From Annals of Surgery, “Growing Use of Contralateral Prophylactic Mastectomy Despite no Improvement in Long-term Survival for Invasive Breast Cancer.”
Objective: To update and examine national temporal trends in contralateral prophylactic mastectomy (CPM) and determine whether survival differed for invasive breast cancer patients based on hormone receptor (HR) status and age.
Methods: We identified women diagnosed with unilateral stage I to III breast cancer between 1998 and 2012 within the Surveillance, Epidemiology, and End Results registry. We compared characteristics and temporal trends between patients undergoing breast-conserving surgery, unilateral mastectomy, and CPM. We then performed Cox proportional-hazards regression to examine breast cancer-specific survival (BCSS) and overall survival (OS) in women diagnosed between 1998 and 2007, who underwent breast-conserving surgery with radiation (breast-conserving therapy), unilateral mastectomy, or CPM, with subsequent subgroup analysis stratifying by age and HR status.
Women keep on choosing to have their contralateral breast removed in an effort to prolong like and prevent breast cancer recurrence. This is in spite of evidence showing it does no good. This study used SEER data to examine trends in that behavior.
They identified about half a million women diagnosed with unilateral invasive breast cancer. About 60% of them had breast-conserving surgery. About a third had unilateral mastectomy, leaving about 7% choosing a contralateral prophylactic mastectomy. But that number increased, not decreased, over time. In 2002, under 4% chose that route; in 2012, almost 13% chose it.
Women who choose contralateral prophylactic mastectomy need more surgery in general. About half of such women also get reconstructive surgery, compared to 16% of those who undergo a unilateral mastectomy.
Here’s the kicker, though. With half a million patients available for analysis, they could find no benefit in breast cancer-specific survival or overall survival, even after taking into account hormone receptor status or age. For those of you keeping track at home, in the fully adjusted analyses the Hazard ratios for contralateral prophylactic mastectomy were actually significantly worse compared to breast conservation surgery ( breast cancer-specific survival: HR 1.08, 95% CI 1.01-1.16; overall survival: HR 1.08, 95% CI 1.03-1.14).