What is anal cancer?

The anus is part of the large bowel, which is part of the digestive system. In the UK, about 1,200 people develop anal cancer each year. It is slightly more common in women than men.

We have more information about other types of bowel cancer including:

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23 Feb 2017
This booklet is about anal cancer. The anus is part of the large bowel, which includes the colon and rectum.

Types of anal cancer

There are different types of anal cancer. Knowing the type helps your doctor plan your individual treatment.

Symptoms of anal cancer

Signs and symptoms of anal cancer include bleeding from the anus and pain, discomfort and itching.

If you have symptoms that do not improve within a few weeks, or if your symptoms are getting worse, it is important for your GP to refer you to a specialist. The specialist can arrange tests to find out what the problem is.

Causes of anal cancer

Doctors do not know the exact causes of anal cancer. But there are risk factors that can increase your chance of developing it.

Having one or more risk factors does not mean you will get anal cancer. Also, having no risk factors does not mean you will not develop anal cancer.

Most anal cancers are caused by the human papilloma virus (HPV), a common infection that is passed on through sexual contact. Almost everyone will have HPV at some point. But not everyone will develop anal cancer.

Diagnosis of anal cancer

People who have symptoms usually begin by seeing their GP.

Your GP may give you the following tests:

  • Rectal examination

    A rectal examination is when your doctor feels for any lumps or swelling by putting a gloved finger into your back passage (rectum).

  • Blood test

    You usually have a blood test to check for low blood cells (anaemia) and to check liver and kidney function.

If your GP thinks you might have cancer or do not know what is causing the symptoms, you should be seen at the hospital within 14 days. You will be referred to a surgeon or a specialist in bowel conditions (gastroenterologist).

At the hospital

At the hospital, the specialist will ask about your general health and any previous medical problems. They will feel your tummy and examine your back passage in the same way your GP did. They will examine the area for any signs of cancer. In women this usually includes an internal examination of the vagina as it is very close to the anal canal. Then they will talk to you about the tests you need to have.

Anal examination and biopsy

You will have an examination and a biopsy taken. A biopsy is where the doctor removes a small sample of cells from any abnormal areas, so they can be examined under a microscope. You will have this under general or local anaesthetic.

Waiting for tests results can be a difficult time, we have more information that can help.

Further tests for anal cancer

If the biopsy shows you have anal cancer, you will need further tests. You have these to find out more about the position of the cancer and to see if it has spread.

You may have the following tests:

  • CT scan

    A CT (computerised tomography) scan uses x-rays to build a three-dimensional (3D) picture of the inside of the body.

  • MRI (magnetic resonance imaging) scan

    An MRI scan uses magnetism to build up a detailed picture of areas of your body.

  • Anal ultrasound scan

    An anal ultrasound scan is when a doctor passes a small probe that makes sound waves into your back passage (rectum). The sound waves form a picture of the area. It takes about 15 to 30 minutes. This can be uncomfortable, so let your doctor know if you have any pain.

  • Fine needle aspiration (FNA) of the lymph nodes

    You may have an FNA of the lymph nodes test to check if there are any cancer cells in the lymph nodes. Or you may have it if the lymph nodes in your groin are larger than normal. The doctor passes a fine needle into the lymph node and withdraws (aspirates) some cells into a syringe.

  • PET-CT scan

    A PET-CT scan is a combination of a CT scan, which takes a series of x-rays to build up a three-dimensional picture, and a positron emission tomography (PET) scan. A PET scan uses low-dose radiation to measure the activity of cells in different parts of the body.

Stages of anal cancer

The results of your tests help your doctors find out more about the size and position of the cancer and whether it has spread. This is called staging.

A doctor decides the grade of the cancer by how the cancer cells look under the microscope. This gives an idea of how quickly the cancer might grow or spread.

Knowing the stage and grade helps your doctors plan the best treatment for you.

Treatment for anal cancer

A team of specialists will meet to discuss the best possible treatment for you. This is called a multidisciplinary team (MDT).

Your doctor will explain the different treatments and their side effects. They will also talk to you about the things you should consider when making treatment decisions.

Surgery may be your main treatment if you have a very small tumour outside the anus (anal margin).

Chemoradiation is often the main treatment for anal cancer. This is a combination of radiotherapy and chemotherapy.

You may have radiotherapy on its own if you cannot have chemoradiation. If the cancer has spread to other parts of the body chemotherapy can be used to help to control it and relieve symptoms.

You may also have some treatments as part of a clinical trial.

After anal cancer treatment

Follow-up after treatment for anal cancer

The aim of follow-up care is to make sure everything is going well and to find out if you have any concerns. The appointments are usually every few months in the first year.

We have more information on follow-up care after treatment.

Sex life

Anal cancer treatments can have a direct effect on your sex life. After treatment, the way you experience sex may change, or you may feel self-conscious about changes to your body. These changes can go back to normal over time, but sometimes they are permanent. It can take some time for you to adjust.

Talk to your doctor or nurse about sexual difficulties or concerns. They will be used to talking about these issues.


Some cancer treatments can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.

Well-being and recovery

Even if you already have a healthy lifestyle, you may choose to make some positive changes after treatment. We have more information on leading a healthy lifestyle after treatment.

How we can help

Macmillan Grants

If you have cancer, you may be able to get a Macmillan Grant to help with the extra costs of cancer. Find out who can apply and how to access our grants.

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