The study looked at data from a small fraction of the estimated 200,000 women who receive breast cancer diagnoses in the United States each year. If the figures are correct 8,000 to 10,000 patients a year may be electing to have the procedure, called a contralateral prophylactic mastectomy.
"Some people may think it's kind of crazy, but you don't know what you're going to do until you yourself are faced with the situation," says Darcy Long, 44, of Maple Grove, Minn., who had a double mastectomy after breast cancer was diagnosed in her right breast last July.
She explains why: "There was no question in my mind. I was going to have a mastectomy on both sides. I wanted to maximize my survivability, and I didn't want to ever think that I hadn't done everything that I possibly could to prevent this from coming back."
According to lead author Dr. Todd M. Tuttle, chief of surgical oncology at the University of Minnesota Medical School, the initiative to conduct the study was provided by the increasing numbers of patients requesting the procedure.
Still, he says he was surprised by the increase in contralateral prophylactic mastectomies, an upward trend that is showing no sign of leveling off and is occurring even as the practice of breast-conserving surgery expands.
"The comment patients make is, 'I just want to be done with it,'" he says. "They never want to have another mammogram again; they never want to have another biopsy again."
Yet Tuttle and others emphasize that though the removal of the healthy breast sharply reduces the risk of a new cancer developing in that breast — the risk is not zero because some tissue can remain.
"For the vast majority of our patients, this does not impact the chances of dying of breast cancer, and that's the key thing here," says Dr. Julie R. Gralow, the chairwoman of the communications committee of the American Society of Clinical Oncology and an associate professor of medical oncology at the University of Washington and the Fred Hutchinson Cancer Research Center in Seattle.
"My first reaction to this study, because it came as a bit of a surprise, was, 'Oh, are we doing our job explaining that point to patients?'" Dr. Gralow says. "We want to support women in doing what feels right to them. But our job is to make sure they have all the accurate information."
The study looked at data from cancer surveillance registries covering about a quarter of the United States to identify 152,755 patients whose cancer was diagnosed in one breast from 1998 to 2003. The rate rose steadily, with 4.5 percent of all patients who received breast cancer diagnoses in 2003 having the surgery, up from 1.8 percent in 1998.
The numbers were much higher among women who had the breast with cancer removed, rather than a lumpectomy. That group was much more likely to choose to have the healthy breast removed, as well. In that group, 11 percent chose a double mastectomy in 2003, up from 4.2 percent in 1998. Patients with Stage 1 breast cancer chose the procedure more often than those with more advanced cancer.
"What we're actually seeing is more and more women at the two extremes: either having minimal surgery, a lumpectomy, or having a bilateral mastectomy," Dr. Tuttle said. "Fewer women are having just one breast removed."
One more reason could be cosmetic. Advances in medical treatments mean that doctors have better reconstruction methods for women who have both breasts removed. In fact, the reconstruction of a patient's breasts occurs during the mastectomy - leaving women with immediate results.
Christi, a 30-year-old Utah woman, was recently diagnosed with the cancer after she felt a lump in one of her breasts. Despite her young age, she opted to have a surgeon remove both of her breasts for both peace of mind - and the solace of knowing that she would emerge from the surgery looking almost the same as she did going in.