In July 2014, a research team at the Harvard School of Public Health exhumed the debate about a potential relationship between vasectomy and prostate cancer. Their research team’s results made it into newspapers around the world, including the NY Times and The Guardian.
I had a vasectomy about 35 years ago. You’ll see below why I am not worried.
Epidemiology is the science of identifying the causes of disease. Epidemiologic studies showed contaminated drinking water caused cholera epidemics and that smoking caused lung cancer. These results were scientifically sound. But now, with publish-or-perish pressures on academic physicians and the concept of multifactorial causation, many researchers are submitting poorly conducted studies or poorly interpreted results, i.e. studies with weak associations that are claimed to show evidence of cause and effect. And these studies generate scare stories in the media.
Mark Twain once said, “A lie can travel halfway around the world while the truth is putting on its shoes.” Unfortunately, the news media like a good scare story. The prostate cancer scare traveled to the NY Times and The Guardian within days of the Harvard research team’s publication. The media’s pace is frantic compared to academia—it took six months for our rebuttal to go from peer review to publication. A letter by myself and colleagues pointing out weaknesses in the study was published online on January 20.
Fortunately, some health authorities—UK National Health Service, for instance—immediately issued press releases to counteract the scary headlines. The UK folks pointed out that, “This type of study … cannot show that vasectomies cause prostate cancer, as there could have been differences in the men that opted for vasectomy that the researchers did not adjust for. Overall… men should not be overly concerned by these reports.”
Evidence from various studies of this topic has been mixed over the years, but the debate had largely vanished from the news as more evidence had accumulated showing no association between vasectomy and prostate cancer. Perhaps the most important study showing no association was one from New Zealand, the country with the highest vasectomy prevalence in the world—57% in men 40 to 49 years of age—and a country that has a national cancer registry. What was the verdict from New Zealand? No association between vasectomy and prostate cancer.
