Side effects during/soon after treatment (Early or ‘acute’ side effects)

General – Fatigue is quite common in the second half of treatment and is very variable between patients. It may be worse for men on both hormone therapy and radiation therapy. Fatigue can persist for a few weeks after treatment, but as for other early side effects, this has usually settled within 4-6 weeks after radiation therapy is completed.

Local – All other side effects of radiation therapy come from the structures/organs in and just next to where the radiation is being targeted. For the prostate this means the bottom of the bladder, the urethra (the tube through the prostate where urine passes) and the front part of the rectum (lower bowel). These can commonly cause the following side effects, which usually have fully settled by 4- 6 weeks after treatment is finished.

Bladder/urethra – in weeks 3-4 of treatment it is common to start to get some or all of the following: increased frequency of urine, especially at night; stinging or burning while passing urine; a sense of not fully emptying the bladder; a poorer stream than before. These symptoms are usually mild to moderate but can be worse if there were significant urinary problems before treatment.

Rectum – Bowel motions may become more frequent in the second half of treatment or there may be a need to go more frequently or urgently to open the bowels. There may be some more mucous discharge, excess wind and/or discomfort on opening bowels. Diarrhoea is very uncommon.

What can help reduce side effects?

Resting as needed can help with fatigue though some men find regular exercise helps as well. During treatment patients are given advice about their bowels and bladder and are encouraged to drink plenty of water especially in the earlier part of the day and to keep the motions soft and easy to pass. Over the counter medicines can help with burning and stinging when passing urine. If bowel symptoms are more severe, suppositories can be prescribed by the doctor but this is quite unusual with modern radiation therapy. These side effects are rarely severe with modern targeted radiation therapy and commonly settle soon after treatment.

Side effects well after treatment (Late or long-term side effects)

Local side effects

Bladder/urethra – Incontinence is very rare after radiation therapy alone but is more common when combined with surgery. Tightening of the urethra with scarring (stricturing) occurs in about 2-3% of men having radiation therapy alone. Bleeding from abnormal blood vessels in the bladder as a result of previous radiation therapy is not common but is seen in some cases, and needs to be investigated to exclude things like bladder cancer.

Rectal (lower bowel) changes from radiation therapy can cause (usually minor) change in bowel habit, excess mucus production, or bleeding in <10% of men (though this does not necessarily occur all the time). These symptoms can be severe enough to significantly impact on long term quality of life less than 5% of the time.

Sexual function (erections) can be reduced over time after radiation therapy (more so if men are on hormone treatments), especially if there were issues before treatment. For men with ‘normal’ sexual function pre-treatment, erections can be negatively affected over time in around half of all cases, although there may be many other factors that affect erectile function. The volume of the ejaculate and quality of the orgasm can reduce. Fertility is affected negatively in most men, but sperm storage can be organised pre-treatment in those men who have not yet completed a family.

Any exposure to radiation increases the risk of a second cancer developing in that area, usually decades later. This risk is not entirely attributable to radiation received as part of your treatment. All X-rays and scans received over your lifetime contribute to this risk, as does unavoidable exposure to environmental radiation. The risk of a cancer being caused by radiotherapy is in the order of 0.5 – 1% at 10 years.

What can be done to treat late side effects?

Bleeding from the bladder or rectum can be treated with techniques that use laser to close up bleeding blood vessels if this problem persists. This is especially effective for rectal bleeding. Dietary measures can help if the bowel actions become more urgent or frequent over the longer term. Stretching of urethral strictures by a urologist can alleviate a weakened urine stream. Medical treatments can be used to improve erections after a discussion with your doctor (tablets and/or penile injections).

Information and Guidance

Radiotherapy Treatment Process

Click below for a video that shows the external beam radiotherapy treatment process.