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Radiotherapy to the pelvis for anal cancer

This information is about radiotherapy to the pelvis for cancer of the anus. It describes all possible treatments, and some may not apply to you. The doctor, nurse or specialist radiographer will discuss your treatment with you and explain anything you do not understand.

Please share this information with your family and friends. They can have a role in helping you. It’s important that they feel well-informed and understand what is happening.

If you would like more detailed information about your own treatment, please ask the staff. You may have heard about radiotherapy from people you know or from the patients at The Christie. Remember that their information may not apply to you.

When is radiotherapy offered and what are the benefits?

Each patient has their treatment planned individually, and your clinical team at The Christie will discuss with you the type and length of treatment recommended for you. Your clinical team will use the following chart to discuss the reasons for treatment and the benefits of treatment you are being offered.

Why is radiotherapy offered?

For anal cancer

For advanced anal cancer

What is the aim of treatment?

To treat the cancer with the intention of curing the cancer

To control symptoms like pain, bleeding or discharge

Will I need chemotherapy?

Most patients will be offered chemotherapy. Patients need to be generally fit and have good kidney function

In most cases this is offered without chemotherapy, however, your clinical team will discuss this with you

What is the duration of the radiotherapy?

23 to 28 treatments

This can be variable and will be discussed with you by your clinical team

Are there any alternative treatments?

Surgery is only used in specific cases

The alternative would be to control symptoms with medication or other procedures

What happens after radiotherapy?

You will be seen in clinics by your clinical team 6 weeks after completing treatment. Further scans shall be arranged 3 months after the completion of treatment and again at 6 months

Your clinical team will discuss this with you

When is surgery used for anal cancer?

Surgery is only used in specific cases:

  • if the cancer is small, your clinical team will discuss this with you if this is appropriate for you
  • if there is cancer left behind after combination treatment with chemotherapy and radiotherapy
  • if the cancer were to come back locally in the future
  • if you experience incontinence

In these cases, surgery involves removal of the anus. This means that patients would have a permanent stoma or colostomy.

Consent to treatment

We will ask you to sign a consent form agreeing to accept the treatment that you are being offered. The basis of the agreement is that you have had The Christie’s written description of the proposed treatment and that you have been given an opportunity to discuss any concerns.

You are entitled to request a second opinion from another doctor who specialises in treating this cancer. You can ask your own consultant or your GP to refer you.

Your consent may be withdrawn at any time before or during treatment. Should you decide to withdraw your consent, a member of your treating team will discuss the possible consequences with you.

Exposure to radiation during pregnancy can be dangerous for the foetus (baby). The effects can be serious and may result in birth defects, childhood cancers, impaired growth and mental development. For these reasons we would advise against becoming pregnant before or throughout your radiotherapy treatment. If you find out you are pregnant after your radiotherapy has finished and believe your dates overlap with treatment, please contact your consultant’s secretary.

What is radiotherapy?

You can see general information about the treatment on our radiotherapy pages.

Planning for your treatment

The doctor who is in charge of your treatment is a clinical oncologist. You will be cared for by a team including consultants, resident doctors, radiographers and nurses. The team also has specialist radiographers who are dedicated to caring for patients with anal cancer. Your clinical team will examine you and arrange for tests such as X-rays, scans and blood tests as necessary. These are to check your general health, and to help decide on the details of your treatment.

In choosing your treatment, your clinical oncologist at The Christie has carefully considered the nature of your illness and your particular needs with regard to your treatment plan. During your initial radiotherapy planning appointment, the radiographers will be able to tell you exactly when you will start your treatment. As everybody’s treatment varies, the amount of time needed to plan the treatment varies.

You may have between 5 and 28 treatments.

Planning the treatment

To help with the planning of your treatment, you will have a CT scan.

The scans which are undertaken to plan your radiotherapy are solely aimed to give enough information to plan the radiotherapy accurately.

These scans are not diagnostic and therefore do not give enough information to see the status of your cancer or any other abnormalities.

You may be asked to drink a special contrast drink before your scan which highlights the bowel to get clearer pictures and improves the planning of your treatment. You may also be given an injection of contrast. The appointment letter for your scan will include a leaflet explaining in more detail what will happen.

During this planning session the radiographers will draw some marks on your pelvis with a skin pen. These marks do wash off and so some permanent marks, like tiny black freckles, will need to be made. These marks help the radiographers set you up in the correct position for

treatment every day. The radiographers will ask you to lie on your back, but if this is not possible please discuss this with the radiographers.

It is important for you to stay well hydrated. Drink plenty of water the day before and on the morning of your scan.

You should continue this throughout your treatment. Aim for at least 2 litres of fluid each day. This can be water, juice, squash and decaffeinated drinks.

For some patients, large amounts of gas in the bowel can affect the area being treated. We all produce gas throughout the day. Most of it comes from the air we swallow when we are eating and drinking, and some comes from the types of foods we are eating or from what we are drinking. The following information gives you some suggestions on how you can reduce bowel gas before your radiotherapy planning scans and throughout your treatment. It is important to try and empty your rectum of gas or poo before your planning scan and your treatment.

Food and drink to avoid or limit which produce more gas:

  • fizzy drinks (for example, beer or coke)
  • cereals
  • beans and pulses
  • vegetables in the brassica family (such as broccoli, cauliflower, cabbage, sprouts)
  • nuts and seeds
  • caffeinated drinks

Lifestyle tips to reduce excess gas

  • Avoid skipping meals.
  • Avoid chewing gum.
  • Chew food and sip drinks slowly.
  • Take regular exercise to encourage bowel movement.
  • Drink plenty of water.
  • Try things that help your digestion (such as ginger and peppermint tea).

Please follow this dietary advice 2 to 3 days before your planning scans, 2 to 3 days before starting treatment and throughout the duration of your treatment.

If you are able to, we ask that you try to empty your bowels of gas and/or poo before your planning scan and treatment.

What happens during treatment?

On the day of your first treatment, you will come to the radiotherapy department. If you are an inpatient, a porter or clinical support worker may collect you from your ward and escort you to the department. On the treatment unit you will meet a clinical support worker. They help patients plan their appointments for the treatment. The radiographers will have the details of your treatment which the doctor has carefully planned . They will discuss the treatment with you and how to minimise any side effects. They will also check whether you are still happy to go ahead with your treatment. This is the ideal opportunity to ask any questions you may still have.

You will be asked to drink a set amount of water an hour before having treatment each day. The radiographers will take you into the treatment room and ask you to loosen your clothing around your pelvis so that they can see the marks made during treatment planning. They will help you onto the treatment bed.

The radiographers will then adjust the bed and your position so that you are in the correct position for the treatment. They will try to make you as comfortable as possible as you will be asked to keep still for the duration of the treatment.

The radiotherapy machines are quite big and if you have never seen one before you might feel anxious. There is no need to worry, the treatment is painless.

Each session may take about 15 minutes but the actual treatment only lasts a few minutes. The radiographers operate the machines from outside the room. When all the adjustments have been made and you are in exactly the right position, the radiographers will make sure you are comfortable and then leave the room to switch the machine on. There is nothing to feel and nothing to see. The machines make a buzzing noise when they are giving treatment.

During your treatment the radiographers will need to take images or a scan of the area you are having treated. This will be done at the same time as your treatment and you probably will not notice that the images or a scan have been taken. These images are purely to check that you are in the correct position and not to check how the cancer is responding to treatment.

Cameras inside the room give the radiographers at the control desk a clear view of you and they will be watching you at all times. If there is an emergency, wave your hand and the radiographers will come in to check on you. If you feel the need to cough or sneeze, just do so into open air. So long as you do not move your arms you will settle back into the same position you were in originally.

Once your treatment has finished, they will help you off the bed and arrange your next visit. You are then able to return home or to your ward.

It is very important that you do not miss treatment days as this may make your treatment less effective. If you feel you are unable to attend for any reason, please telephone the staff on your treatment machine and discuss the problem with a radiographer. Call the radiotherapy department on 0161 446 3485.

Some questions you may have

Radiation used in medical treatment is given in controlled, carefully measured doses. The aim is to include all tissues that could possibly contain cancer cells while minimising the dose to the normal tissue.

No. Patients treated by X-rays do not become radioactive. The radiation does not stay in your body after treatment, so you cannot do anyone else any harm. It is safe for you to mix with other people including children and pregnant women.

Not usually. The treatment may make you feel more tired than normal. Please tell your treatment team about any existing medical conditions and continue with any medication you may be taking. Ask your Christie doctor if you are worried about any other health problems.

If you are having treatment as an outpatient the radiographers will give you appointment times for your first 5 treatments when you attend for your planning session.

After that you can arrange with your treating team the time that suits you, wherever possible. Please try and be flexible and give priority to your treatment sessions over general appointments. The time you prefer may not be available at the start of your treatment because of the large number of patients on the treatment unit. If you need a specific time, please give the treating team as much notice as possible, although the department cannot guarantee to meet all requests. The time we give you may vary half an hour either way each day due to emergencies. Please check your appointment time for the following day before you leave, in case of any changes.

You will speak with your clinical team once a week to check that you are managing with the treatment and give you advice or medications to help. This may be a telephone call or in person. You do not need an appointment, but if you are worried about anything then please speak to the radiographers. If you are an inpatient, you will be seen on the ward by one of the treating team.

You will usually have your treatment as an outpatient. Some people continue to work during part of their treatment.

However, after daily travel and treatment, you may feel tired and need to rest. Your treating team will have discussed with you about travelling for your treatment as an  outpatient. However, if you do become unwell during your treatment we may admit you as an inpatient to support you through your radiotherapy, though this is rare. You will not have to stay in bed, so bring suitable day wear, so that you can get dressed if you feel well enough.

Many patients are able to bring themselves or can ask a friend or relative to help them out. If you think you may need ambulance transport, please discuss this with a radiotherapy support worker or radiographer on or before your first visit to the radiotherapy department. Ambulance transport can be arranged subject to eligibility criteria based on medical need. There also needs to be a medical reason for you to bring an escort on hospital transport.

There can be delays for some time either side of your appointment because of the high demand for transport. Please take this into account when you are deciding whether to use ambulance transport or not.

Hospital transport is provided by a variety of ambulance services depending on patients’ location. If you are attending The Christie at Withington, please contact the transport liaison office at The Christie directly on 0161 446 8114/8143 for advice and bookings. If you are attending The Christie at Macclesfield contact 0161 956 1719.

Questions you may want to ask your doctor

  • What type and extent (stage) of disease do I have?
  • Why are you recommending radiotherapy for me?
  • What might be the benefits and side effects?
  • Is there any alternative treatment, and, if not, why is this?
  • What will the radiotherapy involve and how many times will I have to visit the hospital?
  • Will there be any lasting effects from treatment?

Chemotherapy as well as radiotherapy

Some people who are having a course of radiotherapy will also have chemotherapy. If needed, chemotherapy will be given as an outpatient unless your clinical team feels it necessary to admit you. Your treating team will give you further information about the potential side effects of chemotherapy treatment.

What happens after radiotherapy?

You will receive a telephone follow-up around 2 weeks after completion of treatment.

You will also be reviewed in clinic by your clinical team about 6 to 8 weeks after the end of your treatment. Further scans shall be arranged at 3 months and 6 months after the end of treatment. You will have regular follow-up appointments.

If you need any help or advice, please contact the clinical nurse specialists on 0161 918 7002. Arrangements can be made for a district nurse to visit you.

Side effects

Side effects happen because as well as destroying cancer cells, radiotherapy can also damage healthy cells nearby. When planning treatment, the clinical team choose the dose that will give the best chance of destroying the cancer cells and reducing the symptoms – with the smallest possible effect on healthy tissue. Some patients are more sensitive to radiation than others, and are more likely to experience side effects. We do not know which patients are before treatment starts. For some patients the cancer itself can cause damage to the surrounding tissue and structures.

There are short-term (acute) and long-term (late) side effects with the treatments. You can discuss any issues with your team in the radiotherapy department.

Short-term (acute) side effects

These will generally develop after 7 to 14 days, and last up to 12 weeks after the treatment ends. They are usually

temporary and may vary in severity from person to person. Some patients may develop minimal side effects and others may have more. If you have any questions about side effects, please ask any member of the team treating you.

Here are some acute common side effects experienced and what you can do to help.

  • Diarrhoea is a common symptom. If this occurs, a low fibre diet may help reduce symptoms. Medication may also be helpful.
  • Symptoms similar to cystitis such as increased frequency and burning or difficulty when passing urine. We recommend that you take plenty of fluids, aim for 2 litres per day, but avoid drinking alcohol or lots of tea and coffee.
  • Tiredness varies greatly from person to person. Continuing with gentle exercise can help, but rest when you feel tired.
  • You may feel sick with treatment, and this is more common if you are having chemotherapy. Anti-sickness tablets may be beneficial. Please discuss this with your treating team.
  • It is common for the skin on your pelvis to become dry, red, itchy and may break down in certain areas . This usually becomes very sore and painful and painkillers are likely to be required. We may supply you with an appropriate cream to help keep the skin moisturised . If your skin does break down you may be given other creams and dressings to use. Please discuss this with your treating team.
  • Pain is a common symptom. If this occurs, medication may be helpful.

Bowel

Your bowels may become disturbed due to your treatment. For most patients, this is in the form of diarrhoea but occasionally it can be constipation. Diarrhoea can start after about 2 weeks of treatment and last for several weeks after treatment ends. With diarrhoea, patients often get increased ‘wind’, severe urgency, occasional tummy (abdominal) gripes/cramps, tummy (abdominal) bloating and may pass mucus from their bottom.

Occasionally patients may have incontinence or accidents. If this happens, please talk with your treating team as changes in lifestyle and medication may be beneficial.

What you can do to help

It is important that you continue to eat nourishing food during and after treatment. Ask the nursing or radiotherapy staff for a copy of ‘Eating – Help Yourself’ which is dietary information about coping with eating problems such as loss of appetite or weight loss.

If you have diabetes you can ask for a copy of ‘Eating well with diabetes’. While you have diarrhoea, you may find that your symptoms are eased by following a lower fibre diet: see The Christie booklet ‘Eating well when following a low fibre diet’.

If your poo or stools become loose and more frequent, try to reduce fibre in your diet. Fibre is the part of food that passes through your gut undigested. It is in whole grains, pulses, vegetables and fruit. To reduce fibre, we suggest you:

  • replace wholemeal, multi-grained or seeded bread with white bread
  • replace wholewheat cereals, oat based cereals, porridge and muesli with Rice Krispies, cornflakes or Special K
  • replace wholemeal biscuits with biscuits made from white flour such as rich tea, Marie biscuits, shortbread or custard creams
  • avoid nuts and pulses (baked beans, kidney beans, peas and lentils)
  • eat only small amounts of fruit and vegetables and avoid eating their skins, pips and seeds

While following a lower fibre diet, you will need to take a complete multi vitamin and mineral supplement daily until you return to your full diet. These are available from your local chemist or supermarket. It is important to drink enough to replace fluid that is being lost. Aim for 2 litres of fluid per day to prevent dehydration. Fluids can include milk, milkshakes, soup, fruit juice, squash, fruit tea, herbal tea as well as tea, coffee and water. At this time you may find it easier to eat little and often throughout the day eating small amounts but at frequent intervals.

If you have reduced some of the fibre rich foods in your diet and are still having symptoms you may need additional medication such as loperamide, codeine phosphate or fybogel which can be prescribed for you by the clinical team.

The bowel symptoms vary greatly between patients. Most people start to see some improvement 2 to 3 weeks after treatment has finished. Some patients are virtually back to normal within 6 weeks, for others they remain unsettled for several months and for some they may never return to what was normal for them.

When you have no more diarrhoea, slowly start re-introducing the foods that you have been avoiding. By adding in one new fibre-containing food each day, you will find the foods your body can tolerate without the symptoms returning.

Keep reintroducing new foods one at a time until you have returned to your normal diet. If you are diabetic and develop diarrhoea, follow the above recommendations. Make sure you include lower fibre starchy foods such as white bread, white rice, cornflakes, Rice Krispies, yoghurt and milk, at each mealtime and snack. Return to your normal diet once symptoms have resolved.

Bladder

In less than 1 in 2 patients, radiotherapy can irritate the bladder and give symptoms similar to cystitis such as increased frequency and burning or difficulty when passing urine. We recommend that you drink plenty of fluids, aim for 2 litres of fluid per day.

It is best to avoid drinking lots of tea and coffee and reduce alcohol. Some patients are virtually back to normal within 6 weeks, for others they remain unsettled for several months and for some they may never return to what was normal for them.

Tiredness

You will feel tired during treatment so rest is important, although a small amount of gentle exercise each day has been found to be beneficial in reducing fatigue. This is explained further in The Christie booklet ‘Be active, stay active: A guide for patients and their carers’ which is available from the cancer information centre.

Tiredness often continues to affect people after treatment ends, so you may need help with housework and shopping. Radiotherapy can be a demanding treatment. If you are feeling low or are not coping, let the nurses, doctors or radiographers treating you know so they can discuss with you what might help.

Nausea

Very occasionally you may feel sick during your radiotherapy treatments, your taste changes or you go off your food. This is more likely to happen if you are having chemotherapy. Let your treating team know because they can suggest things that may help.

Skin/pubic hair

Skin soreness is expected, during and after your treatment. It can also be itchy and it might peel, blister and cause pain. You should moisturise the intact skin in your pelvis every day from the start of your radiotherapy treatment. We may provide a moisturiser, but you can use any of your normal moisturisers. Avoid products with sodium lauryl sulphate (SLS), as this ingredient may irritate your skin. You will be given different creams, moisturisers, dressings and painkillers to help.

Please speak with your team if you are struggling with this side effect. Most people start to see an improvement 2 to 3 weeks after treatment has finished.

Some patients do find that their pubic hair falls out during or shortly after treatment. This usually grows back but it may be thinner.

Pain

Pain is a common symptom during treatment. You may require medication to help. Most people start to see an improvement 2 to 3 weeks after treatment has finished.

Sex and contraception

It is important for patients to take contraceptive precautions while having radiotherapy. A course of radiotherapy is the equivalent of a major operation; it may be some months before you feel interested in the physical aspect of your relationship. If this is a concern to you, please let your treating team know so they can discuss with you what might help.

There are some long-term side effects that may or not happen in the months or years after treatment. They can vary in severity. Your team will discuss with you before starting treatment. They may be managed with lifestyle advice and medication.

Bowel

Scarring may result in feeling the urge to go for a poo more often or you may feel you have less control (incontinence). Some people may need to wear pads. Your GP or treating team can refer you to the local incontinence team to provide these pads. You may be referred to a specialist if your symptoms continue. Some people may have bleeding from the back passage. If this occurs please inform your team.

There is a small risk that you may need surgery to the bowel due to scarring from the radiotherapy.

If you have significant rectal bleeding, you must contact your surgical team. Rarely, radiotherapy may inflame the healthy bowel, affecting how well it works. This may need alternative nutrition or surgery to manage. Very rarely, a blockage, or narrowing of the bowel or hole may occur, even at an early stage. This could require surgery, although the possibility is low.

Bladder

Scarring may result in feeling the urge to go to the toilet for a wee more often or you may feel you have less control.

Some people may need to wear pads. Your GP or treating team can refer you to the local incontinence team to provide these pads. There is a small risk that you may need surgery to the bladder due to the scarring from the radiotherapy.

Fatigue (tiredness)

Some people find that tiredness continues for several months after their radiotherapy treatment has finished. Planning ahead can help with tiredness. If you are finding that you are still struggling with tiredness please see the Macmillan booklet ‘Living with fatigue’.

Skin/pubic hair

As your skin heals, long-term skin changes in the pelvic area can happen because of your radiotherapy treatment. You may find that your skin feels itchy, dry or tighter due to your radiotherapy. This is usually well managed with a moisturiser.

Your skin can change in colour and have threadlike veins in the pelvic area. The skin in the pelvic area will be more sensitive to the sun. We recommend that you keep the area covered or use a sunblock.

Your pubic hair may grow back thinner or may not grow back at all in some areas. If this is a concern to you please speak with your GP who may be able to refer you to a specialist for support.

Bone changes

Radiotherapy can cause bone changes (bone weakening) in the treatment area. In the pelvis this means the hip bones, tail bone (sacrum) and top of the legs (femurs). This is an uncommon side effect, but if you are having any problems, speak to your GP or your treating team.

The bone changes can cause pain which may be described as dull, constant and achy. It may cause trouble moving and walking.

If you have dull aching pain in the pelvic bones that lasts more than a few weeks, it should be investigated. On scans small hairline fractures may be seen, but this is rare.

Fertility and sexual function

Radiotherapy can cause long term changes to your sexual function. Your clinical team may suggest you avoid having anal sex during and after radiotherapy. If you have bowel problems or a sensitive anus after radiotherapy you may want to wait until symptoms have settled before trying anal sex again. If this is a concern for you and your partner, please let your clinical team know so that this can be discussed further with you.

Female late effects

This treatment causes infertility which is permanent and very likely to induce the menopause during the 3 to 4 months after treatment in patients who are still having regular periods. Your team may advise you to start hormone replacement therapy (HRT) if your symptoms are troublesome.

If infertility is an issue for you and your partner, please let your team know before any treatment is planned. If appropriate they can arrange for you to see a fertility specialist.

Radiotherapy can cause vaginal narrowing and dryness which can affect your sex life or gynaecological examinations in the future. However, advice will be given about lessening this problem.

Male late effects

This treatment can cause infertility which is permanent. If this is a concern please discuss this with your treating team.

Some patients may notice it is more difficult to achieve and maintain an erection following a course of radiotherapy. This is more common in men over the age of 50 and may be permanent. Some men may also have ejaculation changes. Treatment is available to help in the form of medication from your GP. If this does not suit you, you can be referred to a specialist erectile dysfunction clinic.

Secondary cancer

This treatment has a small risk of a secondary cancer. This means that the radiotherapy treatment given for this cancer could cause another cancer in the future. This is usually a different cancer in the pelvis which occurs many years after the radiotherapy treatment. If this is a concern for you, please discuss this with your clinical team.

Delayed wound healing

This treatment has a small risk of delayed wound healing, so it may take you longer to heal after surgery if this is needed in the future. If this is a concern for you please discuss this with your clinical team.

Last updated: January 2026