Association between poverty and lack of insurance on mortality rates at 1, 2, and 5 years in patients with breast cancer metastatic to the spine: a propensity score-matched analysis of 854 patients.
OBJECTIVE Metastatic cancer to the spine presents a growing challenge in the US, with surgery often recommended for stability and palliation. Despite advancements, postoperative complication and mortality rates remain high. In this study, the authors aimed to investigate the impact of poverty and social determinants of health on survival rates among patients with metastatic breast cancer to the spine. METHODS A propensity score-matched retrospective study of patients aged > 18 years receiving a diagnosis of metastatic breast cancer to the spine between 2006 and 2015 was performed using data from the US Surveillance, Epidemiology, and End Results (SEER) sites in the SEER-Medicare database. Poverty census, dual eligibility, race, tumor characteristics (grade, stage, receptor status), community distress score, education level, insurance status at diagnosis, income level, and marital status were evaluated in the model. RESULTS Of 854 patients, 651 resided in zip codes in which 0% to < 20% of the population lived below the poverty line and 203 patients resided in zip codes in which 20%-100% lived below the poverty line. After propensity score matching, patients living in areas with 20%-100% of the population below the poverty line had worse survival at 1 year (HR 1.43, p = 0.009), 2 years (HR 1.45, p = 0.008) and 5 years (HR 1.5, p = 0.007) after diagnosis. Patients with insurance, both non-Medicaid and Medicaid, respectively, had higher survival at 1 year (HR 0.389, p = 0.009) and (HR 0.429, p = 0.006), at 2 years (HR 0.359, p = 0.003) and (HR 0.444, p = 0.008), and at 5 years (HR 0.446, p = 0.01) and (HR 0.513, p = 0.037) compared with patients with no insurance. CONCLUSIONS This is the first study to demonstrate poverty and insurance status as independent predictors of survival at 1, 2, and 5 years in patients with breast cancer metastatic to the spine.