Breast cancer risk reduction among patients with DCIS.

Abstract

1562 Background: The incidence of ductal carcinoma in situ (DCIS) has dramatically increased with widespread mammographic screening. Although risk of recurrence of DCIS is low, it is associated with a higher risk for subsequent contralateral breast cancer (CBC), for which preventive measures are available. We evaluated the uptake of surgical and pharmacologic interventions to reduce CBC risk at our institution and investigated factors that may influence treatment choices for DCIS. Methods: City of Hope (COH) DCIS patients were identified using two sources, the Circulating Breast Tumor Marker (BrTM) Registry and the National Comprehensive Cancer Network (NCCN) database. Datasets were linked together, and treatment variables were cross-tabulated with patient and tumor characteristics. Results: Of 782 patients with breast malignancy diagnosed since 1997, 370 were excluded due to concurrent or prior invasive disease, 8 due to suspected misclassification based on therapies received, and 4 due to treatment on protocol. Of the remaining pure DCIS patients, treatment choices were recorded for 289. Of those, 40 (14%) chose bilateral risk reduction mastectomy (BRRM), 82 (28%) unilateral mastectomy, 165 (57%) lumpectomy, and 2 had no surgery. Hormonal therapy (HT) was recorded for 215 individuals who did not pursue BRRM: 124 (57%) took tamoxifen, 3 of whom switched to raloxifene, 5 (2%) started with raloxifene, and 7 (3%) took an unspecified hormonal agent, for a total HT uptake of 55%. This included 8 of 29 women with ER-negative DCIS who chose HT for CBC risk reduction. Younger age at diagnosis was associated with BRRM (24% of women diagnosed before age 50, 10% of those diagnosed 50-64, and 5% of women 65+ had BRRM, p<0.001) and HT (59% of women <65 chose HT compared to 40% of women 65+, p=0.009). Within ethnic minorities, more Asian women chose BRRM (22% vs 7% of other minorities, p=0.08). Interestingly, fewer high grade DCIS women opted for HT (39% vs 55% for low to intermediate grade, p=0.06). Conclusions: Young women tend to pursue surgical prophylaxis. Among women who keep their breasts, HT uptake was high across all age and ethnic groups, except for those older than 65 at diagnosis. It is unclear if this is due to patient choice or reflects age bias in physician recommendation.