Jun 16 2009
In a study published in The New England Journal of Medicine, gay and bisexual men were found to have a significantly higher risk for developing anal cancer, over thirty-five times greater than the general population. HIV-positive men were estimated to be eighty times more likely to get it. Although anal cancer accounts for less than 5 percent of all digestive and intestinal tract cancers, the rates have increased 160 percent over a thirty- year period. Gay African-American men have the sharpest increase and the lowest survival rates. Interestingly, anal cancer in gay men is as common as cervical cancer was in women before the use of the Pap smear, the test that screens for precancerous lesions on the cervix. Both types of cancer are caused by the human papillomavirus (HPV), which also causes anal and genital warts. HPV is one of the most common STDs in the world. Fortunately, anal cancer is highly preventable and treatable if caught in time.
There are more then one hundred different subtypes of HPV, and some are the source of common warts as seen on the hands and feet. HPV affects approximately 65 percent of HIV-negative gay men, and nearly 95 percent of HIV-positive gay men carry HPV in their anal canals. Most do not even know they have it. Subtypes 6 and 11 cause 90 percent of genital warts, while subtypes 16 and 18 are far more dangerous because of their precancerous potential.
The lining of the anal canal, once infected with HPV, can reproduce uncontrollably if left untreated. In most cases, the immune system clears the infection naturally, but in a small number of cases, usually over many years, HPV can cause changes in the cells of the anus and rectum that can lead to cancer. The Pap smear is something that should be offered to all gay men. In March 2007, the New York State Department of Health AIDS Institute, in collaboration with the Johns Hopkins Division of Infectious Diseases, issued the following recommendation concerning anal Pap smear.
Clinicians should perform anal Pap tests at baseline and annually in the following populations:
1. Men who have sex with men
2. Any patient with a history of anal or genital warts
Clinicians should refer patients with abnormal anal Pap test findings for high- resolution anoscopy and/or examination with biopsy. Like cervical cancer, invasive squamous cell cancers of the anal canal are associated with certain types of HPV infection, most notably, HPV-16 and HPV- 18. Although this is a new practice that may not be routinely available, screening for cellular dysplasia is recommended, particularly in persons at high risk for infection with papilloma viruses.
There are various ways to treat genital and anal warts depending on the size and location. Topical medications, like podofilox & Imiquimod (Aldara) can sometimes be used. Cryotherapy, electrodesiccation, application of trichloroacetic acid or bichloroacetic acid and interferon injections are just some of the many treatment options that should be discussed with your physician.
The anal Pap smear is a simple test that is performed by your doctor in his office. It involves swabbing the anus with a Dacron swab, which looks like a long Q-Tip. The swab is then smeared on slides and sent to the pathologist. This test is so important because there are many different types of HPV. The most common are types 6, 11, 16, and 18. Certain subtypes, specifically 16 and 18, are considered precancerous. As a patient, you should report any cauliflower-like lesions that develop on your skin because HPV can show up on your penis, anus, and even your tongue.
In 2006, Merck & Co delivered the first vaccine for HPV called Gardasil. It is a quadrivalent vaccine, which means it works on HPV subtypes 6, 11, 16, and 18, and it is given in three separate injections over six months. Currently, the vaccine is indicated only for women, but the majority of gay health- care providers are urging their gay male patients to consider this vaccine, especially those men who are HIV positive or have a history of HPV. At this time the vaccine is not covered by insurance and would have to be paid for out of pocket. Presently, Merck is studying this vaccine in 4,000 young men, including those who engage in sex with other men, and the National Institutes of Health (NIH) is evaluating the response to Merck’s vaccine in preteen HIV- positive boys and girls.