Purpose: Overall, breast cancer mortality has been declining in the United States, but survival studies of patients with stage IV disease are limited. The aim of this study was to evaluate trends in and factors affecting survival in a large population-based cohort of patients with newly diagnosed stage IV breast cancer.
Patients and methods: We searched the Surveillance, Epidemiology, and End Results registry to identify female patients with stage IV breast cancer diagnosed between 1988 and 2003. Patients were divided into three groups according to year of diagnosis (1988 to 1993, 1994 to 1998, and 1999 to 2003). Survival outcomes were estimated by the Kaplan-Meier method, and Cox models were fit to determine the characteristics independently associated with survival.
Results: We identified 15,438 patients. Median age was 62 years. Median follow-up was 16 months, 18 months, and 11 months in periods 1988 to 1993, 1994 to 1998, and 1999 to 2003, respectively. Median breast cancer-specific survival was 23 months. In the multivariate model, earlier year of diagnosis, grade 3 disease, increasing age, being unmarried, hormone receptor-negative disease, and no surgery were all independently associated with worse overall and breast cancer-specific survival. With each successive year of diagnosis, black patients had an increasingly greater risk of death compared with white patients (hazard ratio, 1.03; 95% CI, 1.00 to 1.06; P = .031).
Conclusion: The survival of patients with newly diagnosed stage IV breast cancer has modestly improved over time, but these data suggest that the disparity in survival between black and white patients has increased.