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Contralateral prophylactic mastectomy yielded small survival benefit
Contralateral prophylactic mastectomy provided only a minimal improvement in 20-year survival rates among women with unilateral breast cancer, according to recent findings.
“The use of contralateral prophylactic mastectomy (CPM) among women with unilateral breast cancer has markedly increased in the United States during the past decade,” Pamela R. Portschy, MD, of the department of surgery at the University of Minnesota, Minneapolis, and colleagues wrote. “Breast cancer patients report that the main reason they choose CPM is worry about the risk of contralateral breast cancer, yet they tend to substantially overestimate their risk of developing contralateral breast cancer.”
To evaluate the survival benefit of CPM, researchers designed a Markov model decision tree to yield simulated survival outcomes in women undergoing CPM vs. those who did not. The model included women who had stage I and stage II breast cancer without BRCA mutations.
The researchers then stratified women by age at breast cancer diagnosis (aged 40, 50 or 60 years), breast cancer primary stage (I or II) and ER status.
Using the model, the researchers followed each cohort longitudinally through different health states and calculated the likelihood of developing contralateral breast cancer and dying of primary breast cancer. Life expectancy benefits, overall 20-year survival and DFS were calculated for each treatment approach based on age, cancer stage and ER status.
The researchers determined that the projected life expectancy benefit conferred by CPM ranged from 0.13 to 0.59 years in women with stage I disease, and from 0.08 to 0.29 years for patients with stage II breast cancer. The differences in absolute 20-year survival ranged from 0.56% to 0.94% in women with stage I breast cancer, and from 0.36% to 0.61% in women with stage II disease.
According to study results, younger women derived a greater survival benefit from CPM than older women, as did women with stage I and ER-negative breast cancer. Based on sensitivity analyses, the maximum 20-year survival benefit conferred by CPM was only 1.45%.
“Survival estimates derived from our model may be useful for physicians and breast cancer patients to arrive at evidence-based informed decisions regarding CPM,” Portschy and colleagues wrote. “Moreover, the use of accurate and easily understood decision aids may reverse some of the mastectomy trends recently observed in the United States.”
Disclosure: The researchers report no relevant financial disclosures.