FRIDAY, March 23 (HealthDay News) -- Anal human papillomavirus
(HPV) infection and precancerous lesions are common among gay and
bisexual men, but most of these cases will not progress to anal
cancer, a new analysis of earlier research shows.
The researchers also found that the rate of progression from
anal lesions to anal cancer among men appears to be much lower than
the rate of progression from cervical lesions to cervical cancer
among women.
Types HPV 16 and HPV 18 cause 80 percent of anal cancers and 70
percent of cervical cancers, according to background information in
the report, published online March 22 in
The Lancet Oncology.
In the study, the researchers analyzed data from 53 previous
studies involving gay and bisexual men and found that most of the
men had anal HPV infection, and 20 percent to 30 percent of them
had precancerous anal lesions.
HIV-positive men were much more likely to be infected with
high-risk HPV types than HIV-negative men (73 percent vs. 37
percent) and were also more likely to have precancerous anal
lesions, the investigators noted.
The progression rate from high-grade anal lesions to anal cancer
was about one in 600 per year for HIV-positive men and about one in
4,000 per year for HIV-negative men. In comparison, the progression
rate from high-grade cervical lesions to cervical cancer is about
one in 80 per year.
Because cervical cancer screening has led to sharp decreases in
cervical cancer cases and deaths, it's been suggested that the same
screening strategies for precancerous anal lesions in gay and
bisexual men could save many lives. However, these findings
indicate it's not that simple, lead author Andrew Grulich, of the
University of New South Wales in Australia, explained in a journal
news release.
"The substantial differences in the natural history of anal HPV infection to those of cervical HPV infection that this review has identified suggests that we cannot simply transfer cervical cancer screening strategies to anal cancer screening," Grulich and colleagues concluded.
"Large, good-quality prospective studies are needed to inform the development of anal cancer screening guidelines for [men who have sex with men]," the authors suggested.
More information
The American Cancer Society has more about
anal cancer.