Abstract 4014: Prognostic evaluation of breast cancer long-term survival outcomes: contributions from a Brazilian hospital-based cohort
Authors: Alessandra B. de Souza, Daniely R. Freitas-Alves, Taiana S. da Silva, Vanessa Índio-do-Brasil, Rosane Vianna-Jorge
Journal: Cancer Research (2025)

Abstract Breast cancer is currently the second most common neoplasm worldwide and the leading cause of death by cancer among women. Treatment advances based on molecular classification of tumors have contributed to reduce mortality in many developed countries. Nevertheless, the growing incidence worldwide poses additional challenges to adjust prognostic evaluation to changing epidemiological profiles in distinct populations. In this regard, the present study evaluates a current prospective cohort of Brazilian women with primary unilateral and non-metastatic breast carcinoma, who were diagnosed and started treatment between 2009 to 2013 at the Brazilian National Cancer Institute (INCA #129/08). The study aims to characterize the contribution of well-known histopathological characteristics, in combination with clinical and sociodemographic aspects, for prognostic evaluation of survival outcomes. Here, we present the first analyses after completing ten years of follow-up. Survival curves were estimated using the Kaplan-Meier method, and the impact of individual variables on disease-free or overall survival rates was estimated by calculation of their hazard ratios (HR) and 95% confidence intervals (95% CI). Multivariate Cox proportional hazards regression models were used to calculate the adjusted HR (HRadj) and respective 95% CI. Total patient follow-up was 152, 832 person-months, with a median follow-up time per person of 12.5 years (y). Disease-free survival (DFS) was 80.2% (5y) and 64.8% (10y), with a median of 99 months (95% CI 97.8 - 102.0). Overall survival (OS) was 83.1% (5y) and 69.6% (10y), with a median of 98 months (95% CI 96.0 - 100.7). Tumor staging ≥ IIb and molecular classification as HER-2 or triple-negative were prognostic of both DFS and OS, either for 5y- or 10y- models. In addition, obesity was significantly associated with worse DFS (HRadj = 1.554; 95% CI 1.021 - 2.365) and marginally contributing for OS (HRadj = 1.545; 95% CI 0.998 - 2.391), but only in 5y-models. In contrast, the 10y-models indicated worse outcomes for patients who self-reported as black or brown: HRadj = 1.365 (95% CI 1.048 - 1.777) for DFS or HRadj = 1.511 (95% CI 1.051 - 2.171) for OS. It is not clear how color/race is affecting survival in our cohort, as no significant differences were found for clinical or histopathological characteristics at diagnosis. We are currently including data from gene polymorphisms as an attempt to find new molecular biomarkers that might improve prognostic evaluation of breast cancer. Citation Format: Alessandra B. de Souza, Daniely R. Freitas-Alves, Taiana S. da Silva, Vanessa Índio-do-Brasil, Rosane Vianna-Jorge. Prognostic evaluation of breast cancer long-term survival outcomes: contributions from a Brazilian hospital-based cohort [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4014.