Anal Cancer: Risk Factors and Prevention

Approved by the Cancer.Net Editorial Board, 03/2014

ON THIS PAGE: You will find out more about the factors that increase the chance of developing this type of cancer. In addition, this page includes information on how to reduce your risk of getting anal cancer. To see other pages, use the menu on the side of your screen.

A risk factor is anything that increases a person’s chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.

The following factors may raise a person’s risk of developing anal cancer:

Human papillomavirus (HPV) infection. Research indicates that infection with this virus is a risk factor for anal cancer. HPV is most commonly passed from person to person during sexual activity. There are different types, or strains, of HPV, and some strains are more strongly linked with certain types of cancer. HPV vaccines protect against certain specific strains of the virus.

Age. Most people diagnosed with anal cancer are between age 50 and 80.

Frequent anal irritation. Frequent anal redness, swelling, and soreness may increase the risk of developing anal cancer.

Anal fistula. An anal fistula is an abnormal tunnel between the anal canal and the outer skin of the anus that often drains pus or liquid, which can soil or stain clothing. An anal fistula may irritate the outer tissues or cause discomfort. An anal fistula may increase the risk of developing anal cancer.

Cigarette smoking. Smoking tobacco can cause harm throughout the body, because chemicals from the smoke can enter the bloodstream and affect nearly every organ and tissue in the body. Smokers are about eight times more likely to develop anal cancer than nonsmokers.

Lowered immunity. People with diseases or conditions affecting the immune system—such as HIV or organ transplantation—and people who take immunosuppressive drugs that make the immune system less able to fight disease are more likely to develop anal cancer.


Even though some people who have no risk factors develop anal cancer, there are ways to prevent or reduce your risk of developing anal cancer.

  • Talk with your doctor about HPV vaccination. In 2010, the U.S. Food and Drug Administration (FDA) approved the HPV vaccine Gardasil for prevention of anal cancer in females and males ages nine to 26. Learn more about cancer vaccines.
  • Avoid anal sexual intercourse, which carries an increased risk of HPV and HIV infection.
  • Limit the number of sex partners, because having many partners increases the risk of HPV and HIV infection.
  • Use a condom. However, even though condoms can protect against HIV, they cannot fully protect against HPV.
  • Stop smoking. Learn more about how to quit smoking.

Anal cancer screening. Cancer screening is done to find cancer as early as possible in people who don’t yet have any signs of the disease. Anal cytology is a test being developed that doctors can use for people who don’t have symptoms of anal cancer but do have a high risk of contracting a sexually transmitted disease (STD), such as HPV and HIV. The test is similar to a Pap test, which looks for cervical cancer. The doctor can swab the anal lining and look at the cells on the swab under a microscope to find early cellular changes that might lead to cancer or may diagnose cancer from this swab. Some doctors are advocating the routine use of this test for men who have HIV and who have sex with men and for other people who are at high risk for developing anal cancer.

Research continues to look into what factors cause this type of cancer and what people can do to lower their personal risk. There is no proven way to completely prevent this disease, but the steps above can lower your cancer risk. Talk with your doctor if you have concerns about your personal risk of developing this type of cancer.

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