Abstract P2-14-05: Adjuvant chemotherapy in elderly women with triple-negative breast cancer: Swedish registry data 2009-2017

Abstract

Abstract Background: Breast cancer incidence is strongly related to age, with the highest incidence rates being in elderly women. Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer associated with worse survival. Due to competing mortality risks and co-morbidities, TNBC in the elderly is often under-treated with adjuvant chemotherapy. The aim of this study was to investigate if there is a gain in both breast cancer specific survival (BCSS) and overall survival (OS) with adjuvant chemotherapy in elderly patients with TNBC. Method: Information from all patients 70 years and older diagnosed with primary TNBC during the years 2009-2017 were retrieved from the Swedish National Register for Breast Cancer, the Swedish Cause of Death Register and the Swedish Patient Register. Both a propensity score matched (PSM) model and a Cox-regression model was created examining the effect of age, tumor size, tumor grade, nodal status, co-morbidities (Charlson/Deyo) and chemotherapy treatment, on BCSS and OS. Results: Of the 1421 patients included, 428 (30.1%) received chemotherapy. The 5-year BCSS was 84% vs. 62% in favor for patients receiving chemotherapy. The 5-year OS was 80% vs. 46% in favor for patients receiving chemotherapy. When adjusting for the co-variates using PSM, the 5-year BCSS was 84% vs. 73% (p<0.004) and the 5-year OS was 79% vs. 62% (p<0.001) favoring chemotherapy. Discussion: In this PSM registry analysis including all patients ≥70 years in Sweden with TNBC during a 9-year period, we could show that there was a significant benefit in both BCSS and OS with adjuvant chemotherapy when adjusting for both age and co-morbidities. Cox multivariate regression model for breast cancer specific survivalHazard Ratiop-value95% CIChemotherapy0.6020.0020.435-0.834Age (years)1.0510.0001.030-1.072Tumor size (mm)1.0170.0001.012-1.022Stage N11.9090.0001.488-2.450Stage N24.8550.0011.978-11.916Stage N31.9060.5210.266-13.637Grade 21.0140.9790.365-2.813Grade 31.6220.3400.601-4.374Charlson score1.1940.0570.995-1.433 Citation Format: Slavica Janeva, Chenyang Zhang, Anikó Kovács, Toshima Z Parris, Anna-Karin Tzikas, Christopher M Pezzi, Riccardo A Audisio, Roger Olofsson Bagge. Adjuvant chemotherapy in elderly women with triple-negative breast cancer: Swedish registry data 2009-2017 [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-14-05.