Prognostic factors associated with survival in breast cancer patients

Abstract

Introduction/Rationale: Breast cancer is the most common malignancy among women in Brazil and one of the leading causes of cancer-related mortality (Ministry of Health, Estimate 2023: Cancer Incidence in Brazil). Identifying prognostic factors is essential for risk stratification and therapeutic planning. Methods: A retrospective observational study was conducted using data from 272 breast cancer patients treated at the Hospital das Clínicas of the Federal University of Goiás (HC/Universidade Federal de Goiás), obtained from medical records. The studied outcome was breast cancer-specific mortality, tracked up to December 2025, with remaining cases considered censored. Follow-up time was defined as the interval between diagnosis and death or censoring. Survival was estimated using the Kaplan-Meier method. Univariate and multivariate Cox regression models were fitted to evaluate prognostic factors, and a parametric Weibull model was used as a complementary analysis. The study was approved by the Research Ethics Committee of HC/Universidade Federal de Goiás approval no. 6.833.075 and CAAE nº 78349624.5.0000.5078. Results: A total of 18 deaths (6.6%) and 254 censored observations (93.4%) were observed. The 3-year survival probability was 94.0%. The presence of distant metastasis was strongly associated with an increased risk of death in the univariate analysis (HR=14.89; p<0.001), as was lobular histological type (HR=8.24; p=0.008). In the multivariate model, metastasis remained the main independent prognostic factor (HR=13.15; p<0.001), while lobular histology showed borderline significance (HR=6.00; p=0.052). The Weibull model indicated an increasing hazard over time, suggesting risk progression during follow-up. Conclusion: The presence of distant metastasis was the main prognostic factor associated with the risk of death, while lobular histological type exhibited a tendency toward a worse prognosis. These findings may contribute to the prognostic assessment of breast cancer patients.