The papers recently reported that having a vasectomy can increase a man’s risk of developing aggressive prostate cancer. We take a look at the research behind the headline.
The new research, published in the Journal of Clinical Oncology, was undertaken at Harvard Medical School and was a 24 year follow-up study of 49,405 men in the United States aged between 40 and 75 from 1986 to 2010.
Of these, 12,321 men (25 per cent) had a vasectomy. A vasectomy is a minor operation, where the tubes that carry sperm from a man's testicles to the penis are cut, blocked or sealed, usually as a form of contraception.
In total 12.4 per cent of men in the study who’d had a vasectomy developed prostate cancer, compared to 12.1 per cent of men who hadn’t.
They found no link between having a vasectomy and developing non-aggressive, localised prostate cancer. But they did find that there was a 22 per cent increased relative risk of developing aggressive prostate cancer for men who’d had a vasectomy compared to men who hadn’t.
Although this sounds quite a lot when you talk in terms of relative risk (comparing two groups), when you turn it into actual numbers, it’s really pretty small. It translates to 17 out of 1,000 men who didn’t have a vasectomy developing aggressive prostate cancer, compared to 19 out of 1,000 men developing agressive prostate cancer who did have a vasectomy.
The other important thing about this research is that although it shows us a link between having a vasectomy and having aggressive prostate cancer, it can’t and doesn’t tell us that one causes the other, or why the link is there.
We’d need a different type of research to understand that. Deciding whether or not to have a vasectomy is highly personal, and should be discussed with a GP. We don’t think men need to be too concerned about these results at this stage.