Anal cancer's a real pain in the ass. Literally. Once infected, the subject's subjected to slow-growing tumors that invade from the outside in, burrowing deeper into their anal cavities. It may elicit a chuckle from a few of you, but rest assured it's no laughing matter.

The American Cancer Society estimates that in 2007 about 4,650 new cases of anal cancer will be diagnosed in the United States. The number of new anal cancer cases has been increasing for many years.

These numbers continue to rise because of the constant spread of the the human papilloma virus: the same virus can lead to cervical cancer in women.

The disease may not have the largest fatalities in disease history, but they're certainly significant...

Gay activist Peter Tatchell writes in tomorrow's Nursing Standard:

HPV is not as dangerous as HIV. Most strains are non-cancerous. There is, however, no room for complacency. HPV has a long incubation period. With infections rocketing, we risk an exponential rise in anal cancer in 20 to 30 years' time.

Research from the United States suggests that two thirds of HIV-negative gay men, and more than 90 per cent of those who are HIV-positive, are infected with one or more strains of HPV. Some of these strains are linked to the later development of anal cancer.

Thirty five gay men per 100,000 develop anal cancer in the US, which is comparable to the 40 women per 100,000 who developed cervical cancer before the introduction of pap smear tests.

Most HPV research centers on women and scientists have developed a vaccine for the disease, a vaccine many lawmakers may make mandatory. But, as we reported a few weeks ago, a number of gay men have been lining up to get their shot. Unfortunately, the FDA has yet to approve the vaccine for men, leaving gay men out in the cold. Tatchell comments:

A disease affecting women is taken seriously, but the same disease is ignored when it affects gay men. I feel a sense of déjà vu. The official indifference towards anal cancer echoes the neglect of the AIDS epidemic in the early 1980s, when it was confined to the gay community.

And, as in the early 1980s, we're all in this together. While we can't necessarily force the FDA's hand, we can all keep our peepers peeled for the symptoms, which include anal discharge, an itchy bum and sores that don't heal. For more information, click here.

And, of course, watch your asses.