Circumcision helps protect against the transmission of human papillomavirus, indicates US and Ugandan research published in The Lancet today.
The findings are based on the results of two parallel but independent randomised controlled trials of male circumcision, involving HIV negative men and their HIV negative female partners between 2003 and 2006, in Rakai, Uganda.
The men were randomly assigned to undergo circumcision immediately (intervention) or after 24 months (control). Vaginal swabs were taken from the female partners—648 of men from the intervention group, and 597 of men in the control group—at the start of the study, and then 12 and 24 months later to test them for high-risk HPV.
During the course of the trial, 18 men in the control group were circumcised elsewhere, and 31 in the intervention group did not have the procedure.
At 24 months data were available for 544 women in the intervention group and 488 in the control group. Of these, 151 (28%) in the intervention group and 189 (39%) in the control group had high-risk HPV infection, indicating that those women whose partners were not circumcised had a 28% higher risk of becoming infected with HPV.
The numbers of new cases of high risk HPV infection in women was lower in the intervention group than in the control group—20·7 infections vs 26·9 infections per 100 person years, equating to a 23% lower infection rate.
“Circumcision of adolescent and adult men in a rural Ugandan population significantly reduced the prevalence and incidence of both low-risk and high-risk HPV infections and increased clearance of high-risk HPV infections in their female partners,” comment the authors.
And they conclude: “Along with previous trial results in men, these findings indicate that male circumcision should now be accepted as an efficacious intervention for reducing heterosexually acquired high-risk and low-risk HPV infections in men who do not have HIV and in their female partners.”
But they caution: “However, our results indicate that protection is only partial; the promotion of safe sex practices is also important.”
In an accompanying comment, Dr Anna R Giuliano, of the H Lee Moffitt Cancer Center, in Tampa, Florida, and colleagues say that male circumcision is useful in countries without well established cervical screening programmes.
She adds: “Additional interventions to reduce HPV infection, such as provision of vaccines for HPV prevention, will be essential to reduce invasive cervical cancer worldwide.
Male circumcision is associated with slight reductions in high-risk HPV, while licensed HPV vaccines protect with high effectiveness against only a limited number of HPV types. Therefore, the two interventions are likely to have important synergistic effects.”