934 – Improved survival in breast cancer over two decades in southern brazil: a retrospective cohort study of 2,247 patients

Abstract

Introduction: Breast cancer remains the most prevalent malignancy and the leading cause of cancer-related mortality
among women in Brazil. Over the past two decades, the healthcare landscape has been transformed by advances in diagnostic approaches and personalized therapies, highlighting the need for longitudinal evaluations of the impact of these
changes on clinical outcomes.
Objective: To assess temporal trends in overall survival and to identify prognostic factors in a cohort of breast cancer
patients over a 20-year period.
Methods: This retrospective cohort study included 2,247 women diagnosed between 2002 and 2022 at a reference center
in Southern Brazil. Patients were stratified by decade of diagnosis: Period 1 (2002–2011) and Period 2 (2012–2022). Overall
survival was estimated using the Kaplan–Meier method and compared using the log-rank test. Prognostic factors were
analyzed using a multivariate Cox proportional hazards model (Statistical Package for the Social Sciences, version 18.0),
with statistical significance set at p<0.05.
Results: A significant improvement in overall survival was observed among patients diagnosed in Period 2 compared
to Period 1 (p<0.001). In the multivariate analysis, disease recurrence emerged as the strongest predictor of poor prognosis (hazard ratio [HR] 10.214; 95% confidence interval [CI] 7.714–13.524; p<0.001). Lymph node involvement (HR 1.045 per
node; 95%CI 1.032–1.059; p<0.001), human epidermal growth factor receptor 2 (HER2)-positive status (HR 1.610; 95%CI
1.147–2.261; p=0.006), and absence of hormone receptors (HR 1.616; 95%CI 1.028–2.541; p=0.038) remained independently
associated with worse survival in the adjusted model.
Conclusion: The findings demonstrate a favorable evolution in breast cancer prognosis over the past two decades. The
improvement in overall survival reflects the positive impact of advances in detection strategies and therapeutic approaches.
However, disease recurrence and aggressive biological profiles remain critical challenges, reinforcing the need for rigorous monitoring and access to targeted therapies.
Ethics: Research Ethics Committee Approval (CAAE 53405621.0.0000.5327).
Funding: Coordination for the Improvement of Higher Education Personnel (CAPES), Process No. 88887.503692/2020-00;
Hospital de Clínicas de Porto Alegre, Research and Events Incentive Fund (FIPE), Project No. 2021-0546.