As fewer boys today are getting circumcised than in the past, a new study adds support to the procedure.
The study, published Monday in the journal Cancer, a journal of the American Cancer Society, found that circumcision reduces the risk of prostate cancer. The authors suggest that circumcision lowers the chance of infections and inflammation that may contribute to cancer.
Many studies have found that sexually transmitted diseases (STDs) including HIV are associated with an increased risk of prostate cancer. Other studies have found that circumcision reduces the risk of infections including STDs. Viruses can slip into the mucosal layers under the foreskin and thrive in the moist environment there, so removing the foreskin appears to lower the risk of infections taking hold. The authors theorized that since circumcision therefore would also reduce the incidence of prostate cancer.
The investigators analyzed data from more than 1,700 men with prostate cancer and a nearly equal number of men without cancer. Approximately 70 percent of all men, who ranged in age from 35 to 74 had been circumcised—the vast majority right after birth. Men who had been circumcised before their first sexual intercourse were 15 percent less likely to develop prostate cancer than those who were not circumcised.
“From these results, we estimate that circumcision may prevent about 10 percent of all prostate cancer cases in the general population,” said Janet L. Stanford, a co-author of the study and research professor at Fred Hutchinson Cancer Research Center in Seattle.
Men who were circumcised after their first intercourse, however, did not benefit from the reduced risk.
In addition, men circumcised prior to having their first sexual encounter had an 18 percent reduced risk for developing a more aggressive form of prostate cancer.
Infections are estimated to be the cause of 17 percent of cancers worldwide. Other cancers that have been linked to infections include cervical, stomach and liver cancers. In fact, one study found that circumcised men are less likely to infect their female partners with the human papillomavirus, or HPV, which is linked to cervical cancer.
Infections are thought to cause a chronic inflammation, which can lead to DNA damage as well as other changes that may help cancers thrive. The study did not find a higher rate of self-reported STDs in men who had prostate cancer, though the authors suggest that the men may not have known they had an STD if they had been a carrier without symptoms.