Abstract D132: The association between Insurance and lung cancer survival: The relative contributions of sociodemographic, tumor, treatment, and neighborhood factors

Health insurance is associated with lung cancer treatment and survival. It remains unclear to what extent insurance-associated survival disparities are attributed to prognostic factors of lung cancer. Using the Surveillance, Epidemiology, and End Results dataset, we identified 127,784 patients (age<65) diagnosed with lung cancer between 2007 and 2016. Cox proportional hazards regression was used to compute hazard ratios (HRs) of lung cancer-specific mortality. Relative contributions of prognostic factors to survival disparities were quantified by percent changes in HRs with sequential adjustment for marital status, socioeconomic deprivation, rurality, cancer stage, size, histology, surgery, radiation therapy, and chemotherapy. Difference in differences analysis was performed to examine the associations between Medicaid expansion and changes in proportions of no insurance and early-stage diagnosis, and 2-year survival rates. Compared with privately insured counterparts, the risk of cancer-specific mortality was significantly increased in uninsured men (HR=1.51, 95% CI 1.47-1.56; 5-year absolute risk difference (ARD)=12.5%, 95% CI 11.6%-13.3%) in uninsured men, Medicaid men (HR=1.36, 95% CI 1.33-1.39; 5-year ARD=9.6%, 95% CI 9.0%-10.3%), uninsured women (HR=1.66, 95% CI 1.59-1.72; 5-year ARD=17.0%, 95% CI 15.8%-18.2%), and Medicaid women (HR=1.41, 95% CI 1.38-1.45; 5-year ARD=12.0%, 95% CI 11.2%-12.9%) after adjustment for age, race, and registries. Further adjustment for the aforementioned factors explained 63.7%-70.6% of survival disparities. Medicaid expansion was associated with a greater reduction in uninsured rates (2.0 percentage point (ppt), p<.0001), and a greater increase in the proportion of early-stage diagnosis (2.1 ppt, p<0.01) and 2-year survival (1.3 ppt, p=0.04) in men only, after adjustment for covariates. The study provided evidence for worse survival in uninsured and Medicaid lung cancer patients compared with privately insured counterparts, more than half of which were attributable to sociodemographic, tumor, treatment, and neighborhood factors. Medicaid expansion was associated with shift towards early-stage diagnosis and improvements in short-term survival in men with lung cancer.

Citation Format: Ying Liu, Min Lian, Graham Colditz. The association between Insurance and lung cancer survival: The relative contributions of sociodemographic, tumor, treatment, and neighborhood factors [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr D132.