Social differences in breast cancer survival in relation to patient management within a national health care system (Sweden)

Abstract

Epidemiologic studies have shown that cancer survival is poorer in low compared with high socioeconomic groups. We investigated whether these differences were associated with disparities in tumour characteristics and management. This cohort study was based on 9,908 women aged 20-79 years at diagnosis with primary breast cancer identified in a Swedish population-based clinical register. Information on socioeconomic standing was obtained from a social database. The 5-year cause-specific survival (CSS) and mortality hazard ratios (HR) were estimated by Cox proportional hazard models to assess differences in survival between socioeconomic groups while adjusting for diagnostic intensity, tumour characteristics and treatment. Following adjustment for age, year and stage at diagnosis, the risk of dying of breast cancer was 35% lower among women with high education compared with that of low education (HR = 0.65, 95% CI 0.53-0.80). When compared with women with high education, a lower percentage of women with low education had been investigated for proliferation (84 vs. 76%) or hormone receptor status (89 vs. 81%), had tumours ≤20 mm (68 vs. 64%), were treated at a main hospital (75 vs. 68%) and had received radiation treatment (80 vs. 67%) or chemotherapy (31 vs. 18%). However, these proportional differences could not explain the observed social gradient in survival. To minimize social differences in breast cancer survival, further research should address not only factors leading to inequities in management but also focus on patient factors such as health awareness, comorbidity burden and compliance to adjuvant treatment. © 2008 Wiley-Liss, Inc. Inc.