Gay and bisexual men, especially those with HIV, are at significantly higher risk for anal cancer than the general population.

Statistics show that the rate for anal cancer in gay and bisexual men (without HIV) is about the same as the rates of cervical cancer in women before pap smears became routine. Routine pap smears have decreased the incidence of cervical cancer from 30-40 per 100,000 women to approximately 8 per 100,000.

The incidence of anal cancer among gay and bisexual men who are long-term HIV survivors has increased greatly. This is probably due in part to the fact that men are now surviving longer with recent effective HIV treatments, and are thus experiencing rising rates of other, previously uncommon cancers.

Anal cancer and cervical cancer are caused by the same viruses-"high risk" varieties of the human papillomavirus (HPV). There are many different strains of HPV-most of which cause harmless warts in various places on the body (e.g., feet, hands, genitals). A few high risk strains of HPV can lead to anal cancer or cervical cancer if not caught and treated early. Most often, though, infection even with those "high risk" strains of HPV doesn't result in cancer.

Men become infected with anal HPV through receptive anal intercourse. One study estimates that approximately 95 percent of gay men with HIV and 65 percent of gay men without HIV have HPV in their anal canals or the surrounding skin.

Recommendations for gay and bisexual men

Recommendations for routine testing of gay and bisexual men are as yet uncertain, as this is an area of ongoing and active research, and no standards have yet been adopted.

What is an anal pap test and how are lesions and warts treated?

Warts are mostly caused by "low risk" strains of HPV that do not lead to cancer. However, they often need to be treated. Treatment usually consists of freezing them with liquid nitrogen, or the use of surgery or cautery.

Anal cancer is caused by "high risk" strains of HPV that can only be detected with an anal Pap test. In this procedure, a health care provider passes a swab into the rectum and collects cells. These cells are then put on a slide that is examined by an experienced pathologist in a lab under a microscope.

It takes many years for pre-cancerous anal lesions to develop into cancer. If the cells show changes of the kind that could lead to cancer, the patient should undergo a thorough rectal exam by an experienced proctologist. If the problem is caught early, before a cancer develops, it can easily be treated in a doctor's office.

Treatment for these anal lesions varies from simple in-office procedures, such as freezing the cells or applying a topical cream, to surgery or biopsy, if the lesions are widespread. Treatment is very effective in removing lesions, but they may come back in the same or other areas, so it is important to continue to have regular screenings. Persons with advanced tumors will often need other treatment.