Abstract P1-16-02: Multidisciplinary breast cancer care is associated with a higher rate of breast conservation in comparison with non-multidisciplinary care

Abstract

Abstract Background Mastectomy rates, both therapeutic and prophylactic, are on the rise in the United States. After recent implementation of a multidisciplinary breast clinic for newly diagnosed women at our institution, we sought to examine the impact of multidisciplinary care on surgical decision making. Materials/Methods Women with newly diagnosed breast cancer at our institution are referred to a multidisciplinary breast clinic where they are seen by a team of breast specialists (MDC) or to an individual practitioner (non-MDC) for initial consultation. We retrospectively analyzed rates of breast conserving surgery (BCS) and mastectomy among women with newly diagnosed breast cancer seen in either setting. For mastectomy cases, we designated the mastectomy as clinically indicated vs not clinically indicated based on National Comprehensive Cancer Network (NCCN) guidelines for breast conservation. T-test and chi-square were used to examine the comparability between MDC and non-MDC cohorts. Logistic regression was used to evaluate the overall prevalence of BCS among MDC and non-MDC cohorts. Stratification analysis was further conducted to examine BCS rates among women in each cohort receiving neoadjuvant chemotherapy vs up front surgery. Results A total of 341 consecutive patients were analyzed, including 202 MDC and 139 non-MDC patients seen in initial consultation between June 2012 and April 2014. The MDC and non-MDC cohorts were statistically equivalent in terms of age, tumor and nodal stage, histology, biomarker status, receipt of neoadjuvant chemotherapy, and proportion with genetic mutations. In the MDC cohort, 66% underwent BCS vs 42% in the non-MDC cohort (p<0.0001). Of those receiving neoadjuvant chemotherapy, 37% in the MDC cohort underwent BCS vs 12% in the non-MDC cohort (p=0.08). Of those proceeding to surgery without neoadjuvant therapy, 70% underwent BCS in the MDC cohort vs 46% in the non-MDC cohort (p<.0001). Among mastectomies performed in the MDC vs non-MDC cohorts, 77% and 41% respectively were clinically indicated (P<.0001). Rates of unnecessary contralateral prophylactic mastectomy were comparable in both groups, 39% (p=0.99). Conclusions Breast cancer patients seen in an MDC setting at the time of initial diagnosis are significantly more likely than women seen in a non-MDC setting to undergo breast conservation. We hypothesize that the MDC model of breast cancer care, via facilitation of more informed medical decision making, may be a viable strategy to curtail rising mastectomy rates in the United States. Citation Format: Caitlin L Gomez, Pin-Chieh Wang, Nicole A Dawson, Robyn L Dvorak, Nova Foster, Anne Hoyt, Sara A Hurvitz, Amy Kusske, Charles Y Tseng, Susan A McCloskey. Multidisciplinary breast cancer care is associated with a higher rate of breast conservation in comparison with non-multidisciplinary care [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-16-02.