Healthcare-Related Determinants of Breast Cancer Prognosis in São Paulo, Brazil: a population-based cohort

PURPOSE/OBJECTIVE: To compare demographic characteristics, stage at diagnosis, treatment patterns, and survival outcomes of breast cancer patients treated in Brazil's public and private healthcare systems. MATERIALS AND METHODS: This retrospective cohort study analyzed data from the Fundação Oncocentro de São Paulo, including women diagnosed with invasive breast cancer between January 2000 and June 2020. Overall survival (OS) was estimated using Kaplan-Meier methods and log-rank tests. Prognostic factors were evaluated using Cox proportional hazards models. RESULTS: A total of 65,543 patients were included. Age distribution was similar between the public and private sectors. However, early-stage diagnoses (stages I and II) were significantly more frequent in the private sector (77.8%), whereas the public system had a higher proportion of patients diagnosed at advanced stages (67.8% in stages II and III) and with metastatic disease (11.1% vs. 5.3%). The proportion of patients receiving surgery and at least 2 adjuvant therapies (trimodal therapy) was comparable between sectors (46.6% private vs. 46.2% public). Survival analysis demonstrated consistently higher 5- and 10-year OS across all stages in the private sector. Ten-year OS by stage was: I-81.6% (private) versus 77.5% (public), P < .001; II-74.0% vs. 63.3%, P < .001; III-55.6% versus 39.6%, P < .001; IV-7.6% versus 6.4%, P = .306. Multivariate analysis identified treatment in the private sector, younger age at diagnosis, higher education level, receipt of trimodal therapy, and earlier stage as independent predictors of improved OS. CONCLUSION: Breast cancer patients treated in the public healthcare system in Brazil more often present with advanced disease, which is associated with inferior survival outcomes.