27, 2, 107-112.

    The Royal College of Radiologists. Radiotherapy dose fractionation. Third edition. 2019. Available from: [accessed March 2021]. 

  • Reviewers

    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. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Date reviewed

Reviewed: 01 July 2021
Next review: 01 July 2024
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

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