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. There are also DVDs on radiotherapy which you can take home to watch. Please ask your doctor, nurse or radiographer. 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 doctor at The Christie will discuss with you the type and length of treatment that is recommended for you. The doctor will use the following chart to discuss the reasons for treatment and the benefits of treatment you are being offered.

Questions about radiotherapy for anal cancer

Radiotherapy for anal cancer

Radiotherapy 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 doctor will discuss this with you

What is the duration of the radiotherapy?

28 to 30 treatments

This can be variable and will be discussed with you by your doctor

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 oncologist 6 weeks after completing treatment. Further scans shall be arranged 3 months after the completion of treatment and again at 6 months

Your doctor 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 doctor 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.

Radiation can be harmful to the unborn child. It is important to let the radiographers know if you have missed a period or suspect that you might be pregnant before you are exposed to any radiation.

When will radiotherapy begin?

The doctor who oversees your treatment is a clinical oncologist. They will examine you and may arrange for tests such as X-rays, scans and blood tests. These are to check your general health, and to help decide on the details of your treatment.

You will be cared for by a team including consultants, registrars, radiographers and nurses. The team also has a specialist radiographer who is dedicated to caring for patients with anal cancer.

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 one and 30 treatments.

Planning the treatment

Treatment preparation will be done on a special CT scanner called a an RTP (radiotherapy planning scanner). These machines provide the doctors with images on which your treatment is planned.

You may be asked to drink a special contrast drink before your scan which helps 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 your planning session, the radiographers will draw some marks on your chest with a skin pen. These marks do wash off and so some permanent marks, like tiny black freckles, will need to be made. These will 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.

What happens during treatment?

On the day of your first treatment, you will come to the radiotherapy department. If you are an inpatient, a radiotherapy care assistant may collect you from your ward and escort you to the department.

On the treatment unit, you will meet a radiotherapy 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 explain to you exactly what will happen.

The Christie is a training centre, so you may meet students in the radiotherapy department who may be involved in the delivery of your treatment. If you have any objections, let the radiographers know.

The radiographers will discuss the treatment and how to minimise 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 have.

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 on to 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 large and you may find them a little frightening to begin with, but there is no need to worry – the treatment is painless. Although the machines may come quite close to you, they will not actually touch you.

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 all right 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 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 have been taken. Some machines can complete a scan of the treatment area. These images are purely to check that you are in the correct position and not to check how the tumour is responding to treatment.

Please do not feel abandoned. A closed-circuit television on the control desk gives the radiographers a clear view of you and they will be watching you all the time. If you feel you need to cough or sneeze, the radiographers will tell you beforehand how to let them know this. They will switch off the machine and come in immediately.

Once your treatment has finished, the radiographers 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 to discuss the problem with a radiographer.

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 and to have visitors if you are on the wards.

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 an appointment time for the first treatment when you attend for your planning session. After that, you can arrange with your treating team the time that suits you and the machine.

Please try and be as flexible as possible and give priority to your treatment sessions over other general appointments. The time you prefer may not be available at the start of your treatment because of the large numbers of patients on the unit.

If you need a specific time, please give the radiographers at least 48 hours’ notice. The time we give you may vary half an hour either way each day due to emergencies. You may be given your appointment times for the whole of your treatment on your first visit or alternatively appointment times will be given on each visit for the following day.

Once a week, you will meet your consultant or one of their team. You do not need an appointment for this. We will take you to the clinic before or after your radiotherapy. We will give you a morning or afternoon appointment to fit in with your consultant’s clinic.

If you are an inpatient, the treating team will send a care assistant for you when they have a free slot. If you are going away for the weekend, please let the staff know and they will do their best to treat you before lunch.

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 doctor will have discussed with you the need for travelling daily for your treatment as an outpatient. However, if you become unwell during your treatment, we will usually admit you as an inpatient to support you through your radiotherapy.

You will not have to stay in bed so bring suitable day wear such as tops and skirts or trousers. Treatment usually takes up only a small part of the day and, if you are well enough, you may be able to go out – check with the ward staff first.

Many patients can 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 your first visit to the radiotherapy department.

Transport can be arranged subject to eligibility criteria based on medical need. There also needs to be a medical need 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 transport or not.

Hospital transport is provided by North West Ambulance Service and West Midlands Ambulance Service. Contact the transport liaison office at The Christie directly on 0161 446 8114 or 8143 for advice and bookings. Patients attending The Christie at Salford can contact 0161 918 7800 and patients attending The Christie at Oldham can contact 0161 918 7700 for advice about transport.

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. You will be given outpatient chemotherapy unless your doctor feels it is 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 2 weeks after completion of treatment. You will also be reviewed in clinic by your oncology team about 6 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 in the future.

If you need any help or advice, please contact the clinical nurse specialists on 0161 918 7002 or 0161 446 8407 or the specialist radiographer on 0161 446 8169. Arrangements can be made for a district nurse to visit you.

Side effects

There are short-term (acute) and long-term (late) side effects with the treatments. These are discussed below. It is common to experience most of the side effects, listed below, to some extent.

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, 2 to 3 litres per day but avoid drinking lots of tea and coffee.
  • Tiredness varies greatly from person to person. Gentle exercise and rest when feeling tired may be beneficial.
  • 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 will supply you with an appropriate moisturiser 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.

The side effects happen because, as well as destroying cancer cells, radiotherapy can also damage healthy cells nearby. When planning treatment, the doctors 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.

It seems that some patients are more sensitive to radiation than others, and are more likely to experience side effects. At present, it is not possible to identify these patients before treatment starts. Also, in some patients the cancer itself can cause damage to the surrounding tissue and structures.

Acute side effects will generally develop during the second half of the course of treatment usually 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.


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, intermittent abdominal gripes/cramps, abdominal bloating and may pass mucus.

Occasionally patients may experience incontinence. If this occurs, please discuss this 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 has information about coping with problems such as loss of appetite.

If diarrhoea becomes a persistent problem, please inform your treating team as you may need to follow a low fibre diet to ease your symptoms. If this is the case, follow the diet for as long as your side effects last, then gradually resume your normal diet by adding one new food each day that contains fibre, then if diarrhoea returns you should be able to work out which food has caused it and eliminate this from the diet for a further few weeks.

If you have diabetes and you have developed diarrhoea, you can still follow the low-fibre diet advice but make sure you eat meals and snacks containing low fibre starchy foods such as white bread, white rice and cereals etc from the ‘Allowed list’ below. Once your symptoms have resolved, go back to your normal diabetic diet.

Fibre is the part of grains (flours and cereals), pulses, vegetables and fruit which is not digested and passes down the gut. To cut down the amount of fibre in your diet, try to follow the Allowed list’ food guide below.

If you are following this diet for more than a week, a complete multivitamin and mineral supplement is recommended daily. For a more detailed list please ask for a copy of the low-fibre diet booklet from your radiographer or at the cancer information centre.

If you have followed a low-fibre diet and are still having problems with diarrhoea, you may need additional medication such as loperamide (Imodium®), codeine phosphate or Fybogel which can be prescribed for you.

Please only make the following changes to your diet if you experience loose stools.

Foods to avoid

Allowed foods

Beans, lentils, pulses, Quorn

Meat, fish (tinned, fresh, frozen), eggs, tofu

Wholemeal or granary bread, high-fibre white bread, brown chapatti

White bread, bread sticks, rusks, cream crackers, crumpets, plain scones, plain rolls, white chapatti

Brown rice, whole-wheat pasta and whole-wheat noodles

White rice, pasta, spaghetti and noodles

Biscuits and cakes made with wholemeal flour, or dried fruit e g. flapjack, dried fruit biscuits, mince pies, fruitcake, digestive, plain or chocolate-covered oat biscuits

Biscuits or cakes made with white flour such as Rich Tea, custard creams, shortbread, chocolate coated plain biscuits, plain or cheese scone, doughnuts

High-fibre breakfast cereals for example Weetabix, Shredded wheat, muesli, Fruit and Fibre, bran and oat cereals

Rice Krispies, Cornflakes, Special K, Coco pops, Frosties or similar

All vegetables except those listed in ‘Allowed’ section, vegetable skins, potato skins, sweetcorn

Potatoes, up to 2 tablespoons per day of skinless courgette and cucumber, marrow, carrot, swede, turnip, passata, vegetable juice

Soups – lentil, vegetable

Soups – ‘cream of‘ tomato, chicken, mushroom or oxtail

Fruit, fruit skins except those listed in ‘Allowed’ section, dried fruit

Small portions of melon, seedless grapes (no skins) tinned peaches, pears, mandarin oranges, fruit cocktail

Fruit juice: prune, tomato and juices ‘with bits’

Orange, apple, grapefruit, pineapple and grape juice with no bits

Build up drinks, smoothies, fruit yoghurt with added fruit/cereal  (check label)

Milk, cheese, cheese spreads . All other yogurt, fromage frais, ice cream, jelly, sorbet, ice-lollies, instant whips, crème caramel, milk puddings, custard and blancmange

Wholemeal savoury snacks, nuts, popcorn


Marmalade or jam with peel or pips

Shredless marmalade, jelly jam, honey and lemon curd . Tomato sauce, yeast extract,  2 teaspoons of pickles and chutney

Fruit and nut chocolate, coconut

Plain or milk chocolate, boiled sweets, toffee, fudges, wine gums

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.


In a small number of cases, 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 preferably 2 to 3 litres a day.

It is best to avoid drinking lots of tea and coffee and avoid all alcohol. Some people find a glass of cranberry juice a day helpful. You should not drink cranberry juice if you are taking anti-coagulants. 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.


You may feel tired during treatment so rest is important, although a small amount of exercise each day has been found to be beneficial in reducing fatigue. This is explained further in the DVD/booklet ‘Be Active, Stay Active: a guide to exercising during and after cancer treatment’ which is available from the information centre.

Tiredness often affects people after treatment ends, so you may need help with housework and shopping. Please ask any member of the team treating you if you would like to see a social worker who can advise on help available.

Radiotherapy treatment 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.


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

Some radiotherapy treatments to the pelvis may cause sore skin. This is dependent on the location of your cancer and length of your treatment. We will advise you at the start of treatment if your treatment is likely to do so, and what you can do to help yourself.

Your skin may become red, painful and break down. You will be given different creams, moisturisers, dressings and pain killers 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. The leaflet ‘Skin care during and after your radiotherapy to the perineal area’ has useful advice and is available from your treating team. 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 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.

Sexual relations

It is important for men and women to take contraceptive precautions whilst having radiotherapy. However, 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. However, 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 late side effects of radiotherapy that your doctor will discuss with you. These may occur months or years after your treatment and happen only in a very few cases.

For anyone having radiotherapy for anal cancer, there is a small risk of developing these long-term effects. The risk is higher for people having radiotherapy over several weeks. These late effects may be managed with life-style advice and medication.


Scarring may result in feeling the urge to go more often or you may feel you have less control (incontinence). Some people may need to wear pads. You may be referred to a specialist if your symptoms continue despite lifestyle changes and medication.

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.


Scarring may result in feeling the urge to go more often or you may feel you have less control. Some people may need to wear pads. There is a small risk that you may need surgery to the bladder due to the scarring from the radiotherapy.

Skin/pubic hair

Your skin may change in colour in the pelvic area. It may also be drier, with some areas of scarring. Using a moisturiser long term as part of your daily routine may be beneficial.

The skin in the pelvic area will be more sensitive to the sun. We recommend that you keep that area protected from direct sunlight or use a sunblock.

Your pubic hair may have fallen out during treatment. This usually grows back but it may be thinner. If this is a concern, please inform your team.

Bone changes

A very rare late side effect of radiotherapy to the pelvic area is damage to the bones in the pelvic area. Fine, hairline cracks may occur, known as pelvic insufficiency fractures. If this happens, it can cause pain and may make it difficult to walk and move around. The pain normally goes away overnight and does not stop you from sleeping well.

The changes in the bone may cause a dull, constant ache, which you may worry is due to your cancer having spread to the bone. If you have dull aching in the bone that lasts for more than a few weeks, your doctors may need to do tests (a bone scan or MRI scan) to find out the cause. If the bone is weakened enough it may break (fracture) but this is very rare. The strength of your bones can be checked using a bone density scan.

It is important to be aware of the signs of bone problems so you can let your doctor know if they occur. Radiotherapy damage to the bones is uncommon, so it is likely that if you have any symptoms, they will have another cause.

Female late effects

This treatment causes infertility which is permanent and very likely to induce the menopause during the next 3 to 4 months after treatment in women who are still having regular periods. Your doctor 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 the doctor who is planning your treatment know so that this can be discussed further with you. If appropriate, they can arrange for you to see a fertility specialist urgently.

Radiotherapy can cause vaginal narrowing and dryness which can affect your sex life. However, advice will be given about lessening this problem.

Male late effects

This treatment causes infertility which is permanent. If this is a concern, please discuss this with your treating team as sperm banking options may be available. Some men may notice it is more difficult to achieve an erection following a course of radiotherapy. This is more common in men over the age of 50 and may be permanent.

Treatment is available to help this in the form of medication from your GP. If this does not suit, you can be referred to a specialist clinic.

Last updated: March 2024