Anal cancer

Expert reviewer, Dr Adam Dangoor, Consultant Medical Oncologist
Next review due January 2022

Anal cancer is a rare type of cancer that starts in the end of your bowel (the anus). It happens when cells in your anus start growing abnormally and out of control, causing symptoms such as pain and bleeding from your bottom.

About anal cancer

Anal cancer is rare – about 1,500 people were diagnosed with it in the UK in 2015. But this number has been rising in recent years, particularly in women. Your risk of anal cancer becomes greater the older you get.

There are different types of anal cancer. They include the following.

  • Squamous cell carcinoma. This is the most common type – around eight out of 10 anal cancers are this type. These cancers develop from the small flat cells that line your anal canal and your anal margin. Your anal canal is the tube that connects the lower part of your large bowel (rectum) to the outside of your body. The anal margin is the darker-coloured skin immediately surrounding the opening to your anus. Which area they start in can affect how they progress and how they’re treated.
  • Adenocarcinoma. These develop from the cells that produce mucus within your anal canal. Doctors treat it in the same way as they would rectal cancer.
  • Basal cell carcinoma. This is a type of skin cancer that can develop in the skin around your anus.
  • Malignant melanoma. This is another type of skin cancer that you can get around your anus. It starts in cells called melanocytes. Doctors treat it in the same way as other melanomas.

Symptoms of anal cancer

Symptoms of anal cancer include:

  • bleeding from your bottom – you may see blood in your faeces or on the toilet paper
  • pain around your anus
  • discharge coming from your anus
  • feeling of a small lump or lumps, or ulcers around your anus
  • feeling itchy around your anus
  • feeling like you haven’t completely finished after a bowel movement
  • difficulty controlling your bowel movements (faecal incontinence)

If you have these symptoms and they don’t seem to be getting better, see your GP. These symptoms can often be caused by other things, such as piles, but it’s worth getting them checked out by a doctor. Don’t put off getting an appointment, as cancers are generally easier to treat if caught early.

Causes of anal cancer

Up to nine in 10 cases of anal cancer are thought to be linked to infection with the human papilloma virus (HPV). This is a sexually transmitted infection, which is also associated with cervical cancer and genital warts. You’re at greater risk of being infected with HPV and developing anal cancer if you:

  • have a high number of sexual partners during your lifetime
  • have anal sex – particularly if you’re a man who has sex with other men
  • are a woman with a history of cervical cancer, or pre-cancerous changes to your cervix

There are certain other risk factors for anal cancer too. You’re at greater risk of developing it if you have HIV/AIDS, or if your immune system is suppressed for some other reason.

Women are more likely than men to develop anal cancer. You’re also more likely to get it if you smoke, and your risk increases as you get older.

Diagnosing anal cancer

Seeing your GP

Your GP will ask about your symptoms and examine you. They’ll ask about your medical history too. Your GP may ask to examine your back passage (rectum), to check whether they can feel anything wrong. They’ll do this by feeling inside your back passage with their finger (they’ll wear a glove and use lubrication). Although it might feel a little uncomfortable, it shouldn’t be painful. If you’re a woman, your GP may also ask to examine inside your vagina to check whether a tumour could have spread here.

Tests to diagnose anal cancer

Depending on what they’ve found during their examination, your GP may refer you to hospital for further tests. They may also refer you to see a doctor who specialises in conditions that affect the bowel. Tests for anal cancer involve inserting a tube into your back passage to look inside your bowel. They include:

  • a proctoscopy, using a small tube to look inside your back passage
  • a sigmoidoscopy, which uses a longer tube to look further inside your large bowel
  • a colonoscopy, to look at the whole of your large bowel

You’ll usually have these tests as an out-patient (you won’t need to stay in hospital). They can be uncomfortable, but shouldn’t normally be painful. Your doctor may take a small sample of tissue (a biopsy) during the test. They’ll send this to a laboratory for testing to find out whether the cells are cancerous or not. You may also have an examination under a general anaesthetic, to allow your doctor to do a more thorough examination and to take a biopsy.


If you’re found to have anal cancer, you will need to have more tests to find out how big it is and whether it’s spread. This process is known as staging. You may have the following tests in different parts of your body:

  • a computer tomography scan (CT scan)
  • an MRI scan
  • a PET-CT scan (a type of CT scan that uses a radioactive dye to show up cancer cells)
  • an ultrasound of your back passage
  • tests on your lymph nodes – a sample of cells can be taken with a small needle

Treatment of anal cancer

If you’re diagnosed with anal cancer, your treatment will be managed by a multidisciplinary team. This means a team of healthcare professionals with lots of different specialities, including doctors specialised in diagnosing and treating anal cancers, and specialist nurses. What treatment you will be offered will depend on the type of anal cancer you have, and how far it’s spread. Your doctor will discuss what your options are.


The most common treatment for anal cancer is a combination of chemotherapy and radiotherapy, which is called chemoradiotherapy. This uses medicines and radiation together to destroy cancer cells. It avoids the need to have surgery on your bowel.

You’ll be given a treatment plan that will be tailored to your needs, and which may vary depending on services and guidelines in your local area. You’ll usually have your treatment over the course of five weeks, with chemotherapy on the first and last weeks, and radiotherapy throughout. Most commonly, you’ll have two different chemotherapy medicines. One is given as a single injection, and the second you have as a drip into a vein in your arm on four separate days. You’ll usually have the radiotherapy every weekday for the five-week treatment period.

You’ll usually have chemotherapy in a day unit at the hospital, and radiotherapy as an out-patient. This means you won’t usually need to stay overnight in hospital. But you will need to be able to travel to the hospital every weekday, during your treatment period.


In some circumstances, your doctor may recommend you have surgery to remove your cancer. The operation you’re offered will depend on the size and position of your tumour.

Local excision

You might be offered surgery if your tumour is small and just affects the area around the opening to your anus (the anal margin). This is called a local excision. It involves removing the tumour along with some normal skin and tissue around it. As it doesn’t involve your anal sphincter muscle, you should still be able to pass faeces normally after the operation.

Abdominoperineal resection (AP resection)

You may also be offered surgery to remove your cancer if treatment with chemoradiotherapy hasn’t worked, or if your cancer has come back after treatment. It isn’t very common. The surgery, called abdominoperineal resection, involves removing your anus, rectum and part of your bowel. It’s often called ‘salvage surgery’ as it’s a second chance of curing your cancer when other treatment has failed.

As part of this operation, you will need to have a colostomy. This is when the end of your bowel is brought out through an opening in your skin and attached to the surface of your abdomen. The opening of your bowel is known as a stoma. You’ll need to wear a bag over your stoma, which will collect faeces outside your body.

It may take a while to adjust to living with a stoma, but your doctor or stoma nurse will give you help and advice. We have more detailed information on living with a stoma.

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Preventing anal cancer

Vaccination against HPV can help to protect against anal cancer. HPV vaccination is currently offered to all girls in the UK aged 12–13 to protect them from cervical cancer and genital warts. This is also due to be extended to boys aged 12–13 in 2019. You can also get the HPV vaccine free through a sexual health clinic if you’re a man who has sex with men, and you’re under 45. Anyone can also pay to have the vaccine privately through your pharmacy, health clinic, or sometimes your GP.

Other things you can do to reduce your risk of anal cancer include wearing condoms when you have sex, and giving up smoking if you smoke.

Living with anal cancer

You may need to make some changes to your diet while you’re having treatment for anal cancer. Both chemotherapy and radiotherapy can cause diarrhoea – and as you’re likely to have the two treatments together, it can make this hard to cope with. It might help to eat less fibre during your treatment, and for a few weeks afterwards while you recover. This means avoiding wholegrain cereals and breads, and fruit and vegetables that are high in fibre. Once your digestion has settled down again, you can gradually reintroduce more fibre to your diet.

If you need to have a colostomy, there’s likely to be a number of changes you’ll need to make – including to your diet. This can take a while to come to terms with. See our Related information for more information about living with a stoma.

You're likely to have a range of emotions if you've been diagnosed with anal cancer. You may feel shocked, upset or scared. As well as the emotional aspects, there can be a lot of practical issues to sort out – such as telling other people and taking time off work. Talking to your family and friends can help them to understand what you’re going through and how you’re feeling. Organisations and support groups, such as those listed in the Other helpful websites section, can also be a great source of information and support.

See our Related information section for more articles on the various aspects of living with cancer.

Frequently asked questions

  • One of the most common symptoms of anal cancer is bleeding from your back passage. This is a very common symptom of lots of other conditions too. Most of the time, the bleeding is caused by something less serious, such as piles (haemorrhoids) or an anal fissure, which can be easily treated. An anal fissure is a small tear in the lining of your anal canal. Piles (haemorrhoids) are enlarged blood vessels that you can get inside or around your anus. They feel like small lumps and can also be itchy.

    Other causes of bleeding from your bottom can include conditions that affect your bowel, such as Crohn’s disease, ulcerative colitis and diverticular disease.

    Although bleeding from your bottom is more likely to be due to one of these other conditions, it’s still important to get it checked out by your GP. Many people with anal cancer wrongly put their symptoms down to piles – but your doctor can do a simple test to check. The sooner you find out the cause of your symptoms, the sooner you can get the right treatment.

  • After you've finished your treatment, you’ll need to have regular check-ups with your doctor.

    You may need to see your doctor every six weeks at first to see if the treatment has worked. Your doctor will usually need to do a physical examination of your anus in these appointments, and less commonly, a test called an anoscopy. This involves inserting a tube into your back passage to look directly into your anus.

    Once your doctor is happy that your treatment has worked, your appointments will gradually become less frequent. Your doctor will check for any signs of the cancer returning. You may occasionally need to have other test and scans, such as an ultrasound, CT scan or MRI scan.

    If you get any symptoms between your scheduled check-ups, it's important to see your doctor as soon as possible. The doctor and specialist nurses will also be able to advise you on how to deal with any ongoing symptoms you may have due to your treatment. Some people can have problems with soreness and damage to the skin around their anus. Your doctor or nurse may be able to recommend some creams or dressing you can use.

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  • Reviewed by Pippa Coulter, Freelance Health Editor, January 2019
    Expert reviewer, Dr Adam Dangoor, Consultant Medical Oncologist
    Next review due January 2022