Anal cancer

Published by Bupa's Health Information Team, May 2010.

This factsheet is for people who have anal cancer, or who would like information about it.

Anal cancer is a lump created by an abnormal and uncontrolled growth of cells in the anus.

How cancer develops

A Flash plug-in is required to view this animation.

The anus

Your anus is the area at the very end of your bowel. Your anal canal is the tube that connects the lower part of your large bowel (rectum) to the outside of your body. It's surrounded by a muscle called the anal sphincter, which relaxes and contracts to control your bowel movements.

About anal cancer

Anal cancer is a rare form of cancer - about 850 people are diagnosed with this type of cancer each year in the UK. However, this number has been rising in recent years, particularly in women.

Types of anal cancer

There are a number of types of anal cancer.

• Squamous cell carcinoma. This develops from squamous cells - small flat cells that line your anal canal. Most anal cancers are squamous cell carcinomas.
  
• Cloacogenic carcinoma. This develops between the outer part of your anus and the lower part of your rectum, from similar cells to squamous cells.
  
• Adenocarcinoma. The transitional zone is where your anal canal meets your rectum. Here, there are squamous cells and glandular cells, which produce mucus to help faeces pass smoothly through your anus. Adenocarcinoma develops from glandular cells in the transitional zone. It's very rare.
  
• Skin cancer. Two types of skin cancer called basal cell carcinoma and malignant melanoma can occur around your anus, but these are extremely rare.

Symptoms of anal cancer

Symptoms of anal cancer include:

• bleeding from your rectum, which you may see in your faeces or on toilet paper
  
• pain in your anal area
  
• a mucus discharge from your anus
  
• small lumps around your anus
  
• itchiness around your anal area
  
• difficulty controlling your bowel movements (faecal incontinence)
  
• a lump in your groin

These symptoms aren't always caused by anal cancer but if you have them, contact your GP.

Around one in four people with anal cancer don't have any symptoms.

Causes of anal cancer

The reasons why you may develop anal cancer aren't fully understood at present. The following factors may increase your chance of getting it.

• Age - your risk of developing anal cancer increases as you get older.
  
• Gender - anal cancer is more common in women.
  
• Some types of human papilloma virus (HPV) - over eight in every 10 people who are diagnosed with anal cancer have an HPV infection in their anal area. If you have ever had genital warts, cervical or vaginal cancer (which are also associated with the HPV virus), you have a greater chance of getting anal cancer.
  
• Number of sexual partners - the greater your number of sexual partners, the more likely you are to have been infected with HPV.
  
• Anal sex - women who have anal sex and men who have receptive anal sex are at an increased risk of developing anal cancer.
  
• Smoking.
  
• A weakened immune system - for example, if you have HIV/AIDS or are taking medicines that suppress your immune system.

Diagnosis of anal cancer

Your GP will ask about your symptoms and examine you. He or she may also ask about your medical history.

Your GP may do a rectal examination, which involves inserting his or her finger inside your anus (he or she will wear a glove and use lubrication). Although a little uncomfortable, this isn't painful.

Your GP may refer you to a colorectal surgeon - a doctor who specialises in conditions that affect the bowel. He or she may use a proctoscope or sigmoidoscope to examine the area more carefully. These are narrow tubes with a light that allows your surgeon to examine the lining of your anus and rectum and if necessary, take a biopsy. A biopsy is a small sample of tissue. This will be sent to a laboratory for testing to determine whether the cells are malignant (cancerous) or benign (not cancerous).

If these tests show that you have anal cancer, further tests will be arranged to see how big the cancer is and whether it has spread. These might include:

• a CT scan
  
• an MRI scan
  
• an ultrasound scan of your abdomen or a rectal ultrasound, where a small probe is passed into your anus

Treatment of anal cancer

There are several different types of treatment for anal cancer, depending on how big the cancer is and whether it has spread.

Non-surgical treatments

The most common form of treatment for anal cancer is a combination of chemotherapy and radiotherapy. This is known as chemoradiation. The treatments may be given to you at the same time or following one another.

Chemotherapy uses medicines to destroy cancer cells.

Radiotherapy uses X-rays to destroy cancer cells. Occasionally internal radiotherapy (brachytherapy) may be used, which involves your doctor temporarily placing radioactive wires in the area of the cancer.

Surgery

There are two types of surgery that can be used to remove anal cancer. The operation you have will depend on the size and position of your cancer.

An operation called a local resection is used to remove small tumours and some of the surrounding tissue. This can only be done if your anal sphincter won't be affected by the surgery. This type of surgery usually doesn't affect your ability to pass a bowel movement.

Alternatively, your anus, rectum and part of your bowel can be removed. This is called an abdominoperineal resection (AP resection). Without your rectum and anus you won't be able to pass a bowel movement, so the end of your bowel will be brought out onto the skin on the surface of your abdomen. This is called a colostomy and the opening of your bowel is known as a stoma. You will wear a bag over the stoma, which will collect faeces outside your body. It may take a while to adjust to living with a stoma, but people with colostomies are able to live normal lives.

Prevention of anal cancer

One way to reduce your risk of getting anal cancer is to avoid getting HPV, which is passed on through sexual contact. It's important to remember that you can have HPV but not have genital warts or any other symptoms. To reduce your risk of HPV infection:

• use condoms when having sex
  
• limit the number of sexual partners you have
  
• don't have anal sex

If you smoke, try to stop as this will reduce your risk of getting anal cancer. If you're having trouble giving up, contact your GP for advice.

For answers to frequently asked questions on this topic, see Common questions.

For sources and links to further information, see Resources.