Getting Snipped and Getting Cancer
You’re done with the kid thing and thinking of getting your wings clipped. What can go wrong early on after a vasectomy is pretty understandable and, fortunately, quite uncommon. But what about later on, say many years afterwards? Anything you should worry about?
I get asked this all the time by patient’s considering vasectomy. And, since it’s a 120-year old procedure in the US, we actually know quite a lot about its long-term consequences. No increased risk of heart disease or stroke, altered male hormone levels, testis cancer, lymphoma, kidney stones, arthritis or overall mortality. And you already know the pain story after vasectomy. Phew! Glad that’s done with.
The one issue that still lingers in the minds of many is whether prostate cancer rates are higher years after vasectomy. Academic careers have been made publishing on this topic. In fact, close to 30 epidemiologic studies of vasectomy and the risk of prostate cancer have been reported over the last 35 years. The research that says “no” to an increased risk of prostate cancer after vasectomy is about as robust as that saying “yes.” Besides this, a clear and plausible biologic reason for any association is completely unknown. So what’s a guy to do?
Don’t Be Biased
Honestly, we may never know the answer to this question. A 40-year prospective trial is the best way to address the issue and put it to sleep, but it ain’t happening. That would mean an intergenerational academic study, which is a very rare bird in medicine. Name a government that is able to fund a study consistently for 4 decades? Similar to the century it used to take to build cathedrals, not many of us can live long enough to see the start and the finish of this kind of study. So, we’re left with short term, cross sectional and retrospective epidemiological studies with all of their inherent “confounders” and a plethora of “biases” of the recall, observer, information, selection and detection types. Add to this a choice among a myriad of different, obscure statistical methods to analyze things, and you can easily get silk from a sow’s ear.
But there is a recent study that I really like. Researchers in Toronto, Canada followed 326,607 men who underwent a vasectomy and compared them to men of similar ages and health status who didn’t get clipped. Yes, that 6-digit number is correct: it consists of all men in Ontario, Canada who had a vasectomy over 20 year period ending in 2012. The average follow-up period was about a decade. They observed that 53% of cancer cases occurred in the vasectomy group and 47% in the non-vasectomy group. Seems like a real difference eh? However, after adjusting for several critically important factors, such “health seeking behavior” (a form of selection bias) and survival bias, thorns in the side of many other studies, this difference melted away. The same was true for rates of high-grade prostate cancer and advanced stage prostate. Poof, gone! No differences.
As a vasectomist, what do I think about all this? At present, I don’t feel vasectomy poses any risk for prostate cancer, so I am unlikely to provide more than a single breath’s worth of commentary with patients who want vasectomies.