March 12, 2012

Prostate Cancer Risk Declines With Circumcision

A new study published Monday in the journal Cancer finds that circumcised men may have a slightly lower risk of developing prostate cancer than those who still have their foreskin, reports Reuters´ Frederik Joelving. The World Health Organization (WHO) has long recommended the controversial procedure based on research showing it lowers heterosexual men´s risk of contracting the HIV virus.

Scientists reported last year that wives and girlfriends of circumcised men had lower rates of infection with human papillomavirus (HPV), which in rare cases may lead to cervical and other cancers. And last week, researchers reported that African men who were circumcised were less likely to be infected with a particular herpes virus.

“The new work jibes with those findings, but it falls short of actually proving that removing a boy´s foreskin will cut his future cancer risk,” said lead researcher Dr. Jonathan L. Wright, of the Fred Hutchinson Cancer Research Center in Seattle.

“I would not go out and advocate for widespread circumcision to prevent prostate cancer,” Wright continued, ”we see an association, but it doesn´t prove causality.”

The Royal Dutch Medical Association calls it a, “painful and harmful ritual,” and California Governor Jerry Brown struck down an effort to ban circumcision in San Francisco arguing it would infringe on religious freedom.

For their study, Wright and his colleagues compared two groups of more than 1,600 men who had answered questions about their medical history, sex life and whether or not they were circumcised. Half of the men had prostate cancer, while the other half didn´t.

In the cancer-ridden group, 69 percent of the men had been circumcised, while that was the case for 72 percent of the comparison group, suggesting a small protective effect of the practice.

Even after accounting for a host of other factors -- such as age, race and whether or not the men had been screened for prostate cancer -- those without a foreskin still had a 15 percent lower risk of the disease.

Only men who´d been circumcised before they became sexually active were at lower risk. The foreskin is prone to tiny tears during sex, which may help bacteria and viruses enter the bloodstream.

Some viruses, Wright explains, can trigger cancer when they get incorporated into human DNA. Another possibility is that sexually transmitted microorganisms could lead to cancer by causing chronic inflammation. That might help explain the link found by several research groups between prostate cancer and various types of sexually transmitted infection.

One in six American men will get prostate cancer during his lifetime, although only a minority of them will die from the disease.

While some doctors advocate screening for the disease, the government-backed US Preventive Services Task Force has released a draft proposal recommending against it. Wright said his study -- the largest and most comprehensive of its kind so far -- was focused on shedding light on cancer development, rather than prevention.

“We need to do more work to try to understand this,” he said. “Our overarching goal is to understand how cancer develops in people.”


On the Net: