Dr. David Samadi is the chairman of urology and chief of robotic surgery at Lenox Hill Hospital in New York City and is a board-certified urologist and oncologist specializing in the diagnosis and treatment of urologic diseases, kidney cancer, bladder cancer and prostate cancer. Samadi also specializes in many advanced, minimally invasive treatments for prostate cancer; is one of the few urologic surgeons in the United States trained in oncology, open-, laparoscopic- and robotic-surgery; and was the first surgeon in the nation to successfully perform a robotic surgery redo. He contributed this article to Live Science's Expert Voices: Op-Ed & Insights.
I'm writing a new "prescription" for my patients these days: Have more sex with your partner. Evidence continues to accumulate that suggests sexual activity lowers men's prostate cancer risk.
New research supporting this notion is now attracting a lot of attention: Analyzing questionnaires from more than 3,200 men, Canadian scientists found that men who have sex with more than 20 women — rather than just one partner over a lifetime — is linked with a 28 percent drop in the odds of one day being diagnosed with prostate cancer.
The study — the first suggesting the number of female partners is inversely linked to prostate cancer risk — was published online on Sept. 29 in the journal Cancer Epidemiology. The research also suggested that men who said they'd never had sexual intercourse were nearly twice as likely to be diagnosed with prostate cancer as those who weren't virgins. Men who had slept with more than 20 women were not only markedly less likely to get any type of prostate cancer, but experienced a 19 percent reduction in diagnoses with aggressive types of prostate cancer. Of the men surveyed, about half had been diagnosed with prostate cancer between September 2005 and August 2009, while the other half were part of a healthy control group.
Don't just start sleeping around
But don't immediately jump to the conclusion that research now justifies having sex with a broader range of partners — which isn't the same as having lots of sex with a committed partner. To my mind, the study results simply reinforce studies from 2003 and 2004 suggesting that frequent ejaculation, whether with one partner or many, can protect against prostate cancer .
While physicians already know that certain factors influence men's prostate cancer risk — such as family history, race and diet — science is also increasingly blaming inflammation in cancer development. A study published earlier this year strongly indicated that when men don't ejaculate often, inflammatory cells can gather in the seminal vesicles adjacent to the prostate gland, which over time might lead to cancer.
From prior research, it appears that ejaculation frequency — not the number of sexual partners — is the key factor in cutting prostate cancer risk. The novel new research from Canada doesn't specifically address this theory, and it doesn't prove that having more sex or more partners prevents prostate malignancies. It simply establishes a robust association that needs to be validated in additional future studies.
An unexpected prescription
As a urologist, I've always told my patients that having sex two to three times a week is a worthwhile goal. Scientists have long known that regular sexual activity offers meaningful health benefits. Not only is sex proven to reduce stress and promote clearer thinking, but it cuts the amount of inflammation circulating in the body.
The new research is another good excuse for sex. It's also timely, coming in "Movember" — an annual event encouraging men to grow mustaches in November to raise awareness of men's health issues, particularly prostate cancer. As part of the #SamadiChallenge, I'm urging people to help nudge the men in their lives to learn about prostate cancer risk factors and undergo cancer-detecting PSA (prostate-specific antigen) blood tests .
Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google+. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.
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