Survival Disparities in Non-Small Cell Lung Cancer by Race, Ethnicity, and Socioeconomic Status

Purpose: Non-small cell lung cancer (NSCLC) is among the leading causes of cancer death in the United States. Previous studies found mixed results regarding disparities in survival by race, ethnicity, and socioeconomic status (SES). However, race comparisons were usually limited, with comparisons made between black and white patients only or by merging race and ethnicity together as non-Hispanic black, non-Hispanic white, and Hispanic patients. Even fewer studies included race, ethnicity, and SES together while controlling for extensive confounding variables. Thus, because we have access to a large and unique population-based database that includes tumor characteristics and patient comorbidities, the purpose of this study was to explore disparities in NSCLC survival. Methods: We linked data from the 1996 to 2007 Florida Cancer Data System registry to the Florida's Agency for Health Care Administration and the US Census (n = 98,541). Survival time was from date of diagnosis to death or last contact. Race was white, black, Native American, Asian, Pacific Islander, Asian Indian/Pakistani, or other. Ethnicity was non-Hispanic or Hispanic. Socioeconomic status was measured as percentage of the participant's census tract living below the federal poverty line. Median survival and survival rates were calculated by Kaplan-Meier method. Cox proportional hazards regression models produced unadjusted and adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs). Results: The majority of patients were white (91.9%) and non-Hispanic (94.1%). Blacks had the lowest median survival (8.4 months). At 5 years after diagnosis, survival rate was highest in whites (16.3%) and lowest for Pacific Islanders (6.4%). In the adjusted model, Asians had significantly improved survival compared with whites (HR, 0.85; 95% CI, 0.76-0.95). Patients in middle-low (HR, 0.96; 95% CI, 0.94-0.99), middle-high (HR, 0.92; 95% CI, 0.89-0.94), and highest (HR, 0.87; 95% CI, 0.84-0.91) SES areas had significantly improved survival compared with those in lowest areas. Significantly worse survival was found for patients with complicated diabetes (HR, 1.05; 95% CI, 1.01-1.08), weight loss (HR, 1.08; 95% CI, 1.06-1.11), fluid and electrolyte disorders (HR, 1.08; 95% CI, 1.06-1.11), and alcohol abuse (HR, 1.11; 95% CI, 1.07-1.14). Discussion: We found strong evidence for racial and socioeconomic disparities in Floridian NSCLC survival. Asians had improved survival compared with whites, a novel finding. Our findings confirmed that patients living in lower socioeconomic neighborhoods have worse outcomes than their wealthier neighborhood counterparts. Finally, we found an association between some modifiable factors/comorbidities and worse survival. Clinicians may be able to use this information to improve patients' likelihood of better outcomes.