Over the years there has been controversy as to the existence of an association between vasectomy and risk for prostate cancer. A new set of data from a large, long-term study, to be presented at the upcoming annual meeting of the American Society of Clinical Oncology, has shown that there is, indeed, such a risk — but it is specific to high-risk prostate cancer.
The paper by Mucci et al. is based on data from 49,432 male participants in the US Health Professionals Follow-up Study, which started in 1986 and followed the participants for 24 years until 2010. All participants were between 40 and 75 years of age at time of enrollment.
Here are the core data from the study:
- 6,398/49,432 men (12.9 percent) were diagnosed with incident cases of prostate cancer.
- 12,371/49,432 men (25.0 percent) met criteria implying that they were “highly screened” for risk of prostate cancer.
- 22 percent of the 49,432 men had had a vasectomy at baseline.
- Of the 6,398 men diagnosed with prostate cancer
- 734 (11.5 percent) were diagnosed with high-grade cancer (Gleason score 8 to 10).
- 813 (12.7 percent) had a lethal form of prostate cancer (i.e., cancer that metastasized or caused their death).
- Among the men who had had a vasectomy at baseline (compared to those who had not), there was
- An increased risk of high-grade prostate cancer (hazard ratio [HR] = 1.23)
- An increased risk of lethal prostate cancer (HR = 1.20)
- The risk of lethal prostate cancer was higher among men who had a vasectomy before age 38 years compared with men receiving vasectomies at older ages.
- Among the men who were “highly screened” for risk of prostate cancer (compared to those who were not), there was
- An increased risk of high-grade prostate cancer (HR ~ 1.20)
- An increased risk of lethal prostate cancer (HR = 1.56).
- The increases in risk associated with vasectomy could not be explained by differences in hormone levels, prevalence of sexually transmitted infections, or cancer treatments.
The authors conclude that, “Data from this study support the hypothesis that vasectomy is associated with a small increased incidence of aggressive prostate cancer defined as high grade cancer and disease causing death or bony metastasis. Differences in diagnostic intensity or confounding bias do not explain this elevated risk.”
Now it should immediately be noted that the authors do not either suggest or imply that there was any evidence of an overall increase in risk for prostate cancer associated with vasectomy. Their findings are exclusively confined to an association between vasectomy and high-risk disease. On the other hand, of course, it is this type of high-risk prostate cancer (the type that kills you or causes metastasis) that men are trying to avoid the most.
As far as The “New” Prostate Cancer InfoLink is aware, this is the first study to suggest that there is an association between vasectomy and high-risk prostate cancer, and it is certainly based upon a large, carefully monitored database.
To put these data into “real numbers” it is telling us that, for every 10,000 men in the USA between the ages of 40 and 75,
- 1,290 will be diagnosed with prostate cancer.
- About 323 of those men may be “highly screened.”
- Of the total of 1,290 patients, about 164 will have a lethal form of the disease.
- Of the 323 men with prostate cancer who were “highly screened,” 41 will have a lethal form of the disease, of whom about 24 had a vasectomy and about 16 didn’t.
- Of the 967 men with prostate cancer who weren’t “highly screened,” 123 will have a lethal form of the disease, of whom about 67 had a vasectomy and about 56 didn’t.
Is this enough to tell a man he shouldn’t have a vasectomy?
That’s a very personal decision and needs to be compared to all the upsides and downsides of not having a vasectomy (perhaps more children; perhaps a spouse dying in childbirth; perhaps a spouse staying on “the pill” for another 10 or 20 years, with all the associated risks; etc.).