Final Verdict on the Link Between Vasectomies and Prostate Cancer Risk

Bimal Bhindi, MD

Bimal Bhindi, MD

In the 1980s and 1990s, reports were published noting that there may be a connection between vasectomies and prostate cancer. A team of researchers from the Mayo Clinic in Rochester, Minnesota and the University of Toronto sought a clearer answer. In examining much of the available evidence, they determined that getting a vasectomy will not increase a man’s risk of developing prostate cancer.

“With the aim of shedding some light onto a debate that is 3 decades old, we conducted a systematic review of the literature and performed a meta-analysis, with a particular attention to study quality, to determine if there is an association between vasectomy and prostate cancer,” the researchers wrote in the study.

Results of more than 40 studies were considered — comprising of more than 12 million participants. After eliminating the studies that were at high risk for bias, the researchers found a weak or nonsignificant association between prostate cancer and vasectomies.

The study examined risk of different types of prostate cancer — high-grade prostate cancer, advanced prostate cancer and fatal prostate cancer – and did not find an increased risk for any of them.

“At most, there is a trivial, non-clinically significant association between vasectomy and prostate cancer risk, that is unlikely to be causal,” Bimal Bhindi, MD, fellow of Urologic Oncology at the Mayo Clinic said in an interview with Oncology Nursing News. “This weak observed association may be due to residual unmeasured confounding in the synthesized studies. Concerns about prostate cancer risk shouldn't prevent men from considering vasectomy as a viable long-term contraceptive option.”

Previous reports suggested that the effects of a vasectomy, such as hormonal imbalances, immunologic effects and cell proliferation changes may play a role in a man’s susceptibility to prostate cancer, however, the authors wrote that the exact mechanisms still have not been proven or understood — even in animal models.

Further, many of the studies in decades prior were observational studies, which are often susceptible to confounding and other limitations.

“Vasectomies are often done by urologists and general practitioners,” Bhindi said. “If men go in to see a GP or urologist, they are more likely to get a PSA test. In turn, if they get screened, they are more likely to have a prostate cancer detected.”

An observational study, therefore, is much more likely to show that more men who get vasectomies get prostate cancer. But does this does not prove that the vasectomy was the cause of the cancer.

Only an estimated 8 to 12% of couples use vasectomy as their form of birth control, but the authors on the study urge men not to fear prostate cancer when making that decision.

“This association is unlikely to be causal and should not preclude the use of vasectomy as a long-term contraceptive option,” the study says.

While Bhindi said that he cannot be sure that the low incidence of vasectomy as a birth control method is due to the notion that it might cause cancer, he did note that it could have been a deterring factor for some men.

“When considering male contraceptive options, hearing that vasectomy might cause cancer can be highly dissuading, and may cause men to overlook several of the benefits of vasectomy as an effective and cost-efficient long-term contraceptive option,” he said.

While many studies often leave room for further research, Bhindi actually said that this report ends the debate, once and for all.

“We feel our study synthesizes the literature in a way that hopefully can bring closure to the debate. In the setting of limited research resources, we in fact advised against further research on this topic, as discussed in our paper,” he said.