Men who have had multiple sexual partners - and particularly those who get gonorrhea - are more likely to also get prostate cancer, say researchers.

For some time, research has known that women who have multiple sexual partners and get certain sexually transmitted diseases (STDs) have a higher risk of getting cervical cancer.

Now a study from the University of Michigan presented in San Francisco at the annual meeting of the American Urological Association, shows that men involved in the same behaviors may have an increased risk of getting prostate cancer, particularly if they get gonorrhea.

“These preliminary findings, among African American men, show that a history of gonorrhea increases their risk of getting prostate cancer,” researcher Aruna V. Sarma, PhD, tells WebMD.

“We don’t know why, but the inflammation involved may make them more susceptible. As we study this issue further, we’ll also look at other infectious sexually transmitted diseases, such as viruses, to see if they play a role, too,” says Sarma who is an epidemiologist and assistant research scientist in epidemiology and urology at the University of Michigan in Ann Arbor, Mich.

She and her team were interested in studying prostate cancer risk factors in black men because they get this cancer more often than white men do, and when they are diagnosed, they tend to have more advanced cancer. Other researchers have speculated that sexual behavior and a history of STDs may be related to prostate cancer risk.

The researchers examined the associations between sexual activity, STDs, and prostate cancer risk. They compared 117 black men with prostate cancer with 719 black men without the disease. The men were aged 40 to 79 years old.

Frequent Sex May Increase Risk

Men who had had more than 20 sexual partners were more than three times more likely to be diagnosed with prostate cancer, compared with men with five or fewer partners, Sarma says. In addition, men who had sex two to three times a month had more than double the prostate cancer risk, compared with men who had not been sexually active in the previous 12 months. Having sex two to three times a week more than tripled prostate cancer risk.

The findings show how important it is for patients to participate actively in their health and give doctors the information they need to screen for prostate cancer risk, Isaac D. Powell, MD, tells WebMD. “I tell patients that they need to take charge of their health.” Powell, who was not involved in the current study, is a professor of urology at the Karmanos Cancer Institute of Wayne State University in Detroit.

By the same token, patients need to be willing to share such information with their doctors, even if cultural barriers make such disclosures awkward. “There’s growing evidence that prostatitis and inflammation can be risk factors for prostate cancer, and so the reason for the physicians asking such questions is sound,” he says.