The effect of various social determinants of health on overall survival in the SCLC population.
Authors: Mirsky Matthew M , Lee Chan Mi , Li Joy , Mitchell Carley , Zhang Annie , Zhong Jeffrey , Fu Pingfu , Margevicius Seunghee P , Cullen Jennifer , Dowlati Afshin , Hsu Melinda Laine 
Published: June 2023

8588

Background: Small cell lung cancer (SCLC) comprises 10-15% of all lung cancers yet little is known about the impact of social determinants of health (SDOH) on outcomes in patients with SCLC. This study aims to assess the impact of various SDOH on overall survival (OS) in patients diagnosed with SCLC at a single institution. Methods: We have established a large clinical/pathologic/genomic database of all patients diagnosed and treated for SCLC between 1998-2022 at our institution for retrospective study. Demographic data including sex, race, age, stage, address, and smoking status were collected. Poverty index was assessed by percent of school-aged children in poverty at the school district level based off 2021 census using the SAIPE tool and stratified as low (poverty index <=15.1) and high (poverty index >15.1). Water/Air carcinogens were obtained by zip code through EPA TRI Explorer database at year of SCLC diagnosis. Food desert designation was acquired through USDA low income and low access atlas at 0.5 miles for urban residences and 10 miles for rural residences respectively. Violent crime rates were obtained from the FBI Crime Data Explorer by year of diagnosis and police department jurisdiction. OS was computed from date of diagnosis to death or last known follow up date, and univariate Cox proportional hazards (PH) regression analysis was performed. Factors that were significant at significance level of 0.25 in univariate analysis were further evaluated using multivariable Cox PH model. Results: A total of 982 patients with SCLC were included. Univariate PH analysis demonstrated statistically significant improvement in OS with younger age (HR = 1.03, 95% CI 1.02-1.03, p <0.0001), female sex (HR = 0.8, 95% CI 0.7-0.92, p 0.001), low poverty index (HR = 1.12, 95% CI 0.98-1.12, p = 0.097), limited stage disease (HR = 3.12, 95% CI 2.66-3.66, p = <0.0001), and lack of air pollution exposure (HR = 1.09, 95% CI 0.95-1.24, p = 0.227). Multivariable PH analysis showed statistically significant OS improvement for those from lower poverty areas (HR = 1.22, 95% CI: 1.07- 1.4, p = 0.004) as well as in those without air pollution exposure (HR = 1.21, 95% CI: 1.05- 1.39, p = 0.008), controlling for age, sex, stage and smoking. Exposure to water pollution, violent crime rate, food desert designation and pack years smoked were not found to be independent predictors of OS. Conclusions: In this large detailed cohort of 982 patients with SCLC, there was a significantly lower OS for patients living in high poverty areas and for patients exposed to air pollutants. This effect was durable even after for controlling for age, sex, stage, and smoking status, demonstrating that these are independent risk factors associated with poorer OS. Our next research steps will be to examine the biologic basis for these disparities through genomic and transcriptomic analysis.