Study Links Vasectomy to Aggressive Prostate Cancer
But the finding doesn't prove cause-and-effect; urologists call for more research
"There are a whole host of potential unknown reasons why this potentially could be real," he added. "On the other hand, this is a retrospective study -- a backwards-looking study over many, many years, and the increased risk is small. So can this be an error in statistics? There are many papers over the years that don't show a correlation with this."
Dr. Aaron Katz, chairman of urology at Winthrop-University Hospital in Mineola, N.Y., suggested that men who've undergone a vasectomy may simply have their cancers caught more often because they see their doctor more often.
"Several studies have looked at the association between vasectomy and prostate cancer. It is well known that men who have had a vasectomy are more likely to be seen more frequently by urologists in follow-up than men who never had a vasectomy, and will undergo more frequent PSA testing," he said.
The Harvard researchers said they were able to compensate for factors such as more frequent visits to doctors before reaching their conclusions.
Kavoussi added: "The implications of this study, if it becomes dogma, can be quite profound in society. All of a sudden birth control has been pushed entirely onto women. There are potential side effect issues with birth control for women as well."
Support for the study was provided by grants from the U.S. National Cancer Institute, among other sources.