Racial disparities in staging, treatment, and mortality in non-small cell lung cancer

Background: Black race is associated with advanced stage at diagnosis and increased mortality in non-small cell lung cancer (NSCLC). Most studies focus on race alone, without accounting for social determinants of health (SDOH). We explored the hypothesis that racial disparities in stage at diagnosis and outcomes are associated with SDOH and influence treatment decisions by patients and providers.

Methods: Patients with NSCLC newly diagnosed at Indiana University Simon Comprehensive Cancer Center (IUSCCC) from January 1, 2000 to May 31, 2015 were studied. Multivariable regression analyses were conducted to examine the impact of SDOH (race, gender, insurance status, and marital status) on diagnosis stage, time to treatment, receipt of and reasons for not receiving guideline concordant treatment, and 5-year overall survival (OS) based on Kaplan-Meier curves.

Results: A total of 3,349 subjects were included in the study, 12.2% of Black race. Those diagnosed with advanced-stage NSCLC had a significantly higher odds of being male, uninsured, and Black. Five-year OS was lower in those of Black race, male, single, uninsured, Medicare/Medicaid insurance, and advanced stage. Adjusted for multiple variables, individuals with Medicare, Medicare/Medicaid, uninsured, widowed, and advanced stage at diagnosis, were associated with significantly lower OS time. Black, single, widowed, and uninsured individuals were less likely to receive stage appropriate treatment for advanced disease. Those uninsured [odds ratio (OR): 3.876, P<0.001], Medicaid insurance (OR: 3.039, P=0.0017), and of Black race (OR: 1.779, P=0.0377) were less likely to receive curative-intent surgery for early-stage NSCLC because it was not a recommended treatment.

Conclusions: We found racial, gender, and socioeconomic disparities in NSCLC diagnosis stage, receipt of stage-appropriate treatment, and reasons for guideline discordance in receipt of curative intent surgery for early-stage NSCLC. While insurance type and marital status were associated with worse OS, race alone was not. This suggests racial differences in outcomes may not be associated with race alone, but rather worse SDOH disproportionately affecting Black individuals. Efforts to understand advanced diagnosis and reasons for failure to receive stage-appropriate treatment by vulnerable populations is needed to ensure equitable NSCLC care.