01:40 - Source: CNN

Story highlights

A new study has shown no association between vasectomies and prostate cancer

The findings go against previous research that said the two are linked

CNN —  

When men think of undergoing a vasectomy, they might have a few concerns: fears of pain, worries it won’t work and concerns about their sex life afterward.

Also common is the fear that the snip will increase their risk of cancer, namely of the prostate, with previous research finding a link between the two.

But a new study is laying some of that fear to rest. There’s new evidence that there is no association between having a vasectomy and developing prostate cancer.

“The overall weight of all of the evidence is that vasectomy is unlikely to meaningfully increase risk of any type of prostate cancer,” said Dr. Eric Jacobs, a cancer epidemiologist at the American Cancer Society who led the study.

Prostate cancer is the second most common cancer among men in the United States, second only to melanoma.

Going against the past

Vasectomies are a long-term approach to birth control. The procedure involves cutting, sealing or blocking the tubes that sperm move along when leaving the testicles, so sperm cannot be released during sex. The prostate gland is in close proximity to these tubes, located behind them and involved in adding fluids to semen when needed.

A major study conducted on health professionals in 2014 was the first large-scale study to find an association between having a vasectomy and developing prostate cancer. The underlying biology is unknown, but the study showed a 10% increase in the risk of developing this form of cancer, as well as a 20% higher risk of fatal prostate cancer, among men who had a vasectomy compared with those who did not.

But experts agreed that the overall risk found was low and that with the addition of this new study, published Monday in the Journal of Clinical Oncology, concerns around the link can be lowered.

The current and previous studies were similar in size in terms of the number of participants with any form of prostate cancer, Jacobs said, but his new research had greater insight into the likelihood of developing fatal forms of the cancer. It included more than 7,000 people who died of prostate cancer, compared with 800 in the 2014 study.

“The strength of this study is the size of the cohort” with fatal prostate cancer, said Dr. Charlotte Bevan, professor of cancer biology at Imperial College London, who was not involved in the research. “With this size, you’re more likely to see meaningful associations and avoid coincidence.”

But Bevan noted that the findings of the previous study should not be ignored, as its scale and attention to detail also provide good insight. “The first study updated information on participants as it went along, such as weight and whether they smoke,” she said. These are known risk factors for prostate cancer. “Some of these things will change over the study.”

Bevan agreed that both studies provide evidence for the overall risk being low. “I think we need to look at the overall weight,” said Jacobs. “And my impression is that there is no increase in meaningful risk.”

Removing the risk

Researchers at the American Cancer Society analyzed data from more than 363,000 men – including 42,000 known to have undergone a vasectomy – who were participants of the broader ongoing Cancer Prevention Study II, which began in 1982. All the men were older than 40, the typical age range for men contemplating, and having, a vasectomy. About 7,400 participants died of prostate cancer over the 30-year period of the study.

There was no difference in prostate cancer development between those who did and did not have a vasectomy.

“Vasectomy is a quick, inexpensive, long-term method of birth control. … If there’s no increased in risk, nobody should be discouraged,” Jacobs said. “We wanted to help inform that decision.”

About 10% of middle-age men in the United States have had a vasectomy, said Jacobs.

The team hopes the findings alleviate any concerns among men contemplating the procedure.

Previous concerns

The link between having the snip and developing prostate cancer has long been debated. “There have been some concerns about vasectomy since about 1993,” Jacobs said.

Though the 2014 study found a small rise in risk, other reviews that analyzed a range of previous studies had concluded that there was no association.

“It’s not clear why our two [larger] studies saw differences in risk,” he said. “There’ll probably be a few other studies in the next few years.”

For now, Jacobs said, he would feel reassured by this finding if considering a vasectomy.

It is estimated that one in seven men in the United States will be diagnosed with prostate cancer during their lifetime, but Jacobs believes a vasectomy will not be the underlying cause, particularly among those with fatal prostate cancers.

Follow CNN Health on Facebook and Twitter

  • See the latest news and share your comments with CNN Health on Facebook and Twitter.

“Men concerned about developing a fatal prostate cancer should focus on maintaining a healthy weight and, if they smoke, quitting smoking,” Jacobs said, as these are two well-known risk factors for developing more aggressive, fatal forms of prostate cancer. “Both obesity and smoking have consistently been linked with higher risk of fatal prostate cancer as well as with risk of many other diseases.”

“This large study didn’t show any link between having a vasectomy and the risk of dying from prostate cancer,” said Dr. Jasmine Just, health information officer at Cancer Research UK. “We need more research into the factors that affect prostate cancer risk. But you can reduce the overall risk of cancer by not smoking, keeping a healthy weight and enjoying a healthy balanced diet.”