A new report, published Wednesday in JAMA by researchers at the American Cancer Society and the Dana Farber Cancer Institute, finds the number of male breast cancer patients who undergo prophylactic mastectomy is steadily on the rise. The study found the rate of male breast cancer patients who choose to have CPM nearly doubled, from 3 percent to 5.6 percent, between 2004 and 2011. This is equal to a relative increase of 86.7 percent. By comparison, the rate of CPM among female breast cancer patients increased from 4.5 percent to 11 percent between 2003 and 2011.

“We don’t know why it’s happening in men, but we do know the sociodemographic factors that have been associated with contralateral prophylactic mastectomy in women are also associated with men,” says Ahmedin Jemal, vice president of surveillance and health services research at the American Cancer Society and author of the study. As with women, male breast cancer patients who opt for CPM are more likely to be young, white and privately insured.

For the report, Jemal and his fellow researchers analyzed breast cancer treatments among 6,332 men who opted to have only the breast with cancer removed, between 2004 and 2011. The report is based on data from the North American Association of Central Cancer Registries.

While breast cancer in men is rare, men with who are afflicted with the disease are more likely than women to develop breast cancer in their healthy breast at some point in the future. Men who are breast cancer survivors have a twentyfold increased risk for breast cancer, compared with men who don’t have a history of the disease, Jemal says. Comparatively, women who are breast cancer survivors are up to five times more likely to be diagnosed with breast cancer than the healthy population.

The broad increase in CPMs has occurred despite a lack of research to show the procedure can affect patients’ survival rates. Some experts point to the impact of genetic testing and the “Angelina Jolie effect.” Two years ago, the actress went public with her decision to undergo a preventive double mastectomy after learning she carried the BRCA1 gene mutation, which significantly raises the risk for the disease by as much as 87 percent.

However, Jemal points out that the data indicate the trend began well before the Jolie news. One contributing factor to the decade-long trend may be that most insurance companies are now required to cover breast reconstructive surgery, which makes the decision for some patients much easier.

Jemal says it’s important for male patients to ask a physician about their individual risk for contralateral breast cancer before making any decisions about the surgery. “Men can benefit from this procedure,” he says. “What they need to do is talk to their doctors about the benefits, risks and costs. It’s only the patients at high risk who are likely to benefit from the procedure. They need to discuss with the doctor if they’re a candidate. They have to have the information so they can make an informed decision, but it has to be based on scientific evidence.”