Pelvic radiotherapy side effects

Pelvic radiotherapy can cause side effects during and after treatment. Your radiographer or nurse will give you advice or medicines to help manage them.

Side effects during pelvic radiotherapy

Pelvic radiotherapy destroys cancer cells in the area where it is given. It can also damage some normal cells. This may cause side effects.

Side effects do not usually happen straight away. They may develop during your course of treatment or in the days or weeks after treatment finishes. After you finish radiotherapy, the effects may get worse for a time before they get better.

You may have a small risk of long-term side effects. Side effects can sometimes also start months or years after radiotherapy. These are called late effects.

You are unlikely to get all the possible side effects of radiotherapy. The side effects you have may depend on:

Having chemotherapy at the same time as radiotherapy is called chemoradiation. This may cause more severe side effects.

Your radiotherapy team will explain what to expect. Always tell them if you have side effects during or after radiotherapy. They can give advice and support to help you cope.

You may also find it helpful to read our information about the type of cancer you have. This has more detail about your treatment and the other possible side effects.

Stopping smoking

If you smoke, try to stop. Research shows that stopping smoking during and after radiotherapy may help it work better. It may also help to reduce the risk of some types of cancer coming back. Stopping smoking can also help to reduce many of the side effects of pelvic radiotherapy. Your radiotherapy team, GP or a pharmacist can give you information about stopping smoking.


Radiotherapy usually makes people feel tired. Tiredness may get worse as treatment goes on. If you are having radiotherapy alongside other treatments, such as surgery or chemotherapy, you may feel more tired. But there are things you can do to help, such as:

  • getting plenty of rest
  • doing some gentle exercise, such as short walks
  • eating a healthy diet and drinking plenty of fluids
  • asking others for help with everyday jobs.

After treatment finishes, you may continue to feel tired for weeks or months. If it does not get better, tell your cancer doctor or specialist nurse

We have more information about coping with tiredness (fatigue).

Effects on the skin

Pelvic radiotherapy can cause a skin reaction in the area being treated. This can be uncomfortable, particularly in sensitive areas. These areas may include:

  • the anus
  • the vulva
  • the penis
  • the scrotum
  • either side of the groin
  • between the buttocks.

If a skin reaction happens, it usually starts after about 10 to 14 days of treatment. Your skin may become red or get darker in the area having treatment. It may also feel warm, itchy or sore. Sometimes the skin gets very sore and may blister, break or leak fluid.

Your radiographer or nurse will check your skin regularly. Tell them if your skin is sore, or if you notice any other changes during or after radiotherapy. They will give you advice about managing it. They may give you dressings or creams to help. They can also give you painkillers if you need them.

Skin reactions can take time to improve. They are usually worst in the first 2 weeks after treatment finishes. They then start to get better as the skin heals.

Pelvic radiotherapy may make your pubic hair fall out. It usually starts to grow back a few weeks after you finish radiotherapy, but it may be thinner. Sometimes hair loss is permanent.

Skin care

Your radiographers or nurse will explain how to care for your skin during pelvic radiotherapy. They may give the following advice:

  • Have showers rather than baths if you can. Use a gentle stream of lukewarm water. If you have a bath, do not use very hot water. Try not to soak in the water for longer than a few minutes, as it can make your skin too moist.
  • Wear loose underwear or shorts made from natural fibres, such as cotton or silk. Avoid tight-fitting clothes that may rub against your skin.
  • Do not shave, wax or use hair removal creams in the treatment area during radiotherapy. Wait until a few weeks after radiotherapy has finished and any skin reaction has healed.
  • Protect the treated area from the sun for the first year after radiotherapy. You should do this even after any skin reaction has improved. Always wear suncream with a sun protection factor (SPF) of at least 30.

Follow your radiotherapy team’s advice about using soaps, moisturisers, creams and deodorants. This may vary depending on your hospital.

Bladder side effects

Pelvic radiotherapy can irritate the lining of the bladder. This can cause side effects such as:

Coping with bladder side effects

Always tell your radiotherapy team if you have any side effects during or after your treatment. They will give you advice and may recommend medicines to help you feel more comfortable. They may also ask you for a urine sample to check if you have an infection. An infection is a common cause of symptoms and is easy to treat.

Contact the hospital straight away if:

  • your symptoms get worse
  • you have a high temperature
  • you feel you cannot pass urine.

Your radiotherapy team can advise you about coping with any bladder problems. If the problems do not improve within a few weeks, they may arrange tests. Or they may get more advice for you from a specialist.

People often feel embarrassed talking about bladder problems. But telling your doctor, radiographers or nurse means they can give you advice and support to help manage your symptoms.

There are some things you can do that may help with bladder side effects:

  • Try to drink plenty of fluids. If your urine is dark and concentrated, it can irritate the bladder and make symptoms worse. Drinking more makes your urine paler and less concentrated. Aim to drink at least 2 to 3 litres (3½ to 5½ pints) of fluids a day.
  • Try to drink more water and less of drinks that may irritate the bladder. These include drinks containing caffeine, such as tea, coffee, drinking chocolate and cola. Try to limit alcohol, fizzy drinks, acidic drinks (for example, orange or grapefruit juice) and drinks with artificial sweeteners (for example, diet or ‘light’ drinks).
  • Try drinking cranberry juice or taking cranberry capsules to help reduce symptoms. But do not have cranberry products if you take a drug called warfarin.

We have more information on coping with bladder changes.

Other urinary problems

If your treatment involves the prostate or penis, it may also cause swelling around the urethra. This is the tube that carries urine from the bladder, through the prostate, to the opening at the tip of the penis.

This can cause side effects such as:

  • passing urine more often than usual
  • a feeling that you cannot wait when you need to pass urine
  • needing to wait for the flow of urine to begin
  • having a weak flow of urine
  • feeling that you have not fully emptied your bladder.

It is important to contact the hospital straight away if you cannot pass urine at all. This is a rare side effect caused by swelling that closes the urethra completely. This stops urine flowing out of the bladder. It may affect you after brachytherapy for prostate cancer. You may have drugs that reduce the swelling. Or you may have a tube (catheter) put into the bladder for a short time.

Bowel side effects

Pelvic radiotherapy can cause some of the following side effects:

  • loose stools (poo) or diarrhoea
  • hard stools or constipation
  • needing to empty your bowel (poo) urgently
  • cramping pains in your tummy (abdomen) or back passage (rectum)
  • passing a lot of wind.

Some other, less common side effects are:

  • feeling you need to go to the toilet although your bowel is empty (tenesmus)
  • passing mucus or blood when you empty your bowels
  • bleeding from piles (haemorrhoids)
  • slight soiling of your underwear or some leakage (incontinence).

Bowel side effects usually start to improve about 2 weeks after radiotherapy finishes. Sometimes, they may take a few months to get better. Occasionally, some side effects may be permanent.

Coping with bowel side effects

Tell your radiotherapy team about any bowel side effects you have. They may suggest making some changes to your diet during radiotherapy. Or they may give you drugs to help. Follow their advice carefully. Tell them if your side effects get worse.

Diarrhoea is the most common side effect. It usually starts during radiotherapy or after 2 weeks of treatment. If you have diarrhoea, your radiotherapy team may give you tablets to help reduce it. Try to drink at least 2 to 3 litres (3½ to 5½ pints) of fluids each day.

If you have any soiling or incontinence, tell your radiotherapy team. They will give you advice about coping with incontinence and looking after your skin.

There are some things you can do to help with bowel side effects:

  • Try to limit drinks containing alcohol or caffeine (for example, tea, coffee, drinking chocolate or cola).
  • Avoid foods and drinks that give you wind, such as pickles, beans, curry and fizzy drinks.
  • Do gentle exercise to help with wind. Or try taking charcoal tablets, which you can buy at the chemist. These can affect other medicines, so always ask your doctor or pharmacist first.

We have more information about coping with bowel problems.

Erection and ejaculation problems

Radiotherapy to the pelvis can cause problems with erections and ejaculation. Your doctor or nurse can talk to you about how to manage these.

Problems with erections

Radiotherapy to the pelvic area can cause problems getting or keeping an erection. This is called erectile dysfunction (ED). You may find your erections are not as strong as they were before the treatment. You may get an erection, but then lose it. Or you may be unable to get an erection at all. Your radiotherapy team can explain what is likely to happen.

Although you may feel embarrassed, talk to your doctor if you are having problems. There are treatments for ED that can help. We have more information about ED after cancer treatment.

It is natural to worry about how ED will affect your sex life. It may help to remember there are lots of ways to give and receive pleasure. Sex is not only about penetration. There are other ways to be intimate with your partner, such as oral sex, mutual masturbation or using sex toys. Sometimes both you and your partner may enjoy just hugging and kissing as ways of being intimate.

Changes in ejaculation

You may have a sharp pain when you ejaculate. This is because radiotherapy can irritate the tube that runs through the penis from the bladder (the urethra). The pain should get better a few weeks after treatment finishes.

Pelvic radiotherapy reduces the amount of semen you produce. This means when you ejaculate, you may only notice a small amount of fluid. Or you may not produce any semen at all. This is called a dry ejaculation. But you will still be able to orgasm (climax). You may find the sensation of an orgasm feels different from before.

Effects on the vagina

If your treatment involves the vagina, it may cause changes during and after treatment, such as:

  • skin reactions
  • dryness
  • narrowing.

Vaginal changes can be uncomfortable. They may make having vaginal sex painful. They may also make it difficult if you need to have internal examinations in the future.

Your doctor, radiographers or nurse can give you advice about ways you can prevent or cope with vaginal changes. Try to follow their advice, and ask for more help if you need to. It can be hard to talk about these side effects, but your radiotherapy team can usually help.

Coping with vaginal dryness

The following products may help with dryness:

  • Lubricants – lubricants are a gel or liquid that you use inside the vagina to make it wetter. It can help to use a lubricant before or during vaginal sex or before an internal examination.
  • Vaginal moisturisers – a vaginal moisturiser is a cream you apply regularly to draw moisture into the vaginal walls.
  • Vaginal oestrogen – vaginal oestrogen usually comes as a cream, a small pellet (pessary) or a ring. It releases the hormone oestrogen into the vagina. This may improve dryness if you have had the menopause. Vaginal oestrogen is not suitable for everyone or after some types of cancer.

Your doctor can prescribe these products. You can also buy lubricants and moisturisers from a pharmacy or a supermarket, or online.

We have more information about coping with vaginal dryness

Preventing narrowing of the vagina

Your radiotherapy team may give you vaginal dilators to help stop the vagina from narrowing. Dilators are tampon-shaped plastic tubes of different sizes. You use these regularly inside the vagina with a lubricant, to gently push the walls of the vagina apart.

Your nurse or radiographers will explain if dilators may be helpful, and how to use them.

You may also be able to help stop the vagina narrowing by regularly:

  • having vaginal sex
  • using a dildo or vibrator inside the vagina
  • using lubricant and fingers inside the vagina.

Early menopause

If you have ovaries and have not been through the menopause, pelvic radiotherapy will usually cause an early menopause. This is because this treatment stops the ovaries working. You will not be able to get pregnant anymore, and monthly periods will eventually stop. For a time, you may get menopausal symptoms. These may include:

  • hot flushes and sweats
  • vaginal dryness
  • passing urine more often
  • aches and pains.

You may also have:

  • a lower interest in sex
  • sleep problems
  • mood swings
  • lower self-confidence
  • poor concentration and memory.

An early menopause may also cause a higher risk of some longer-term health problems. These may include:

Coping with menopausal symptoms

Having an early menopause can be difficult to cope with. Sometimes it can be distressing. But there are things that can help.

Ask your doctor or nurse for support, and advice about treatments and managing menopausal symptoms. Or contact our cancer support specialists.

Hormone replacement therapy (HRT)

Hormone replacement therapy (HRT) is treatment to replace the hormones that the ovaries stop producing during the menopause.

HRT is not suitable for everyone. It may increase the risk of some types of cancer coming back. Your cancer doctor or nurse can give you more information.

We have more information about menopausal symptoms and cancer treatment.

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.