Circumcising men may significantly reduce the rate of cervical cancer in women by decreasing the spread of a sexually transmitted virus that causes nearly all cases of cervical cancer, researchers are reporting.
A study being published today in The New England Journal of Medicine provides important scientific evidence for a link that scientists have long suspected.
The new findings are based on 1,913 couples in five countries, including 977 couples in which the woman had cervical cancer and 936 couples without cancer. Researchers found that circumcision made a difference if the man had had six or more sex partners, which made him more likely to have contracted the cancer-causing human papilloma virus, or H.P.V. In those couples, the risk of cervical cancer was more than double if the man was not circumcised.
The findings may not apply to couples in which the man has had fewer than six sex partners, because he is less likely to be carrying H.P.V.
The researchers say uncircumcised men may be more likely than others to contract H.P.V. because the lining of the foreskin is especially vulnerable to the virus. Their study, which used DNA testing to look for penile H.P.V. infection in the men, found that uncircumcised men were about three times as likely as circumcised men to be infected.
Of the 1,913 men in the study, 1,215 had had six or more partners and 1,543 were not circumcised.
The researchers, led by Dr. Xavier Castellsague of the Llobregat Hospital in Barcelona, used data from seven studies in Brazil, Spain, Thailand, Colombia and the Philippines.
H.P.V. is common, and 20 million Americans are thought to be infected. The virus has about 100 strains, including 30 that are sexually transmitted. Not all the strains can cause cervical cancer, and even when women contract a strain that does, most eliminate the virus from their bodies without developing cancer. Some doctors recommend condoms to prevent H.P.V., but others say they may not work as well for this virus as they do for other infections.
In the United States, there are about 13,000 cases of cervical cancer a year and 4,100 deaths. Doctors often say it is a disease that no woman should die of. It is easily cured if detected early by a Pap test, and the death rate in North America has declined in the past decade.
Worldwide, there are about 466,000 cases of cervical cancer a year. Each year, 231,000 women die of the disease, mostly in developing countries, and in some of those countries the death rate is not declining.
An editorial in The New England Journal of Medicine noted that worldwide, 25 percent of all men are circumcised. It also said that in the United States in the 1970's about 80 percent of all newborn boys were circumcised, but that the rate had dropped since then because medical groups like the American Academy of Pediatrics said the procedure did not have enough benefits to recommend its routine use.
Dr. Dimitrios Trichopoulos, a professor of cancer prevention and epidemiology at the Harvard School of Public Health and a coauthor of the editorial, said the new study provided a medical argument for circumcision. Dr. Trichopoulos said that on the strength of the study, if he had a newborn son he would have him circumcised. If the global circumcision rate could be increased to about 75 percent, he said, it could lead to a 23 percent to 43 percent drop in the incidence of cervical cancer.
But Dr. Trichopoulos said he doubted that such a rate would ever be reached, because of costs and other factors. "This is an area where you have political and religious sensitivities," he said.
Dr. Carol L. Brown, a gynecologic oncologist and expert on cervical cancer at Memorial Sloan-Kettering Cancer Center in Manhattan, said that a study like the one being reported today should be done in this country before doctors considered making recommendations about circumcision in the United States.
"This data is good, but we have different populations," Dr. Brown said, adding that H.P.V. strains may differ, that circumcision rates are relatively high and that it cannot be assumed that the findings would be the same in the United States.