People are talking about the latest news: there may be a connection between having a vasectomy and being at risk for prostate cancer. A new study from the Harvard School of Public Health has raised a red flag in the minds of men who already had vasectomies, and those who are considering them.
Before getting upset, it’s helpful to understand the background, and how the current study was done. Historically, most studies found no connection between vasectomy and a greater chance of prostate cancer. What makes this study different is the number of cases from which data was drawn, and the number of years involved. The researchers had access to files on 49,405 U.S. men who were followed from 1986-2010 (participants in the Health Professionals Follow-Up Study). Their ages ranged from 40-75 at the start of the 24-year study. Over that period, 6,023 of them were diagnosed with PCa (roughly 1 out of 8), and 811 died specifically because of their cancer.
When the data was analyzed, the overall increased risk of developing nonaggressive PCa was 10% for those who had a vasectomy. This is a relative increase, not an absolute risk, we’re talking about. For example, if you live in Omaha and you have a 5% absolute chance of catching the flu in September, I might have a 10% greater chance than you because I work in highly congested New York City. Ten percent of 5 equals 0.5 ; this means I have a 5.5% chance compared to your 5%. There’s almost no difference. My relatively greater chance would be so small that I would not lose sleep over it.
However, what disturbs men about this study was the higher correlation between vasectomy and aggressive, or dangerous, PCa. To quote one news report, “… further analysis found vasectomy was linked to a stronger increased risk of more aggressive forms of prostate cancer: a 19% higher risk for advanced cancer and a 20% higher risk of the lethal form.” Still, even though this sounds high, we have to go back to the idea of absolute vs. relative risk. It’s not as high as it sounds.
Why might vasectomy create a higher disease risk for prostate cancer? One theory is a protein change in semen, but no one really knows.
The bottom line is, if you’ve had a vasectomy and are worried about your risk for prostate cancer, consider getting a baseline 3T multiparametric MRI (3T mpMRI) of the prostate. This type of imaging is noninvasive (at least, the way we do it does not involve any rectal insertion) and is particularly sensitive to the kind of cancers that are worrisome in this study. In the future, you can use imaging to monitor from time to time, knowing that early detection allows the greatest number of treatment choices.
Whatever you do, don’t lose sleep over the relative increase in the odds. They are still very, very small.