Pelvic radiotherapy side effects

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:

• the area of the pelvis having treatment
• whether you have external or internal radiotherapy
• how much radiotherapy you are having
• other cancer treatments you are having, such as  surgery, chemotherapy or hormonal therapy.

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.

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.

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.

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.

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.

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.

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.

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. 

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.