Anal Cancer: Risk Factors and Prevention

Approved by the Cancer.Net Editorial Board, 09/2022

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

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. 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 shows that infection with this virus is a risk factor for anal cancer. Sexual activity with someone who has HPV is the most common way someone gets HPV. There are different types of HPV, called strains. Research links some HPV strains more strongly with certain types of cancers. HPV vaccines can prevent people from developing certain cancers. Learn more about HPV and cancer.

  • 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. The tunnel 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. Chemicals from the smoke can enter the bloodstream and affect nearly every organ and tissue in the body. Smokers are about 8 times more likely to develop anal cancer than nonsmokers.

  • Lowered immunity. People with a disease or condition affecting their body's immune system—such as human immunodeficiency (HIV) or organ transplantation—are more likely to develop anal cancer. People who take immunosuppressive drugs that make the immune system less able to fight disease are also more likely to develop anal cancer.


Different factors cause different types of cancer. Researchers continue to look into what factors cause anal cancer, including ways to prevent it. Although there is no proven way to completely prevent anal cancer, you may be able to lower your risk. Talk with your health care team for more information about your personal risk of cancer.

  • Talk with your doctor about HPV vaccination. The HPV vaccine Gardasil is approved by the U.S. Food and Drug Administration (FDA) for prevention of anal cancer. Learn more about cancer vaccines.

  • Anal sexual intercourse can increase your risk of developing anal cancer because it increases your risk of HPV and HIV infection. Regular STD testing can help prevent exposures and can help you know what you might have been exposed to in the past. This can help you and your health care provider know if screening for anal cancer is appropriate for you (see Screening).

  • Limit the number of sex partners. Having many partners increases the risk of HPV and HIV infection.

  • Use a condom during sexual activity. However, even though condoms can protect against HIV, they cannot fully protect against HPV.

  • Stop smoking. Learn more about how to quit smoking.

The next section in this guide is Screening. It explains how tests may find cancer before signs or symptoms appear. Use the menu to choose a different section in this guide.