Men who are circumcised may have a lower risk of developing prostate cancer, a new study finds.

Researchers at the Fred Hutchinson Cancer Research Center in Seattle surveyed 1,754 men with prostate cancer, and 1,645 similar men who did not have the disease.

They found that those who had been circumcised before they first had sexual intercourse were 15 percent less likely to have prostate cancer.

“These data suggest a biologically plausible mechanism through which circumcision may decrease the risk of prostate cancer,” said study researcher Dr. Jonathan Wright, an assistant professor of urology at the University of Washington School of Medicine. He noted that the study was observational; it did not show a cause-and-effect link.

Still, the reason for the findings might be that men who are uncircumcised are more likely to contract sexually transmitted infections. The inflammation caused by those infections may in turn be involved in the development of prostate cancer, the researchers said.

The study appears today (March 12) in the journal Cancer.

Circumcision & cancer

Because the results were based on men with prostate cancer at a single point in time, and not the result of following patients forward in time, from circumcision through developing prostate cancer, other experts expressed concerns the results might be skewed for unknown reasons.

“It certainly is an interesting and thought-provoking report,” said Dr. Durado Brooks, director of prostate and colorectal cancers for the American Cancer Society, which publishes the journal.

But the findings would need to be replicated in other groups of people, Brooks said.

“I don't believe it's anything that will alter clinical practice, either for adults or children,” Brooks said.

For parents wanting to know the benefits from circumcision, the possibility of lowering the risk of infections “would be a more convincing and better documented concern…than the possibility of prostate cancer 50 years down the line,” he told MyHealthNewsDaily.

Medical organizations have noted small benefits potentially arising from circumcision, but have not advocated for circumcision as a matter of routine, largely because the procedure can have complications.

“At the end of the day, we feel there's risks and benefits, and it's up to the parents to decide what is in the best interests of their child,” said Dr. Andrew Freedman, a pediatric urologist and a member of the circumcision task force at the American Academy of Pediatrics.

The AAP is now revisiting its position on circumcision, which was last reaffirmed in 2005. A new statement is due to be released this year.

Circumcision in adulthood

One concern Freedman expressed about the new study was that the highest rates of prostate cancer were found in men who were circumcised as adults.

While this was the smallest group of men in the study, and therefore most likely to have the results skewed by chance, he said that the inclusion of these men with others who were not circumcised may have made the benefit of circumcision seem larger than it actually is.

Men getting circumcised later in life might be doing so because of increased infections, Freedman said.

“Circumcision after sexual debut means the male may have already acquired a STI, and might already have inflammatory damage to the penis,” said Brian Morris, a professor at the University of Sydney.

Morris said he is more in favor of circumcision than most in the mainstream medical community, having published research that indicates cost savings from circumcision in infancy, in the form of reduced infections later in life.

Noting a higher rate of urinary tract infections among uncircumcised men, Morris said, “I'd like to see more research done to see whether there is a connection between these and prostate cancer.”

Pass it on: Men who are circumcised before their first sexual intercourse may have a decreased risk of prostate cancer.

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Correction: This article was updated on March 14 to state that the research was done at the Fred Hutchinson Cancer Research Center. The original version incorrectly said it was done at the University of Washington.