What is anal cancer?

Clinical Oncologist Katherine Aitkens explains bowel cancer (which includes anal cancer), giving an overview of bowel cancer symptoms, diagnosis and treatment.


Anal cancer is a cancer that starts in the anus. The anus is part of the large bowel which is part of the digestive system. In the UK, about 1,484 people develop anal cancer each year. It is more common in women than men.

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Types of anal cancer

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

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

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Symptoms of anal cancer

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

If you have symptoms that do not improve within a few weeks, or if your symptoms get 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.

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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 papillomavirus (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

If you have symptoms, you will usually begin by seeing your GP. They may do some of the following tests:

  • Rectal examination

    A rectal examination is when the doctor places a gloved finger into your back passage to feel for any lumps or swelling.

  • Blood test

    You usually have blood test to check your level of red blood cells. The tests also check how well your liver and kidneys are working.

Your GP can refer you to a hospital specialist. This is usually either 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. Then they will talk to you about the tests you need to have. Women will probably also have an internal examination of the vagina, as it is very close to the anal canal.

Anal examination and biopsy

You will have an anal examination and 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 test results can be a difficult time, we have more information that can help.

Further tests for anal cancer

If any of your biopsies show that there is cancer in the anus, you will have more tests. The results will help you and your doctor decide on the best treatment for you. You may have any of 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. 

  • 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. 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.

Staging and grading 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 cancer doctor or specialist nurse will explain the different treatments and their side effects. They will also talk to you about things to consider when making treatment decisions.

We have more information on treatments for anal cancer.

Anal cancer treatments include:

  • Chemoradiation

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

  • Radiotherapy

    You may have radiotherapy on its own if you cannot have chemoradiation.

  • Chemotherapy

    If the cancer has spread to other parts of the body chemotherapy can be used to help to control it and relieve symptoms.

  • Surgery

    Surgery may be your main treatment if you have a very small tumour; or may be used before or after other treatments.

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 follow-up appointments usually continue for up to five years. You have them less often as time goes on.

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

You may get anxious between appointments. This is natural. It may help to get support from family, friends or a support organisation. 

Macmillan is also here to support you. If you would like to talk, you can: 

Sex life

Anal cancer and its treatment can affect your sex life. Many people find it difficult to talk about this because they feel embarrassed or self-conscious. Your doctor or nurse will be used to talking about these issues. So it can help to talk to them if you are having problems with your sex life.


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 lifestyle changes after treatment.

Making small changes such as eating well and keeping active can improve your health and wellbeing and help your body recover.

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About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Date reviewed

Reviewed: 30 April 2020
Next review: 30 April 2023

This content is currently being reviewed. New information will be coming soon.

Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.