PHILADELPHIA -- Researchers at the University of Pennsylvania’s Perelman School of Medicine are suggesting that a prophylactic treatment option increasingly offered to breast cancer patients has only a slight benefit, and the modest gains to life expectancy the treatment provides may actually be offset by decreases in quality of life for many patients.

 The treatment, contralateral prophylactic mastectomy, or CPM, is a surgical procedure that removes the unaffected breast in patients with cancer in one breast. Younger women with early-stage disease are often offered this treatment as a preventative measure, whether or not their cancer is genetic in origin.

 “At the outset of the study, we already knew that CPM was not going to help women with locally advanced breast cancers,” said Robert G. Prosnitz, an assistant professor of radiation oncology. “What surprised us, however, was how small the benefits were for women with even the most favorable breast cancers.”

Using a computer-based decision analysis, researchers examined the impact of CPM on life expectancy and quality-adjusted life expectancy among groups of women with newly diagnosed cancer in one breast and no known genetic predisposition to the disease. Studies show that among these patients, there has been a 150 percent increase in this type of surgery in recent years. 

“We suspect that many of the women who elect to undergo CPM are acting on the belief the surgery will substantially reduce their overall risk of dying of breast cancer,” Prosnitz said. “However, our study shows that a woman’s risk of death from her primary breast cancer far outweighs her risk of death from a potential breast cancer developing in the unaffected breast. Additionally, the modest increase in life expectancy resulting from CPM may ultimately be negated by a reduction in quality of life.”

The researchers hope the findings will assist patients and physicians in making informed decisions about treatment strategies, based on a clear understanding of the actual benefits and risks involved in preventive mastectomies and on the potential for the surgery to have an adverse impact on women’s quality of life.

 Prosnitz and his colleagues plan to develop and test decision aids that will help patients better assess their treatment options.

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