What is anal cancer?

The anus is the name for the muscular area at the very end of the large bowel. It is the muscle which opens and closes to control bowel movements, and is where the bowel opens to the outside of the body. This muscle is also called a sphincter.

The most common type of anal cancer is squamous cell. Other, rarer types are basal cell, adenocarcinoma and melanoma. This section deals with the treatment of squamous cell carcinoma.

What causes anal cancer?

Cancer of the anus is rare. It is slightly more common in women than in men. As with most cancers the cause of anal cancer is unknown. It is known that anal cancer is more likely to develop in people who have had a particular virus infection called the human papilloma virus (HPV). The risk of having HPV increases with the number of sexual partners you have. Anal cancer is also more common in people who have a lowered immunity due to medical conditions, such as HIV. Cigarette smoking may also increase a person’s risk of developing anal cancer.

Signs and symptoms

The most common symptoms of anal cancer are bleeding from the rectum, and pain. Some people develop small firm lumps which may be confused with piles (haemorrhoids). Some people have discomfort, itching and a discharge of mucous (a jelly-like substance) from the anus. Faecal incontinence (a reduced ability to control bowel function) may also occur. Occasionally anal cancer can appear as an ulcerated area and may spread to the skin of the buttocks.

How it is diagnosed

Before your doctor can make a firm diagnosis of anal cancer a number of tests will have to be done. These are listed overleaf.

Rectal examination  This is also sometimes known as a PR examination and is where the doctor examines your back passage with a gloved finger.

Biopsy  A small sample of cells is taken from the tumour so that it can be examined under a microscope. Usually this involves using either a special biopsy device (known as a punch biopsy) or the doctor can cut a small piece away from the tumour (known as an incisional biopsy). This can be done under local or general anaesthetic.

X-rays  These may be taken to show if there has been any spread of the cancer.

Ultrasound scan  A simple, painless scan which uses sound waves to form a picture of the inside of the abdomen.

CT (computerised tomography) scan  This is a more sophisticated type of x-ray which builds up a three-dimensional picture of the inside of the body. The scan is painless but takes longer than an x-ray (10-30 minutes). It may be used to identify the exact site of the tumour or to check for any spread of the cancer. Most people who have a CT scan are given a drink or injection to allow particular areas to be seen more clearly. Before having the injection or drink, it is important to tell the person doing this test if you are allergic to iodine or have asthma.

MRI (magnetic resonance imaging) scan  This test is similar to a CT scan, but uses magnetic fields instead of x-rays to form a series of cross sectional pictures of inside the body. During the scan you will be asked to lie very still on the couch inside a metal cylinder. You will usually be given an injection to allow the pictures to be seen more clearly.

The test can take about 30 minutes and is completely painless, although the machine is quite noisy. If you don’t like enclosed spaces you may find the machine claustrophobic. You will be given earplugs or headphones and you can usually take someone with you into the room to keep you company. A two-way intercom enables you to talk with the people controlling the scanner. Before entering the scanning room you will be asked to remove anything metal, such as jewellery, as this may affect the scanning machine. If you have had any operations to insert metal objects such as a hip replacement or a pacemaker it is important to tell the person doing the scan before entering the scanning room.


The stage of a cancer is a term used to describe its size and whether it has spread beyond its original site. Knowing the particular type and the stage of the cancer helps the doctors to decide on the most appropriate treatment.

Cancer can spread in the body, either in the bloodstream or through the lymphatic system. The lymphatic system is part of the body’s defence against infection and disease. The system is made up of a network of lymph glands (also known as lymph nodes) that are linked by fine ducts containing lymph fluid. Your doctors will usually check the nearby lymph nodes when staging your cancer.

  • Stage 1  The cancer only affects the anus and is smaller than 2cm in size. It has not begun to spread into the sphincter muscle.
  • Stage 2  The cancer is bigger than 2cm in size but has not spread into nearby lymph nodes or to other parts of the body.
  • Stage 3A  The cancer has spread to the lymph nodes close to the rectum, or to nearby organs such as the bladder or vagina.
  • Stage 3B  The cancer has either spread to the lymph nodes in the groin and pelvis, or to the lymph nodes close to the anus as well as nearby organs, such as the bladder or vagina.
  • Stage 4  The cancer has spread to lymph nodes in the abdomen or to other parts of the body, such as the liver.

If the cancer comes back after initial treatment, this is known as recurrent cancer.


Grading refers to the appearance of the cancer cells under the microscope and gives an idea of how quickly the cancer may develop. Low-grade means that the cancer cells look very like the normal cells. They are usually slow-growing and are less likely to spread. In high-grade tumours the cells look very abnormal, are likely to grow more quickly and are more likely to spread.


The main types of treatment used for anal cancer are a combination of radiotherapy and chemotherapy, which may be given at the same time or following one another. This combination of treatment is usually very successful. Surgery is not often used as the first choice of treatment for anal cancer.


High-energy rays are used to destroy cancer cells, while doing as little harm as possible to normal cells. The treatment is often given for a few minutes each weekday for several weeks.

During the treatment period you may have changes in your bowel function such as diarrhoea, or passing wind: these side effects can sometimes be reduced by avoiding particular foods. CancerBACUP’s section on diet and the cancer patient contains more information about this. Towards the end of the treatment period you may have blistering and soreness of the skin around the anal area, and possibly in the groin areas too. Extreme tiredness, or fatigue, is a common side effect of radiotherapy too.

These side effects usually decrease gradually once the treatment has ended, but it may take some months for skin changes to go back to normal. A small proportion of people find that their bowel function is permanently altered, and it is important to discuss this with your doctor as it is often possible to find ways of reducing any problems. Your doctor or a dietitian at the hospital can give you advice.

Other potential side effects that can occur after radiotherapy for anal cancer include narrowing of the vagina (vaginal stenosis), and dryness. To help prevent this, women will be asked to use a vaginal dilator with a lubricating jelly to keep the vaginal walls open and supple. Some women may also need to use lubricating jelly during sexual intercourse.

Infertility can also be a side effect of radiotherapy. If you are concerned about your risks of being infertile following treatment, it is a good idea to discuss this issue with your specialist before starting.


This is the use of anti-cancer drugs to destroy cancer cells. The chemotherapy drugs are usually given by injection into a vein (intravenously). They can temporarily reduce the number of normal cells in your blood. When your blood count is low you are more likely to get an infection and you may tire very easily. During chemotherapy your blood will be tested regularly and, if necessary, you may be given antibiotics to treat any infection. Blood transfusions may be given if you become anaemic due to chemotherapy.

Other side effects may include feeling sick (nausea) and vomiting. If you do feel sick you might find our section on controlling nausea and vomiting helpful.

Some chemotherapy drugs can also make your mouth sore and cause small mouth ulcers. Regular mouthwashes are important and your nurse will show you how to use these properly. If you don’t feel like eating meals, you can supplement your diet with nutritious drinks or soups. A wide range of drinks is available and you can buy them at most chemists. You can ask your doctor to refer you to a dietitian for advice about your diet.


Surgery may be used if initial treatment does not completely get rid of the cancer, or if there are signs that your cancer has returned. There are two main types of surgery: local resection and abdominoperineal resection.

Local resection  This may be used for small tumours on the outside of the anus. This operation only removes the area of the anus containing the cancer cells. The muscle that opens and closes the anus to allow the faeces to be passed normally is not usually affected, and so normal bowel function is maintained for most people.

Abdominoperineal resection  This is the removal of the anus and rectum. This operation requires a permanent colostomy, which involves diverting the open end of the bowel on to the surface of the abdomen (tummy area), to allow faeces to be passed out of the body into a colostomy bag. The opening on the abdominal wall is known as a stoma.

CancerBACUP can send you information about having a colostomy. Although the idea of a colostomy is initially frightening and distressing for many people, most people find that they adapt over time and can return to normal activities. You will be able to get support and advice from the stoma nurse in your hospital

Relieving symptoms following treatment

It is not unusual for people to find that they have distressing side effects for a time following treatment for anal cancer. Some people find that they have diarrhoea and occasional incontinence, as well as a feeling of bloatedness and wind. These symptoms are usually temporary but may last for up to several months.

CancerBACUP’s section on diet and the cancer patient contains information on how to cope with these problems and your cancer specialist and dietitian can give you further advice.

Your feelings

During your diagnosis and treatment you are likely to experience a number of different emotions, from shock and disbelief to fear and anger. At times these emotions can be overwhelming and hard to control. It is quite natural, and important, to be able to express them.

Everyone has their own ways of coping with difficult situations; some people find it helpful to talk to friends or family while others prefer to seek help from people outside their situation. Others prefer to keep their feelings to themselves.

There is no right or wrong way to cope; but help is available if you need it. CancerBACUP has a section which discusses the emotional effects of cancer and how to deal with them.


This section has been compiled using information from a number of reliable sources including;

  • Oxford Textbook of Oncology (2nd edition). Souhami et al. Oxford University Press, 2002.
  • Gastrointestinal Oncology: Principles and Practice. Kelsen et al. Lippincott Williams and Wilkins, 2002.
  • The Textbook of Uncommon Cancers (2nd edition). Raghavan et al. Wiley, 1999.

For further references, please see the general bibliography.

No. Diabetes is a common condition and surgeons are used  to operating regularly on people who are diabetic. Usually they will put up a drip, into a vein in the arm or back of the hand, before the operation. This will then be used to give insulin and sugar solutions to keep your blood sugar at the correct level throughout the operation and will continue until you can eat and drink normally. Throughout this time your blood sugar level will be regularly checked and the drip adjusted as necessary. This means it will be perfectly safe for you to go ahead with the surgery that you need.

I am due to have a major operation to remove a cancer. I am very worried, because I am diabetic and need to eat regularly. Does this mean I won’t be able to have the surgery?

Understandably, ‘nothing more to be done’ is a phrase that can cause alarm, despondency and despair. So it is important to be clear just what this means. It isn’t the end of care and support for your relative. What it does mean is that their specialists do not think there is any treatment left that has a reasonable chance of actually controlling the cancer. There is no further ‘active’ treatment, that is treatment which is given to contain or reduce the cancer, that they can usefully offer.

This decision will change the emphasis of your relative’s medical care from ‘active treatment’ to ‘supportive care’. Their GP, Macmillan nurses and the team from the local hospice team will become more involved and you may find that the hospital will play a smaller part than before.

The emphasis of care is attention to easing, and preventing, upsetting symptoms of the cancer and giving practical support, both physically and emotionally, to your relative and the family. Quality of life will become most important and, perhaps surprisingly, people with advanced cancer often find that at this late stage of their illness their quality and enjoyment of life can actually improve.

Part of this improvement can be because they no longer have the inconvenience of regular hospital visits and tests and the physical effort and burden this may involve when faced with an advanced cancer. Less disruption to a person’s daily life, and not having to cope with the often unpleasant side effects of treatment can be a benefit, particularly if the treatment is not helping to control the cancer.

It is natural to feel despair when the specialists say there is nothing more that can be done. So your question is one that is frequently asked. Very often, however, it is asked by relatives and not by the person who actually has the cancer. Sometimes this is because that person has come to terms with their condition and is quite willing, and possibly even relieved, to go along with the change in their care. At the same time their relatives, with the best of intentions, still feel they shouldn’t ‘give up’ and that ‘something must be done’. If your relative is still looking for active treatment there are two things they can do.

The first is for your relative to talk to their specialist (a phone call to his or her secretary should easily arrange this). They can ask about any experimental treatments and clinical trials that may be suitable. It may be that they will say there really is nothing to be offered or they may tell them about new or experimental treatments which are being tested at another hospital and might offer to refer your mother there for advice.

There are always new drugs and treatments being tested for cancer, unfortunately many of these do not prove to be successful or the benefits are likely to be small. Despite this reality, many new experimental treatments do get enthusiastic reports in the media, which all too often raise false hopes for patients and their families. Sadly this happens frequently.

However having active treatment helps some people feel positive and hopeful even though they know the chances of benefit are small. People sometimes find it easier to cope if they feel they are doing something active to try and treat the cancer, and many people are also happy to be contributing to the advancement of knowledge about cancer and its treatment. The downside is the disruption, and possible distress, from treatment and its side effects that your relative might have to go through. Also, even when there is a response to these treatments it is, at best, usually a matter of prolonging life by a few weeks or months.

If your relative doesn’t want to see the specialist, or if they feel the interview was not satisfactory, then the second thing you or they can do is ask the consultant or GP to arrange a second opinion from a consultant at another hospital. Doctors are usually happy to do this, as they appreciate a persons need to find any available treatment that may help. Even if you do this, however, it is likely that the new specialist will not be able to offer anything more. But at least you will then know that they have explored every possible avenue for their future care.

My relative has been told that their treatment is no longer working and that there is nothing more that can be done, they have had lots of different treatment. Is this right, what about all the treatments I read about in the papers?

When someone has incurable cancer it is very natural that their relatives want to know how long they might live for (even if the patient themselves does not want to know) so that they can plan and start to come to terms with such a distressing situation.

Unfortunately it is usually difficult, even for the most experienced cancer specialist, to give an accurate answer. This is because every patient is a unique individual and will be affected differently by their illness. Even two people of the same age, with the same type of cancer, which has spread to the same extent, can have very different survival times. This can happen because many other things influence survival including general fitness, will power, the response to treatment and the development (or avoidance) of unexpected complications.

Despite all this, if the doctor knows the type of cancer and how far it has spread then they will be able to offer ‘average’ figures for life expectancy. But, very importantly, these are only averages. This means that some people will live a little longer, and a few will live a lot longer, than predicted, whilst others may survive a shorter time.

So, in many ways, even an expert opinion of life expectancy for any individual patient is little more than informed guess.

Sometimes, however, even if doctors explain the uncertainties, patients and their relatives will still put great faith in the time they have been given. (This can then lead to problems if someone deteriorates sooner than expected).

Because of this uncertainty some doctors are reluctant to offer survival times to their patients (or to relatives). Most specialists, however, will be prepared to discuss the issue, realising that people do need some idea of time scales in order to plan their lives and cope with things. But their advice is still only a guide to what might happen and not a precise forecast of what will happen.

My husband has been told he has incurable cancer. I have asked the doctor how long he might live but his answers seem very vague. Why can’t he be more precise?

Anal cancers are rare with only about 300 new cases in the UK each year.

Despite the small numbers several different types of cancer can occur in the anal region.

The majority of these (more than 4 out 5) arise in the lining cells of the wall of the anus or the skin around the opening of the anus (the anal margin). These cancers are called squamous carcinomas.

In the past pathologists have described several types of cancer which when seen under the microscope look slightly different from normal squamous carcinomas. These include transitional, cloacogenic and basaloid carcinomas. Despite their differences in appearance these growths all seem to behave exactly like squamous carcinomas and so are treated in exactly the same way.

Other cancers that may occur in the anal region include adenocarcinomas, malignant melanomas and basal cell carcinomas. These cancers do behave differently to the squamous carcinomas and require different approaches to treatment.

My mother has been told she has a basaloid anal cancer. What is this

The anus is the name for the muscular area at the end of the large bowel. It includes the muscle, which opens and closes to control bowel movements, and is where the bowel opens to the outside. The internal part of the anus is called the anal canal.

The anal canal is quite short, being a cylinder of tissue about 2-3 centimetres long (about one inch). This means that any operation to remove a cancer of the anal canal will have to take away the whole of the anal canal to be sure of clearing the growth. This surgery includes the removal of the muscle controlling bowel movements and so leads to permanent incontinence. Because of this a colostomy is always necessary afterwards (this involves bringing the end of the bowel out on to the front of the abdomen and having a bag to collect the faeces). The skin where the anus was is then sown together.

This is obviously quite a big operation and also has the disadvantage that your mother would be left with a colostomy for the rest of her life.

During the 1980s doctors wondered whether giving radiotherapy, together with chemotherapy, might offer an alternative to surgery for squamous caricnomas of the anal canal. Clinical trials have now shown that the chance of cure with this non-surgical treatment is every bit as good as with an operation. Although it does involve quite a lot of treatment over a period of several months it does, of course, avoid the need for a colostomy.

Another point worth bearing in mind is that if your mother was one of the unfortunate minority of people for whom the radiotherapy and chemotherapy failed to completely clear the cancer, so that it came back at a later time, then an operation could always still be done, giving another chance of a cure.

My mother has been told she has a squamous cancer in her anal canal. Her doctors have recommended a long course of radiotherapy and chemotherapy. Wouldn’t an operation be better?

Cancer of the anus is quite rare with only about 300 new cases in the United Kingdom each year. Like most cancers the cause for the great majority of anal cancers is unknown.

A minority of anal tumours are, however, associated with infection by a virus called the human papilloma virus (HPV). This virus can cause warts in the genital area and very occasionally, often after many years, a cancer may develop in one of these warts. Anal cancer is commoner in the receptive partners of anal intercourse and HPV infection may be a factor in this.

Anal cancer is also commoner in people who have AIDS. No one is sure whether this is due to the presence of the HIV virus (the human immunodeficiency virus, which causes AIDS) or whether the reduced immunity of AIDS patients makes them ore at risk to the possible cancerous effects HPV.

My uncle has been told he has an anal cancer. A friend has said these cancers are caused by a virus. Is this true?

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What is anal cancer?

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