A new analysis led by researchers at Fred Hutchinson Cancer Research Center has found that circumcision（包皮环割术） before a male's first sexual intercourse may help protect against prostate cancer. Published early online in Cancer, a peer-reviewed journal of the American Cancer Society, the study suggests that circumcision can hinder infection and inflammation that may lead to this malignancy（恶性肿瘤） . Infections are known to cause cancer, and research suggests that sexually transmitted infections may contribute to the development of prostate cancer. Also, certain sexually transmitted infections can be prevented by circumcision. Therefore, it stands to reason that circumcision should protect against the development of some cases of prostate cancer. This is what lead author Jonathan L. Wright, MD, an affiliate investigator in the Hutchinson Center's Public Health Sciences Division, and his colleagues set out to test.

For their study, the investigators analyzed information from 3,399 men (1,754 with prostate cancer and 1,645 without). Men who had been circumcised before their first sexual intercourse were 15 percent less likely to develop prostate cancer than uncircumcised men. This reduced risk applied for both less aggressive and more aggressive cancers. (Specifically, men circumcised before their first sexual intercourse had a 12 percent reduced risk for developing less aggressive prostate cancer and an 18 percent reduced risk for developing more aggressive prostate cancer.)

Sexually transmitted infections may lead to prostate cancer by causing chronic inflammation that creates a hospitable environment for cancer cells. Other mechanisms may also be involved. Circumcision may protect against sexually transmitted infections, and therefore prostate cancer, by toughening the inner foreskin and by getting rid of the moist（潮湿的） space under the foreskin that may help pathogens survive.

"These data are in line with an infectious/inflammatory pathway which may be involved in the risk of prostate cancer in some men," said Dr. Wright, who is also an assistant professor of urology at the University of Washington School of Medicine. "Although observational only, these data suggest a biologically plausible（貌似可信的） mechanism through which circumcision may decrease the risk of prostate cancer. Future research of this relationship is warranted," he added.