Survival and prognostic factors of patients with breast cancer in the state of São Paulo

Abstract

Introduction Breast cancer is a public health problem worldwide, being the most common malignant neoplasm in the female population. Objectives To estimate 5- and 10-year breast cancer-specific survival probabilities of patients included in the hospital-based cancer registry (HBCR) of the Fundação Oncocentro de São Paulo (FOSP, in Portuguese) and to assess the prognostic factors for this neoplasm. Methods Historical cohort study that included women with breast cancer included in HBCR-FOSP and diagnosed between 2002 and 2012. The event of interest was breast cancer-specific mortality. Living cases at the end of follow-up (December 31, 2017), loss to follow-up and death other than that due to breast cancer were considered censored on the date of the last contact or date of death. Descriptive analysis and survival analysis were performed using the Kaplan-Meyer method. Survival curves were compared using the log-rank test. Hazard ratios (HR) and their 95%CI were estimated using Cox's proportional hazards model. The study was approved by the Human Research Ethics Committee of the Botucatu Medical School, São Paulo State University, Brazil. Results 53,146 cases of invasive breast cancer were registered at HBCR-FOSP between 2002-2012. The median age at diagnosis was 55.9 years. By the end of the follow-up, 20,683 patients died, and 71.4% were due to breast cancer. The 5- and 10-year breast cancer-specific survival for the entire cohort was 76.1% (95%CI 75.7-76.5%) and 64.8% (95% CI 64.2-65.3%), respectively. In the multivariate analysis, the factors associated with prognosis were age at diagnosis, year of diagnosis, educational level, clinical stage, and histological type. Conclusions These findings may contribute to the development of policies for the identification of breast tumors at earlier stages. Key messages Breast cancer is an important public health problem in Brazil and worldwide. The findings of this study may contribute to the development of public policies for the control of breast cancer in the state of São Paulo.