Vasectomies Linked to Prostate Cancer

Vasectomies may increase a men's risk of prostate cancer, according to a study recently conducted by Medical School researchers.

The average risk to prostate cancer in the U.S. is approximately one in 10. But Dr. Edward L. Giovannucci, instructor in medicine, reported last month in the Journal of the American Medical Association that men who have had vasectomies have an overall 66 percent greater risk of having prostate cancer than those who have not had the operation.

The increased risk for those who had vasectomies 20 or more years ago was 85 percent, compared with those who had not undergone the procedure.

Prostate cancer, the second leading cause of cancer deaths among American men, claimed the lives of 32,000 men in the United States in 1991.

Giovannucci studied more than 10,000 male members of the Harvard Health Professionals Follow-up Study who have had vasectomies, comparing them with about 37,800 members who have not had vasectomies. The study includes dentists, optometrists, pharmacists, and other health professionals.

In a separate study, Giovannucci studied 13,000 men who had vasectomies and 12,000 who did not, all of whom were husbands of participants in the Harvard Nurses' Health Study. He found a 56% overall elevated risk in men and an 89% risk for men who have had vasectomies for 19 years.

"There was a 60% increase in the rate of prostate cancer for men who have had vasectomies," Giovannucci said in a telephone interview yesterday. "This increase was predominantly in men who have had a vasectomy for 20 years."

Giovannucci said the study was relatively unbiased. External variables, including smoking, alcohol intake, diet, and physical activity, were all accounted for in the study design. But he said the results were still not absolutely conclusive.

"We can't definitively say if there is a cause and effect association," he said. "We believe [the study design] raises some concerns that there is true association, but it can't be definitive at this point."

Giovannucci emphasized that the finding does not mean men should avoid vasectomy as a form of contraception.

"We want to make men contemplating vasectomies aware of this but we're definitely not saying that men shouldn't have vasectomies, since it is a good form of contraception," he said.

Dr. Alberto Ascherio, a co-author of the paper and a assistant professor of nutrition and epidemiology at the School of Public Health, agreed that the finding was only one factor for men considering vasectomies.

"We have to compare the cost of vasectomies with the benefits of vasectomies," said Ascherio. "To a large extent, it's an individual decision."