This page has been produced for patients diagnosed with anal cancer. It aims to help you understand the patient pathway and make you aware of the various treatment options that might be available to you.

What is an anal cancer?

The tissues and organs of the body are made up of cells. Cells age and become damaged and need to repair and reproduce themselves continuously. When this process gets out of control, the cells reproduce and multiply to form an abnormal mass (or tumour). Tumours can be benign (not cancerous) or malignant (cancerous). A malignant tumour consists of cancer cells that can spread to other organs in the body.

The anus is the name for the muscular area at the very end of the large bowel. It is controlled by a ring of muscle called a sphincter that opens and closes to control bowel movements. The area that connects the anus to the rectum (back passage) is called the anal canal and is around 3cm to 4cm long. The most common type of anal cancer is squamous cell carcinoma. Other rarer types are basal cell carcinoma, adenocarcinoma and melanoma. The cause of anal cancer is still unknown, but there are several factors which may increase the risk of developing the disease.

Individuals may be at greater risk if they have had a viral infection called the Human Papilloma Virus (HPV).

  • The risk of having HPV increases with the number of sexual partners you have had
  • People who have anal intercourse are also more likely to develop anal cancer. This may because they are more likely to have anal HPV

Other risks include:

  • A lowered immune response as a result of another condition or treatment for other illnesses which suppress the body’s natural immune system such as in HIV or following organ transplantation
  • Smoking tobacco had been shown to increase the risk of developing many cancers, including cancer of the anus


Rectal examination

This is sometimes known as a PR examination. A doctor will examine your back passage with a gloved finger. Women may also have an internal examination of their vagina, as the vaginal wall is very close to the anal canal.


The doctor will put a thin tube into your back passage to examine the anal canal and rectum. This is called a proctoscopy. A small sample of tissue is taken from the tumour. The tissue sample (biopsy) will be examined under a microscope. This may be done under a local or general anaesthetic (while you are asleep).


To help us decide how to treat the cancer it is very important that we get the necessary information about the cancer and the rest of the body. We call this gathering of information ‘staging investigations’ - this may involve several tests which include:

Computerised Tomography (CT) scan of your chest, abdomen and pelvis

CT is a detailed X-ray examination of the body. This examination will look for obvious abnormalities elsewhere in your body and in particular to see if there is any evidence that the cancer may have spread.

Magnetic Resonance Imaging (MRI) scan of your pelvis

MRI is a scan using magnetic waves to create images of the body. It will give a detailed picture of the tissues of the rectum, anus and pelvis. It gives us further information to help decide on the best form of treatment for you.

Staging of anal cancer

Knowing what stage a cancer is at will help the doctors decide on the most appropriate treatment pathway for you. Anal cancer tumours usually remain localised.

However, cancer cells can spread beyond the tissue of the anus and throughout the body via the blood stream, and/or through the lymphatic system.

This is a network of lymph glands (nodes) linked by fine ducts that carry the lymph fluid around the body as part of the body’s defences against disease and infection. When cancer cells enter the lymph nodes, they can cause them to swell which is why they are checked as part of the cancer staging investigations.

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 the lymph nodes or other parts of the body.

Stage 3

The cancer has spread in to the lymph nodes or to nearby organs such as the vagina or bladder.

Stage 4

The cancer has spread into the lymph nodes and to other more distant parts of the body such as the liver.

Grading of the cancer cells is a means to describe how quickly they grow and spread, with the lowest grading describing the slowest growing type of tumour.

TNM staging system

Your consultant may use the more complex TNM method of describing your cancer:

Tumour - the stage of the tumour and whether it has spread to the lymph nodes.

Nodes - the extent to which the lymph nodes are involved.

Metastases - the extent of distant metastatic disease; also known as secondaries.

The Multidisciplinary Team (MDT)

All of your results will be discussed at a colorectal and anal cancer specialist multidisciplinary team meeting. This meeting takes place once a week and is attended by consultant colorectal surgeons, a consultant radiologist, a consultant histopathologist, a consultant clinical oncologist, colorectal clinical nurse specialists and other members of the colorectal team.

At this meeting the specialist team will use their expertise to determine what will be the most effective and appropriate form of treatment for you.


You will be offered an appointment with a consultant surgeon or oncologist to discuss the treatment options open to you. You will be actively involved in any decision making and your views and wishes will be respected at all times.

Specialist teams are not present in every hospital and you may have to travel to another hospital to receive the treatment you need.

Radiotherapy and chemotherapy

Anal cancer can be treated by a combination of radiotherapy and chemotherapy, given either one after the other or together.

Radiotherapy uses repeated treatments of high-energy X-rays in small doses to kill cancer cells. Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. Chemotherapy drugs are usually given by injection into the vein (intravenously).

Further information booklets are available regarding radiotherapy and chemotherapy treatments. These booklets give detailed information about what the treatments involve and possible side-effects.

Surgery for anal cancer

Surgery is usually reserved for occasions when the cancer has spread, the initial treatment has not completely destroyed all of the cancer cells or if the disease has returned (recurrence).

Local resection

This removes small tumours on the outside of the anus and does not affect the sphincter muscle. The bowel will continue to work in the same way, as normal for most people.

Abdomino-perineal excision (APER)

For higher stages of disease, this operation removes the anus and rectum completely and requires the formation of a permanent colostomy. A colostomy (stoma) is the end of the colon brought to the surface of your abdomen and stitched to the skin.

Stools are then passed though the stoma and collected in a bag that covers it.


If an APER is recommended for you a further information leaflet is available to explain this procedure.

What if my cancer has spread?

Sometimes anal cancers can spread to other organs in the body, most commonly the liver and/or lungs. If this is shown to be the case on your staging scans, then the treatment which can be offered will be dependent on the extent of the metastases.

In some circumstances it may be possible to offer surgery or other specialist therapies to treat metastases. These operations and therapies are not performed by the Gloucestershire Hospitals NHS Foundation Trust so patients would be referred to other specialist units.

Palliative treatment

If the spread of the cancer to other organs is extensive, or you have decided to decline surgery or you are medically unfit for major surgery, then you may be offered palliative radiotherapy and/or chemotherapy. This may help to control your symptoms and slow down progression of the disease, but this will not be a cure.

Formation of a stoma

If it is not possible to offer you a treatment to cure your cancer but you are getting a lot of adverse symptoms from your bowel, you may be offered an operation to form a stoma. The aim of this would be to relieve your symptoms.

Best supportive care

If you are not medically fit to have any of the described treatments or you decide to decline treatment then you will be offered palliative or best supportive care. This is a treatment plan to relieve symptoms and aims to enhance quality of life for as long as possible.

Patient support

Being diagnosed with anal cancer will come as a shock to most people. As you progress through your treatment pathway, you are likely to experience a rollercoaster of emotions and you will have lots of questions and concerns and often some difficult decisions to make. The colorectal clinical nurse specialist team, alongside our specialist radiotherapy and oncology teams will be able to offer you information and advice about your diagnosis and treatment as well as providing ongoing support.

Contact information

Colorectal Nurse Specialist

Gloucestershire Royal Hospital

Tel: 0300 422 5617

Monday to Friday, 8:00am to 4:00pm

Outside of these hours, please leave a message and someone will return your call the next working day.

Stoma Nurse Specialist

Cheltenham General Hospital

Tel: 0300 422 4363

Monday to Friday, 8:00am to 4:00pm

Gloucestershire Royal Hospital

Tel: 0300 422 6702

Monday to Friday, 8:00am to 4:00pm

Outside of these hours, please leave a message and someone will return your call the next working day. Patient


If you have an urgent problem, the stoma nurses can be contacted via the hospital switchboard.

Hospital Switchboard

Tel: 0300 422 2222

When prompted, ask for the operator then for the stoma nurses.

Further information

Macmillan Cancer Support

Tel: 0808 808 00 00

Monday to Friday, 9:00am to 8:00pm


Bowel Cancer UK


FOCUS Cancer Information Centre

Cheltenham General Hospital

Tel: 0300 422 4414

Monday to Friday, 8:30am to 4:30pm

Maggie’s Centre

College Baths Road, Cheltenham

Tel: 01242 250 611

Monday to Friday, 9:00am to 5:00pm

‘Mini’ Maggies

The Main Place, Old Station Way, Coleford, GL16 8RH

Tel: 01242 250 611

Sessions run on the third Friday of each month from 10:00am to 2:00pm

Macmillan Information Hub

Gloucester Royal Hospital

Tel: 0300 422 8880

Monday to Friday, 9:00am to 4:00pm


Printable version of this page

Anal cancer GHPI1251_11_22 Department: Colorectal Review due: November 2025 PDF, 351.4 KB, 8 pages
Reference number GHPI1251_11_22
Department Colorectal
Review due November 2025