TUESDAY, Jan. 15, 2002 (HealthDayNews) -- Three decades of blood samples suggest that at least one out of every four gay men living in San Francisco has Kaposi's sarcoma and doesn't know it.
Although it can lie dormant for decades, the rare skin cancer, which is caused by a virus similar to the genital herpes virus, doesn't seem to need AIDS to awaken and wreak havoc, researchers say. The new findings raise the disquieting possibility that the disease could still cause problems for countless gay men, even those who remain HIV-negative throughout their lives."You can't eliminate the virus. Like other herpes viruses, they're basically a lifetime infection," says Dennis Osmond, study co-author and an epidemiology professor at the University of California at San Francisco.
In the years before the AIDS epidemic, Kaposi's sarcoma was mainly a disease of elderly Mediterranean men. It often causes disfiguring skin lesions, and can spread cancer throughout the body in people with weakened immune systems. In advanced cases, the disease can be fatal.
During the AIDS epidemic, purple-colored Kaposi's sarcoma lesions appeared on the faces of many infected gay men. They became a kind of scarlet letter, making a man's AIDS status obvious to the world if he wasn't already gaunt and weary-looking.
"It was a stigmatizing thing to have," Osmond says.
However, the lesions have largely disappeared in gay communities, as AIDS drugs rapidly boosted survival rates.
Osmond and his colleagues obtained blood samples from gay men taken in the late 1970s, 1980s and mid-1990s, and tested them for the Kaposi's sarcoma virus. Their findings appeared in last week's issue of the Journal of the American Medical Association.
The goal of the study was to determine if Kaposi's sarcoma cropped up at the same time as AIDS, the researchers say.
"A lot of people thought that this was a new epidemic in gay men," Osmond explains. "We wanted to find out whether that was true or not."
Of 235 gay men who had blood tests in 1978 and 1979, more than 26 percent were infected with Kaposi's sarcoma, while only about 7 percent were HIV-positive. None of 200 heterosexual men tested was infected.
The researchers found the incidence of Kaposi's sarcoma in the gay male population remained stable over the next two decades, even though many gay men adopted safe-sex practices and HIV levels rose dramatically through the 80s, and then fell off in the 90s.
"Our inference is that it points to oral intercourse as an important route of transmission, rather than (unprotected) anal intercourse," Osmond says. That makes sense because the Kaposi's sarcoma virus is often found in saliva, unlike HIV, which is found in semen, he says.
It's possible infected men will suffer from Kaposi's sarcoma as they become elderly, and their immune systems deteriorate, Osmond says.
The study provides more evidence that safe sex for gay men means more than worrying about AIDS, says Dr. Michael Horberg, a Kaiser Permanente Health Plan doctor who treats AIDS patients in Santa Clara, Calif.
However, he adds, "you can't just live in your life in fear either, and not be willing to express your sexual self."