Side effects during treatment

How pelvic radiotherapy affects you will depend on the type of cancer you have, the dose of radiotherapy given and if you’re having external or internal radiotherapy. Your cancer doctor, specialist nurse or radiographer will explain the most likely side effects in your situation.

Some possible side effects are:

  • tiredness (fatigue)
  • effects on the skin in the area being treated
  • changes passing urine
  • bowel changes.

Many side effects can be managed successfully and most will begin to get better a few weeks after treatment ends. Tell your cancer doctor, specialist nurse or radiographer about any new symptoms or if you are having difficulties with symptoms.


Radiotherapy often makes you feel tired, especially towards the end of the course of treatment. The tiredness (fatigue) continues after the treatment has finished and may last for a few months. You’ll find that your energy levels will gradually improve. However, it can take a while to recover, so don’t be too hard on yourself.

There are some things you can do to help manage tiredness:

  • Pace yourself so you don’t overdo it and take regular rests.
  • If you’re able to, plan some physical activity into your day, such as a short walk. This will help to build up your energy levels.
  • Ask family and friends to help out, perhaps with things like household tasks and taking care of children.
  • Make sure you get enough sleep.

Effects on the skin

Sometimes, radiotherapy can cause a skin reaction in the area being treated. The skin may redden or get darker and become dry, flaky and itchy. Towards the end of treatment, the skin sometimes becomes moist and sore. There may be breaks in the skin, especially around the back passage (anus) and groin.

Your radiographer or nurse will check your skin regularly. Tell them if your skin is sore or if you notice any other changes. They will assess your skin and may prescribe a cream or dressings to help. They can also prescribe painkillers, if needed.

Skin reactions may be at their worst up to two weeks after radiotherapy finishes, before beginning to improve. If you’re sore or have any problems with your skin during this time, contact the radiotherapy department for advice.

Pelvic radiotherapy may make the hair around your genital area (pubic hair) fall out. It should start to grow back again within a few weeks after radiotherapy finishes, but it may be thinner. Occasionally, hair loss can be permanent.

Skin care

Your radiographer or specialist nurse will tell you how to look after the skin in the treated area. They will usually give you the following advice:

  • Keep the skin in the area clean. Wash it gently and carefully pat it dry with a clean, soft towel.
  • Check with the radiographer or nurse before you put anything on the skin in the treated area.
  • It is better to have a shower than take a bath, as soaking in a bath can make the skin too moist. When having a shower, use a very gentle stream of lukewarm water. If you have a bath, don’t soak in the water for longer than a minute or two.
  • Use a simple moisturiser on the skin. Your radiographer or specialist nurse will be able to suggest moisturisers you can try.
  • Wear loose underwear made from natural fibres, such as cotton or silk, that won’t rub against the skin. Avoid wearing tights or tight-fitting trousers.
  • If you shave, wax or use hair removal creams, wait until a few weeks after radiotherapy is over and any skin reaction has healed.
  • Protect the skin in the treatment area from the sun for the first year after radiotherapy. Even after any skin reaction has settled, you should always wear sunscreen with a high sun protection factor (SPF) of at least 30.
  • Wash your underclothes, bed linen and towels using a non-biological powder or liquid for people with a sensitive skin.
  • Avoid smoking, as this can make skin reactions worse.

Bladder side effects

Pelvic radiotherapy can cause irritation and inflammation of the lining of the bladder. You may find that you have some of the following symptoms:

  • a need to pass urine often (frequency)
  • a need to pass urine during the night (nocturia)
  • a burning sensation when you pass urine (similar to cystitis)
  • a feeling that you can’t wait when you need to empty your bladder (urgency)
  • blood in your urine (haematuria)
  • leaking small amounts of urine (incontinence).

Your doctor may prescribe painkillers or anti-inflammatory drugs to ease these symptoms. Sometimes drugs called anticholinergics are also used. Your doctor or specialist nurse can give you more information.

What you can do

  • Drink at least 2–3 litres (3.5–5.5 pints) of fluids a day. Concentrated urine can irritate the bladder and make symptoms worse. Drinking more reduces this.
  • Avoid drinks that might irritate the bladder. These include drinks containing caffeine (tea, coffee, drinking chocolate, cola), alcohol, fizzy drinks, acidic drinks (orange and grapefruit juice) and drinks with artificial sweeteners (‘diet’ or ‘light’ drinks).
  • Cranberry juice or capsules may help reduce symptoms.
  • Avoid smoking, which can make the symptoms of bladder irritation worse .
  • Let your nurse or radiographer know if you have any incontinence.

If symptoms get worse, you have a high temperature, or you feel you can’t pass urine, contact the hospital straight away.

If you have incontinence, your nurse will take a urine sample to check for signs of infection. This is a common and easily treatable cause of incontinence. They may also arrange for you to have pads if needed and give you advice on looking after your skin. If the problem doesn’t settle within a few weeks, the nurse can refer you to a continence specialist for advice and treatment.

Sometimes further tests will be done to assess the incontinence. Your specialist team will discuss these with you if you need them.

It is usually possible to improve incontinence. So it is important to let your doctor or nurse know if it is a problem for you.

You can get a card to show to staff in shops and other public places if you need to use their toilet urgently.

Possible urinary problems after treatment for prostate cancer

As well as bladder irritation, radiotherapy for prostate cancer may cause irritation of the tube that carries urine from the bladder to outside the body (the urethra) and swelling of the prostate gland. In addition to symptoms such as urinary frequency and urgency, this can cause you to:

  • need to wait for the flow of urine to begin (hesitancy)
  • have a weak flow of urine
  • feel that you haven’t quite emptied your bladder.

Your doctor may prescribe anti-inflammatory drugs, steroids or alpha-blockers, which can help reduce these effects. Alpha-blockers such as tamsulosin (Flomax®), terazosin (Hytrin®) and doxazosin (Cardura®) are tablets that work by relaxing the muscle in the bladder and prostate gland so that you can pass urine more effectively.

During or after radiotherapy for prostate cancer, some men develop a sudden inability to pass urine. This is called acute urinary retention. It’s rare in men having external radiotherapy. But it sometimes occurs after brachytherapy, particularly in men who had urinary symptoms before treatment and have a larger prostate gland.

Acute urinary retention is caused by the prostate gland swelling and blocking the urethra. It may be treated with drugs that reduce swelling, such as steroids or anti-inflammatory drugs (NSAIDs), or by putting a tube (catheter) into the bladder for a short time. If you are unable to pass urine it is important to contact your specialist team as soon as possible. If you can’t contact them, you should go to your nearest A&E department.

Bowel side effects

Pelvic radiotherapy can cause some of the following side effects:

  • loose stools, diarrhoea or sometimes constipation
  • a need to open your bowels urgently
  • cramping pains in your tummy (abdomen) or back passage
  • passing a lot of wind.

Some other, less common side effects are:

  • feeling as if you need to go to the toilet although your bowel is empty (tenesmus)
  • passing mucus or blood when you empty your bowels
  • slight soiling of your underwear or some leakage (incontinence), although this is rare.

Tell your cancer specialist, specialist nurse or radiographer about any bowel side effects you have.

Diarrhoea is the most common side effect and usually starts during or after the second week of radiotherapy. If you have diarrhoea, your specialist will prescribe anti-diarrhoea tablets to help reduce it.

Some people are advised to make changes to their diet during radiotherapy. This may involve eating a bland diet and cutting down on fibre. Your specialist nurse or radiographer will tell you if this is appropriate for you. If you have diarrhoea, you should drink plenty of fluids.

If you have tummy cramps, tell your cancer specialist or nurse. They can prescribe drugs to help with this. If you’re constipated, your doctor will usually prescribe a laxative and give you advice on diet.

Let your nurse or radiographer know if you have any soiling or leakage. They will give you advice on coping with this and looking after the skin in the area.

Bowel side effects usually start to improve about two weeks after radiotherapy has finished. Sometimes, it may take a few months for the bowel to settle down.

What you can do

  • Drink at least 2–3 litres a day (to replace fluid lost through diarrhoea) and avoid caffeine and alcohol.
  • Follow any dietary advice given by the hospital.
  • Take your anti-diarrhoea tablets or other medicines you have been prescribed.
  • Avoid foods and drinks that give you wind, such as pickles, beans, curry and fizzy drinks.
  • Gentle exercise may help if you have a lot of wind. Or you could try charcoal tablets, which you can buy at the chemist.
  • If side effects don’t get better, tell your specialist nurse or doctor.
  • Avoid smoking, which stimulates the bowel and can make diarrhoea worse.

There is more information about coping with bowel problems in our section on eating problems and cancer.

Toilet card

If you need to go to the toilet more often, or feel that you can’t wait when you do want to go, you can get a card to show to staff in shops, pubs and other places. The card allows you to use their toilets without them asking awkward and embarrassing questions.

Macmillan produces this toilet card. We hope this card helps you get urgent access to a toilet, but we cannot guarantee that it will work everywhere.

Sex life and fertility

Pelvic radiotherapy will affect your fertility (ability to get pregnant or father a child). It can also have effects on your sex life.

Pelvic radiotherapy will bring on the menopause in women who are still having periods.

Back to Pelvic radiotherapy explained

About pelvic radiotherapy

Pelvic radiotherapy can be used to treat cancers of the bladder, rectum, anus, prostate, vulva, vagina, womb or cervix.

Follow up

If side effects don’t go away, or you develop any new symptoms after treatment is over tell your cancer doctor.