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Previous research has been mixed about the risk of prostate cancer
associated with vasectomy, a common form of long-term birth control
that involves snipping or blocking tubes that transport sperm out of
the testicles.
“Our study provides some reassurance that having a vasectomy is
unlikely to meaningfully increase risk of developing any type of
prostate cancer, including fatal prostate cancer,” said lead study
author Eric Jacobs, a researcher at the American Cancer Society in
Atlanta.
Two things that do make prostate cancer more likely are smoking and
obesity, Jacobs said by email.
“Men who want to lower their risk of fatal prostate cancer should
focus on maintaining a healthy weight and, if they smoke, quitting
smoking,” Jacobs said.
Prostate cancer is the second most common type of malignancy among
men in the U.S., behind melanoma.
While vasectomy isn’t the primary form of birth control for most
couples, about 5 percent of women of reproductive age in the U.S.
say this is the method they use to prevent pregnancy, according to
the Centers for Disease Control and Prevention.
Men who undergo this sterilization procedure often worry about
whether it will negatively impact their sex life or fail to prevent
pregnancy.
Concerns about a cancer risk spiked after a large 2014 study linked
vasectomies to a 10 percent greater risk of developing prostate
tumors, as well as a 20 percent higher risk of fatal prostate
cancer, Jacobs and colleagues note in the Journal of Clinical
Oncology.
But the overall risk of prostate cancer is still quite low, said
Jennifer Rider, a public health researcher at Boston University and
Harvard University who was an author on the 2014 study.
“Even a 20 percent increase in the risk of lethal disease – if that
is in fact the true relative risk – is still quite small in absolute
terms,” Rider said by email. “Given that the benefits of vasectomy
as an effective method of birth control are well established,
vasectomy remains an important contraceptive option.”
For the current study, researchers examined data on almost 364,000
men who were at least 40 years old when they joined a large cancer
prevention study in 1982, including 42,000 men who'd had
vasectomies.
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Over 30 years of follow-up, 7,400 men died of prostate cancer.
Overall, men with a vasectomy had a 1 percent higher risk of dying
from prostate cancer – a difference too small to rule out that it
was due to chance.
When men did develop prostate cancer, those with vasectomy were 9
percent less likely to have lethal “high-grade” cancers, though this
difference was also statistically insignificant.
One limitation of the study was that vasectomy status was reported
by men’s wives, potentially resulting in some under-reporting, the
authors note. Researchers also lacked data on vasectomies performed
after the start of the study.
In this study, as well as in the 2014 research, it’s possible that
men who had vasectomies were screened more often for prostate cancer
or that they were different in some ways from their peers who didn’t
get the sterilization surgery, noted Siobhan Sutcliffe, a public
health researcher at Washington University School of Medicine in St.
Louis who wasn’t involved in either study.
“Another possible explanation for the difference in study findings
is chance,” Sutcliffe said by email. “This is why we investigate
associations in many different study populations so that we can
ultimately draw conclusions from a large body of evidence rather
than from one study.”
SOURCE: http://bit.ly/2cXJUnx Journal of Clinical Oncology, online
September 19, 2016.
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