Vasectomies linked to higher cancer risk, but experts see no need to worry

February 17, 1993|By Chicago Tribune

CHICAGO -- Two major studies involving more than 75,000 American men have found a statistical link between vasectomies and an increased risk of prostate cancer.

But experts were quick to downplay the results yesterday, calling them "far too preliminary" for men to consider vasectomy reversal to reduce the risk. A vasectomy is sterilization by cutting the sperm canal.

Nonetheless, while seeking to allay fears, the American Urological

Association recommended that "many men who have had a vasectomy undergo medical procedures used for the early detection of prostate cancer."

The new studies -- both reported by a team headed by Dr. Edward Giovannucci of Harvard's Brigham and Women's Hospital -- appear in today's Journal of the American Medical Association. They deal with the murky statistical area known as relative risk.

Relative risk is a comparison between two incidence rates: cancer or deaths from cancer among people with a particular risk factor compared with those of people without that factor. A person with no risk factors is considered to have a relative risk of 1.0.

One Harvard study, using data from the present 16-year Nurses' Health Study to determine cancer risk, compared 14,607 vasectomized husbands with 14,607 men who had not had the operation. The relative risk of developing prostate cancer in vasectomized men was 1.56.

However, the vasectomized husbands had lower mortality rates than the comparison group, the study found.

The other study evaluated 10,055 vasectomized white male health care professionals -- dentists, veterinarians, osteopaths, optometrists, pharmacists and podiatrists -- and 37,000 unvasectomized colleagues. The relative risk of prostate cancer for vasectomized men rose to 1.66.

"Vasectomy was associated with an overall 66 percent elevated risk of prostate cancer," the researchers wrote. "Men who had had their vasectomies for at least 22 years had an 85 percent elevated risk of prostate cancer."

Such men face an increased risk because of age alone, however.

Approximately 1 of 11 men in the United States will develop prostate cancer, and most of them won't have undergone vasectomies. Prostate cancer has become the second leading cause of cancer deaths among men, killing 32,000 in the United States in 1991. The cause of this cancer is unknown.

Commenting on the results of the new studies, Dr. Giovannucci speculated that because prostatic secretions are reduced after vasectomy, the walnut-sized prostate gland is perhaps more vulnerable to carcinogens.

Commenting on the latest Harvard research, American Urological Association President Dr. H. Logan Holtgrewe called for follow-up studies. "Right now, I think it's important to emphasize that men who have had a vasectomy should not panic and run out to reverse the procedure," he said.

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