Do socioeconomic status and comorbidity affect survival in women with breast cancer living in the city of São Paulo, Brazil?

Abstract

e18150 Background: Mechanisms underlying social inequalities in breast cancer (BC) survival are not fully understood, being possibly related to the effects of comorbidity, stage at diagnosis and treatment choices. Our study aimed to assess the effect of comorbidity and socioeconomic status (SES) on BC survival in a large metropolitan area in Brazil with universal health care. Methods: This is a retrospective cohort study including all women with invasive ductal BC treated at the Non-profit Program for Breast Cancer Treatment at Hospital Sírio-Libanês, São Paulo, Brazil, between 2006-2011. Charlson Comorbidity Index (CCI) and other study variables were collected from medical charts. Education and Social Vulnerability Index (SVI) measured individual and neighborhood-level SES, respectively. Kaplan Meier analysis and Cox regression model were used to compare five-year overall survival rates (5y-OS) and to estimate crude (cHR) and adjusted hazard ratios (aHR). Results: Our sample comprised 257 women with median age = 58 years. The majority of patients had more than 8 years of education (59%), and they were submitted mostly to conservative surgery (57.2%). Median follow-up time was 84.9 months. Less educated women presented lower 5y-OS (83.3%) compared to more educated patients (95.1%) (p = 0.069); no differences were found according to SVI (p = 0.515). Comorbidities affected prognosis (CCI 0, 5y-OS = 91.6%; CCI 1+, 5y-OS = 84.0%, p = 0.011). Age (p = 0.023), marital status (p < 0.001), pathologic stage (p < 0.001), adjuvant treatment (p = 0.001), type of surgery (p = 0.013), lymph node dissection (p = 0.016), and medication use (p = 0.045) also have influenced 5y-OS. Multivariate analysis has shown an interaction between education and comorbidity (CCI 0, less educated, aHR = 1.20, 95% CI 0.50-2.85; CCI 1+, more educated, aHR = 1.05, 95% CI 0.26-4.21; CCI 1+, less educated, aHR = 3.90, 95%CI 1.38-11.03) and an independent prognostic effect of widow status (aHR = 3.43, 95% CI 1.51-7.80) (adjusted for age, pathologic stage, adjuvant treatment, and surgery). Conclusions: Comorbidity and SES affect survival in women with BC. Interventions to correct these disparities are crucial to obtain optimal results for all.