Abstract
Socioeconomic status (SES) has led to treatment and survival disparities; however, limited data exist for non-small cell lung cancer (NSCLC). This study investigates the impact of SES on NSCLC diagnostic imaging, treatment, and overall survival (OS), and describes temporal disparity trends. The Ontario Cancer Registry was used to identify NSCLC patients diagnosed between 2007 and 2016. Through linkage to administrative datasets, patients' demographics, imaging, treatment, and survival were obtained. Based on median household neighborhood income, the Ontario population was divided into five income quintiles (Q1-Q5; Q1 = lowest income). Multivariable regressions assessed SES association with OS, imaging, treatment receipt, and treatment delay, and their interaction with year of diagnosis to understand temporal trends. Endpoints were adjusted for demographics, stage and comorbidities, along with treatments and imaging for OS. A total of 50 542 patients were identified. Higher SES patients (Q5 vs. Q1) showed improved 5-year OS (hazard ratio, 0.89; 95% confidence interval [CI], 0.87-0.92; P < .0001) and underwent greater magnetic resonance imaging head (stages IA-IV; odds ratio [OR], 1.24; 95% CI, 1.16-1.32; P < .0001), lung resection (IA-IIIA; OR, 1.58; 95% CI, 1.43-1.74; P < .0001), platinum-based vinorelbine adjuvant chemotherapy (IB-IIIA; OR, 1.63; 95% CI, 1.39-1.92; P < .0001), palliative radiation (IV; OR, 1.14; 95% CI, 1.05-1.25; P = .023), and intravenous chemotherapy (IV; OR, 1.45; 95% CI, 1.32-1.60; P < .0001). Lower SES patients underwent greater thoracic radiation (IA-IIIB; OR, 0.86; 95% CI, 0.79-0.94; P = .0003). Across 2007-2016, socioeconomic disparities remain largely unchanged (interaction P > .05) despite widening income inequality.