Patient characteristics associated with the decision to undergo bilateral prophylactic mastectomy for lobular carcinoma in situ.

148 Background: Women at increased risk for breast cancer due to a diagnosis of lobular carcinoma in situ (LCIS) have three management options: high risk surveillance +/- chemoprevention (CP) or bilateral prophylactic mastectomy (BPM). Among a large cohort of women with LCIS, we previously reported there were no differences between women choosing CP compared to those choosing surveillance alone. The purpose of this study was to identify patient factors associated with the decision to pursue BPM for LCIS.,We reviewed our prospectively maintained LCIS database to identify women choosing BPM (1995-2009). Comparisons were made between patients who chose BPM versus those who chose high risk surveillance +/- CP.,Among 995 pts with LCIS, 795 (80%) chose surveillance alone, 149 (15%) chose CP and 51 (5%) chose BPM. Compared to patients electing surveillance +/- CP patients who pursued BPM were younger at age of LCIS diagnosis (48 vs. 52 yrs, p < 0.001), more likely to have bilateral biopsies with LCIS (14% vs. 3%, p = 0.002) and more likely to be premenopausal (82% vs. 57%, p < 0.001). Patients choosing BPM were also more likely to have additional risk factors for breast cancer including: stronger family histories and extremely dense breasts (Table). Occult breast cancer was found in 4 (8%) BPM patients. At a median follow-up of 54 months (range 0-190 mos), 120/944 (13%) patients in the surveillance +/- CP group developed breast cancer.,High-risk surveillance alone is the preferred management option for women with LCIS at our institution. Patients electing BPM are younger and more likely to have other associated risk factors for developing breast cancer. Further research to define how the increased risk imparted by LCIS is augmented by these factors may allow for better risk stratification and more informed discussions with patients. [Table: see text].