Is Vasectomy associated with an increased risk of Prostate Cancer?

A 2014 report from the Journal of Clinical Oncology by Mucci et al states there might be a very small increase in risk over all and a larger increased risk for advanced or lethal prostate cancer. The study from Harvard School of Public Health in Boston, MA, examined the correlation between vasectomy and prostate cancer in over 6000 US men with prostate cancer in the “Health Professionals Follow Up Study”. Men who had had a vasectomy had a very slight increase in relative risk of 1.1 (10% higher) and those with aggressive disease had a slightly higher risk of 1.2.

Are those numbers cause for concern? Here are some reasons to think before reacting.

1. Association does not imply cause effect. A common example is the correlation between ice cream sales and murders. Increase in murders have been noted to correlate with increases in ice cream sales, but few would suggest that icecream causes murder.
2. There was no significant link between vasectomy and risk of low-grade prostate cancer.
3. For a subgroup of men who were having regular PSA tests, the increased risk was 56%. The authors are careful not to suggest that screening for prostate cancer increases the risk of getting prostate cancer.
4. Relative risk is not absolute risk. An increase in relative risk in this population studies follows the following : In the study 16 men per 1000 in the study developed prostate cancer for an incidence of 1.6%. An inreased risk of 10% would change that number to 1.76% The authors concede that although the increased risk was found to be statistically significant, its effect is a relatively small increase in the absolute risk of developing prostate cancer.

The authors actually get it right and most everyone else, particularly in the media, are getting it wrong. In their data set, there was an “association” of the two populations: Men with vasectomy and Men with prostate cancer. However, any suggestion that one causes the other is a myth.

Other myths about vasectomy include:

1. It lowers your testosterone: Untrue. Reports show that testosterone is unaffected and or may actually slightly increase after vasectomy.
2. It decreases your enjoyment of sex: untrue; patients attest to more enjoyment of their sex life without the burden of needing to worry about contraception.
3. Vasectomies cannot be reversed: Untrue. Vasectomy reversal can be readily accomplished in the majority of men with vasectomies. Best results are achieved with a microsurgical approach. Vasectomy reversal is a significant part of my practice.

Furthermore, there is no plausible proposed biological mechanism by which a vasectomy might increase the risk of cancer.

Be wary of drawing conclusions from associations. A recent study from the UK published in the Journal of Men’s Health states that cycling is associated with an increased risk of prostate cancer and that the more cycling that is done, the higher the risk. The study fails to explain why countries that have heavy bicycle use such as China do not have a much higher incidence of prostate cancer. Could there be something else behind the association in their data set?

Finally, several other studies have not found any correlation between vasectomy and prostate cancer. In a 1999 study by Michael Brawer et al in Cancer, Epidemiology, Biomarkers and prevention published, a study of a more select population of over 700 patients with prostate cancer who were questioned with respect to a variety of possible associations. In addition to PSA, Patients were also questioned regarding demographics, reproductive history, stature, family history, smoking, alcohol consumption, sexual history and occupation. Finding revealed there was no statistically significant difference in the incidence of prostate cancer in vasectomy versus non vasectomy groups.

Therefore, at this point in time, I am comfortable stating that there is insufficient evidence to show concern of causing an increased risk of getting prostate cancer by having a vasectomy, but that there is testimony from many of my patients that they have less worry and more enjoyment from life after their birth control was put on autopilot.