Abstract P2-18-09: TBCRC 013: A prospective analysis of the role of surgery in stage IV breast cancer

Abstract Background: Retrospective studies suggest that primary breast surgery is associated with improved overall survival (OS) in Stage IV breast cancer. TBCRC 013 is a multi-center prospective registry study evaluating the role of surgery for the primary tumor in Stage IV disease. Methods: From 7/09 - 4/12, 128 eligible pts from 14 sites were enrolled in two cohorts (A: Stage IV with intact primary tumor (n = 112); B: metastases (mets) within 3 months of primary surgery (n = 16)). Baseline patient and tumor characteristics, and surgery of the primary were correlated with 2yr overall survival (OS) using log rank, Kaplan Meier and Cox regression for all patients. Comparisons were also made between cohorts A and B and within cohort A stratified by response to systemic therapy. Responders included those with any response (partial,complete) or stable disease at distant sites. Results: Median pt age was 52yrs(21-79) and median primary tumor size 3.2cm(0.7-15). Phenotypes were ER+ 106 (83%), HER2neg 91(71%), and triple neg 10(8%). 60(47%) had bone-only mets. The only significant baseline difference between cohorts A and B was the presence of palpable nodes (A:62% vs B:0%, p<0.001). There were no differences in age, tumor size, ECOG scores, ER or HER2 status, number or sites of mets between cohorts A and B. At a median follow-up of 25 mo (95%CI, 23-31), 2yr OS for all pts is 86% (80-92) and is superior in cohort B as compared to A, (100% vs 84%, p = 0.03). On multivariate analysis (MVA) including all pts, only surgery, ER and HER2 positivity were associated with improved OS (table). Among 112 pts with an intact primary (Arm A), 17(15%) were non-responsive (NR) to systemic therapy, 3(18%) of whom required palliative surgery at a median time of 10.4mos. 2yr OS among NR was 33% (15-69) as compared to 94% (88-99) in Arm A responders (R) (p<0.001). ER positivity was the only baseline difference between NR (65%) and R (88%) within Arm A (p = 0.02). Among 94(85%) Arm A responders, 39(41%) had elective surgery (median 8.4 mos, 95%CI:6.9-10.3) and only 1 of the remaining 47(2%) required palliation. When limited to Arm A responders, elective surgery was not associated with improved 2yr OS (surgery vs not: 94% vs 92%, p = 0.5). Median time to progression following elective surgery was 12 mos (95%CI,8-19mos). When cohort B (n = 16) and cohort A surgery groups (n = 39) are combined, surgery of the primary tumor is associated with improved 2yr OS (96% vs 74%, p = 0.002). Conclusions: In this prospective registry study, patients diagnosed with mets within 3 months of primary breast surgery have an improved 2yr OS. When all pts having surgery (A + B) are examined, surgery is associated with improved OS on MVA, but when limited to Arm A responders, elective surgery does not improve OS. Given that the number of Arm A responders is small, results from the prospective randomized trial will be needed to address this question. These data also demonstrate that the need for surgical palliation of the primary tumor is uncommon in the modern era. Multivariate Analysis for OSN = 128HR Death (95%CI)pvalueSurgery0.28 (0.10-0.74)0.01ER positivity0.28 (0.10-0.72)0.01HER2 positivity0.21 (0.06-0.74)0.01MVA included: age, tumor size, ECOG, ER, PR, HER2, met sites, and surgery Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-18-09.