Abstract P2-13-01: Stage-related risk categorization and influence of free margins on survival in triple negative early breast cancer - a population-based study of 2037 TNBC patients with adjuvant chemotherapy

Abstract

Abstract Introduction: Triple negative breast cancer (TNBC) represents 10-20% of all breast cancer entities [1][2] and has a known aggressive behavior and poor outcome. Patients treated in the setting of randomized clinical trials often do not represent actual treatment characteristics in real-life scenarios. To determine the stage-related survival and effect of surgical performance in TNBC with current multimodal treatment, we set out to analyze data of a large population-based registry of primary breast cancers which covering >50% of all breast cancer cases in Germany. Patients and methods: We analyzed data from a prospectively collected cancer registry of >200 certified breast units of the West-German Breast Center (WBC) in Germany from 2009-2011. From a cohort of 39570 primary breast cancer patients treated in this period, 12759 underwent adjuvant systemic therapy, out of which 2037 were TNBC cases with adjuvant chemotherapy. Inclusion criteria were triple negative breast cancers (Her2-new1+/2+ (Fish negative) and estrogen receptor (ER) and progesterone receptor (PR) <10%) and adjuvant chemotherapy, unilateral and non-metastasized breast cancer. Only those patients were included who have been followed-up within the first 3 years. Exclusion criteria were neoadjuvant chemotherapy, bilateral breast cancer and metastatic disease. The use of first, second and third generation chemotherapy was analyzed as well as the effect of clear/unclear resection margins and its impact on survival data. Results: 2037 patients were eligible for this study. Overall survival rates were as follows: T1 a and T1b 100 %, T1c 90,7 %, T2 90,9 %, T3 68,1 % and T4 64,3 %. No statistical differences were detected in between stages T1 and T2, and also not in between T3 and T4. Combining T1/T2 and T3/T4 and performing group-wise comparisons, differences for combined stages were highly statistically significant (3,9 x E-09). Inflammatory TNBC was prognostically worst with a survival-rate of 33,3 % at 24-months. (p<0,001) Unclear resection-margins versus clear margins in TNBC exerted a negative impact on DFS (87 vs. 73 %; p=0,00002) and DDFS (p=0,0004). Age was an independent risk factor for survival with a cut-off at 35 years.(p=0,044) Third-generation chemotherapies (anthracycline+taxanes) were associated with a significant improved overall-survival at 24-months compared to first generation chemotherapies (non-anthracycline, non-taxane) (95 % vs. 87 %; p=0,0029) Conclusion: Standard 3rd generation (anthracycline- and taxane-containing) chemotherapy and optimal surgical performance with clear margins is vital for patients with early, triple-negative breast cancer (TNBC). Within T1 and T2 stages, no stage-related deterioration of prognosis was detected, however these stages were markedly different from stages T3/T4, declining from 90-100% to 64-68 %. This analysis of a large database of a population-based study demonstrates that tumor size, margins and guideline-adapted chemotherapy matter in triple-negative, early breast cancer. [1] Schwentner et al. 2013 [2] Elsawaf et al. 2013. Citation Format: Peter Kern, Gunter von Minckwitz, Carolin Pütter, Annika Flach, Sofia Pavlidou, Rainer Kimmig, Mahdi Rezai. Stage-related risk categorization and influence of free margins on survival in triple negative early breast cancer - a population-based study of 2037 TNBC patients with adjuvant chemotherapy [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 P2-13-01.