Analysis of breast cancer survival in a northeastern Brazilian state based on prognostic factors: A retrospective cohort study

Abstract

Breast cancer is a major health problem worldwide. Analysis of breast cancer epidemiology in emerging countries enables assessment of prognostic factors, cancer care quality, and the equity of resource distribution. We aimed to estimate the overall (OS) and cancer-specific survival (SS) of breast cancer patients in the northeastern Brazilian state of Sergipe to identify independent prognostic factors. We analyzed a cohort for the factors age at diagnosis, place of residence, time to treatment, staging, and molecular classification, using the Kaplan-Meier method, log-rank test, Pearson's chi-squared test and Cox regression model. The outcome was the vital status at the end of the study. Our analysis showed an OS probability of 0.72 and an SS probability of 0.75. In multivariate analysis, time to treatment within 60 days, stage IV, and triple-negative classification remained independent prognostic factors for both OS [unadjusted hazard ratio (HRp) 1.50 (1.21; 1.86), HRp 16.56 (8.35; 32.85), and HRp 2.73 (1.73; 4.29), respectively] and SS [HRp 1.43 (1.13; 1.81), HRp 20.53 (9.45; 44.56), and HRp 3.14 (1.88; 5.26), respectively]. Better survival was demonstrated for the following patients: Those receiving their first treatment after 60 days, with an OS of 52.5 months (51.2; 53.8) and SS of 53.5 months (52.3; 54.7); stage I patients, with an OS of 58.8 months (57.7; 60.0) and SS of 59.2 months (58.1; 60.3); patients without nodal metastasis, with an OS of 54.2 months (53.0; 55.4) and SS of 55.6 months (54.5; 56.7); and patients with luminal A classification, with an OS of 56.8 months (55.0; 58.5) and SS of 57.8 months (56.2; 59.4). This study identified independent prognostic factors and that OS and SS were lower for patients from Sergipe than for patients in high-income areas. Therefore, determining the profiles of breast cancer patients in this population will inform specific cancer care.