Difficulty passing urine after pelvic radiotherapy
Sometimes pelvic radiotherapy can affect the pelvic floor muscles. It may also cause changes to the urethra or nerves that control the bladder.
Difficulty passing urine (retention)
If you are having problems passing urine (peeing), or feel that you are not emptying your bladder completely, it is important to see your doctor. If urine builds up in the bladder, it can cause infections and damage the kidneys.
Your doctor or continence adviser will do tests to find out the cause so they can offer you the right treatment for your situation.
Sometimes, difficulty passing urine can be caused by the pelvic floor muscles being unable to relax. Pelvic radiotherapy can cause this. Less often, it can be caused by changes to the urethra or nerves that control the bladder.
Related pages
Urethral stricture
Pelvic radiotherapy can sometimes cause the urethra to become narrow. This can make it more difficult to pass urine. This narrowing is caused by scar tissue. It is called a urethral stricture.
Treating small stricture
Possible treatments for small stricture include:
- Urethral dilatation – this is where tubes are passed through the urethra to widen (dilate) it. You may have this treatment under a general or local anaesthetic. It may need to be repeated.
- Urethrotomy – this is where the surgeon passes a tube with a light on the end (a cystoscope) into the urethra. Small cuts are made to widen the urethra. You may have a catheter for a couple of days to let the urethra heal.
You may have this operation under a spinal anaesthetic, where you are awake but do not feel anything from the waist down. Or you may have a general anaesthetic.
Treating larger stricture
A larger stricture may be treated with an operation called a urethroplasty. This is an operation that uses tissue from another part of the body to repair the urethra.
Your specialist doctor can tell you what the most suitable treatment may be in your individual situation.
Related pages
Nerve damage
Sometimes, pelvic radiotherapy can damage the nerves to the bladder. The nerve damage means the bladder muscles cannot squeeze strongly enough. This can mean the bladder does not empty completely. This is called urinary retention.
Some people may need to use a catheter to empty their bladder a few times a day. This is called intermittent self-catheterisation. Your specialist or urology specialist or continence advisor can tell you more about this.
Getting expert help
There are different ways to manage or treat bladder symptoms. Your GP can advise you or refer you to a specialist healthcare professional. This might be a urologist, continence advisor or physiotherapist.
The right treatment for you will depend on the symptoms or side effect you have and how much of a problem they are.
Getting support
Macmillan is here to support you. If you would like to talk, you can do the following:
- Call the Macmillan Support Line on 0808 808 00 00.
- Chat to our specialists online.
- Visit our cancer treatment forum to talk with people who have had cancer treatment, share your experience, and ask an expert your questions.
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.
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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
Urinary incontinence and pelvic organ prolapse in women: management. National Institute for Health and Care Excellence. (NICE) guideline Reference number:NG123 Published: 02 April 2019 Last updated: 24 June 2019. Available at www.nice.org.uk/guidance/ng123 [accessed March 2026]
R Dalsania, K Shah, E Stotsky-Himelfarb, S Hoffe et al. Management of Long-Term Toxicity from Pelvic Radiation Therapy. Gastrointestinal cancer- Colorectal and anal. Ascopubs April 2021. Available at https://ascopubs.org/doi/pdf/10.1200/EDBK_323525 [accessed March 2026]
C Helissey, S Cavallero, C Brossard et al. Chronic Inflammation and Radiation-Induced Cystitis: Molecular Background and Therapeutic Perspectives. PubMed. 2020 Dec 24;10 Available at https://pubmed.ncbi.nlm.nih.gov/33374374/ [accessed March 2026]
LUTS in men. National Institute for Health and Care Excellence. (NICE) Last revised in June 2025. Available at https://cks.nice.org.uk/topics/luts-in-men/ [accessed March 2026]
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