Blood in the urine after pelvic radiotherapy

Pelvic radiotherapy can cause long-term changes to the way the bladder works. The bladder lining may bleed easily and can cause blood in your urine.

About blood in the urine

Pelvic radiotherapy can damage the nerves that control the bladder muscles. Another side effect is it may also narrow the tube that carries urine out of the body (the urethra).

Pelvic radiotherapy can cause blood in the urine (haematuria). This is because radiotherapy can damage the tissue and blood vessels in the lining of the bladder. They can become weaker, and bleed more easily.

If you have blood in the urine, it is likely you will need to have tests. This is because there are other reasons for blood in the urine, such as infection, and it is important to rule these out.

You may have a test called a cystoscopy, where a thin tube with a camera and light on the end is used to look inside your bladder. During the cystoscopy, the doctor may decide to treat the bleeding using heat to seal the blood vessels (called cauterisation or diathermy). This can be done with an electrical current or a laser.

Treating blood in the urine

If there is only a small amount of bleeding that has been caused by radiotherapy, you may not need any treatment. But if the bleeding is regular or heavy, or you become anaemic (have a low number of red blood cells), you are likely to need treatment.

Possible treatments include:

  • Tablets

    Tranexamic acid (Cyklokapron®) tablets can reduce bleeding.

    Your doctor may prescribe you these tablets for a short time There is a slightly increased risk of having a blood clot with tranexamic acid. You can discuss this with your doctor before taking the tablets.

  • Bladder wash-out

    If you are passing blood clots in your urine, these may need to be flushed out to make sure they do not block your urethra. A nurse or doctor slowly passes liquid through a catheter into your bladder with a syringe. Then the liquid is gently drawn back out with the syringe, or drains back out of the catheter into a bag. This can be repeated until the clots have gone.

    Sometimes a catheter with an extra opening can be used. This means a bag of fluid can be attached which goes through the catheter. The fluid washes clots out of your bladder and drains into a catheter bag. This is called bladder irrigation.

    A bladder wash-out can also be done during a cystoscopy if the catheter methods have been tried before.

  • Treating anaemia

    Some people become anaemic because of bleeding from the bladder. Anaemia is when you do not have enough red blood cells to carry oxygen around the body. This can make you feel breathless or tired. Your doctor may suggest you take iron tablets, which will help you make red blood cells. This will improve your symptoms and make you feel better. Some people may need a blood transfusion. 

    We have more information about blood transfusions.

If bladder problems do not improve

If your bladder symptoms continue or do not improve after having these treatments, your specialist may talk to you about other possibilities. When symptoms are severe, an operation to remove the bladder may be an option, but this is very rare.

We have information about coping with bladder or bowel problems.

Getting support

Macmillan is here to support you. If you would like to talk, you can do the following:

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.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.