Anal Cancer: Risk Factors and Prevention

Approved by the Cancer.Net Editorial Board, 03/2016

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.

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 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. There are vaccines available to protect you from some HPV strains.  

  • 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 diseases or conditions affecting the 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 this type of cancer. Although there is no proven way to completely prevent this disease, you may be able to lower your risk. Talk with your doctor for more information about your personal risk of 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 9 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. 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.

The next section in this guide is Screening. It explains how tests may find cancer before signs or symptoms appear. Or, use the menu to choose another section to continue reading this guide.