and Medicine for Seniors
Vasectomy Appears to Increase Risk of Aggressive,
Lethal Prostate Cancer
Men who had regular PSA screening had a increased
risk of 56% for lethal prostate cancer; effect stronger among men who
had a vasectomy at younger age.
9, 2014 – The largest study to examine the link between vasectomy and
prostate cancer has found that men who had this birth control procedure
have a small increase in their risk of prostate cancer but a stronger
risk for advanced or lethal cases of this cancer.
The Harvard School of Public Health (HSPH)
researchers found that the association remained even among men who
received regular PSA screening, suggesting the increased risk of lethal
cancer cannot be explained by diagnostic bias.
The results showed a 10% increased risk of prostate
cancer overall in men who had a vasectomy. Vasectomy was not
significantly associated with risk of low-grade. However, vasectomy was
associated with an increased risk of 20% for advanced prostate cancer
and 19% for a lethal case.
Among men who received regular PSA screening, the
relative increase in risk of lethal prostate cancer was 56%. The effect
appeared to be stronger among men who had a vasectomy at a younger age.
The study appeared online July 7, 2014 in
Journal of Clinical Oncology.
"This study follows our initial publication on
vasectomy and prostate cancer in 1993, with 19 additional years of
follow-up and tenfold greater number of cases. The results support the
hypothesis that vasectomy is associated with an increased risk of
advanced or lethal prostate cancer," said co-author Lorelei Mucci,
associate professor of epidemiology at HSPH.
Vasectomy is a common form of contraception in the
U.S., with about 15% of men having the procedure. Prostate cancer is the
second-leading cause of cancer death among U.S. men, so identifying risk
factors for lethal prostate cancer is important for public health.
The researchers analyzed data from 49,405 U.S. men
in the Health Professionals Follow-up Study, who were followed for up to
24 years from 1986 to 2010. During that time, 6,023 cases of prostate
cancer were diagnosed, including 811 lethal cases. One in four of the
men in this study reported having a vasectomy.
Prior work on this topic raised concerns that the
positive associations could be linked to bias. However, in the present
study, the researchers had access to diverse information and could rule
out potential biases, including that men who have vasectomies may seek
more medical care in general, that they may have a higher rates of PSA
screening, or that the association was due possible confounding by
sexually transmitted infections.
In this study, 16 in 1,000 men developed lethal
prostate cancer during 24 years of follow-up. Although the relative
increase in the risk associated with vasectomy was significant, this
translates to a relatively small increase in absolute difference in the
risk of lethal prostate cancer, say the researchers. "The decision to
opt for a vasectomy as a form of birth control is a highly personal one
and a man should discuss the risks and benefits with his physician,"
said co-author Kathryn Wilson, research associate in the Department of
Epidemiology at HSPH.
Support for the study was provided by the National
Cancer Institute/National Institutes of Health.