NEW YORK (Reuters Health) - While uncircumcised men don't seem to be
at higher risk of acquiring human papillomavirus (HPV), it takes them
longer to clear the virus from their bodies, new research shows. Because
HPV causes genital warts and certain cancers, the finding, say
researchers, could help explain why uncircumcised men have a higher risk
of such penile cancers.
It could also play a role in how likely their partners are to
develop infections.
"Our study demonstrates that the apparent protective influence of
circumcision against genital HPV infection may not involve a reduction
in new infections but rather the enhanced ability to resolve existing
HPV infections," Dr. Brenda Y. Hernandez of the Cancer Research Center
of Hawaii in Honolulu and her colleagues write.
But why this might be, and whether circumcision would be a good
way to help prevent the spread of HPV-related disease, remains unclear,
according to the researchers.
Some HPV strains cause cervical cancer in women, and are the
targets of the vaccines Cervarix and Gardasil. Some strains may also be
associated with penile cancer in men.
There's evidence that circumcision lowers a man's likelihood of
developing cancer of the penis and contracting HPV infection, as well as
HIV infection, in some populations. Because partners of uncircumcised
men face a higher risk of cervical cancer, it's possible that
circumcision could affect the spread of the virus as well, Hernandez and
her team note.
The researchers had previously found that circumcised men were
less likely than their uncircumcised peers to be infected with HPV at a
given point in time. To determine if circumcision might influence a
man's risk of acquiring HPV infection, as well as how readily he could
clear the virus from his body, the researchers followed 357 men for an
average of about 14 months. Every two months, the men, 290 of whom were
circumcised, underwent HPV testing.
During the study, the researchers identified 536 different HPV
infections, with no difference in risk between the circumcised and
uncircumcised men. However, the researchers did find that HPV infections
of the head, or glans, of the penis lasted 154 days, on average, in the
uncircumcised men, compared to 91 days in the men who were circumcised.
The increased duration was seen for both cancer-associated and
non-cancer-associated HPV strains.
Cancer of the penis most commonly develops in the glans,
Hernandez and her team point out, and the fact that infection with
cancer-related strains lasted longer in uncircumcised men "has clinical
significance."
It's possible, they add, "that transmission of HPV to sex
partners is more efficient among circumcised men because of the greater
duration of their infection." However, they add, "whether circumcision
is an effective means of facilitating HPV clearance has yet to be
demonstrated."
SOURCE: here
Journal of Infectious Diseases, May 1, 2010.