Anal Cancer

What is anal cancer?

Anal cancer is a tumour that develops in the last 5cm of the bowel. It is completely different from colorectal cancer, which occurs much higher up in the gut.

How common is anal cancer?

Anal cancer is generally a rare disease. The rate at which it occurs varies considerably:

Population Rate / 100,000 population
Anal cancer in the general population 1
Anal cancer in "never married" men (pre-HIV) 35
Anal cancer in HIV-positive gay men 60


in comparison...

Cancer Rate / 100,000 population
Rates of prostate cancer (the commonest cancer in all men) 150
Rates of colorectal cancer in Australian men 46


Anal cancer rates appear to be increasing in both men and women.

What are the risk factors?

The following factors may increase someone's risk of anal cancer:

  • Certain types of anal wart virus infection
  • Practising receptive anal intercourse
  • Smoking cigarettes
  • Having a history of an abnormal cervical Pap smear
  • Increasing age – it is very rare in under 40 years (unless HIV+)
  • HIV infection

What symptoms do people get?

Usually no symptoms, for the first few years. This is why the condition often not noticed until it is at an advanced stage. If symptoms do develop, they may include:

  • Bleeding from the rectum
  • A sensation of incomplete emptying of the bowel
  • Noticing a lump inside or around the anus
  • Rectal discharge

Are there any screening tests?

A simple examination of the anal canal with a lubricated, gloved finger can often be useful in initially making the diagnosis. this can be done by your general practitioner or specialist. You may wish to consider learning to do this yourself.

The screening roles of anal Pap smear testing and high resolution anoscopy is still being evaluated.

What treatments are available?

Treatment is usually one or several of the following: surgery, radiotherapy and chemotherapy.

What are the survival rates?

The five-year survival is 65-75%. Anal cancers diagnosed early thend to respond better to treatment than those seen later. Being HIV-negative also improves the prognosis.

Where can I get further information?

Your general practitioner should be able to give you some very useful advice. Also, the Medical Center at the University of California, San Francisco has a good website.