Treatment Disparities Partially Mediate Socioeconomic- and Race/Ethnicity-Based Survival Disparities in Stage I-II Hepatocellular Carcinoma.

Background: Low socioeconomic status (SES) patients with early-stage hepatocellular carcinoma (HCC) receive procedural treatments less often and have shorter survival. Little is known about the extent to which these survival disparities result from treatment-related disparities versus other causal pathways. We aimed to estimate the proportion of SES-based survival disparities that are mediated by treatment- and facility-related factors among patients with stage I-II HCC.

Methods: We analyzed patients aged 18-75 years diagnosed with stage I-II HCC in 2008-2016 using the National Cancer Database. Inverse odds weighting mediation analysis was used to calculate the proportion mediated by three mediators: procedure type, facility volume, and facility procedural interventions offered. Intersectional analyses were performed to determine whether treatment disparities played a larger role in survival disparities among Black and Hispanic patients.

Results: Among 46,003 patients, 15.0% had low SES, 71.6% had middle SES, and 13.4% had high SES. Five-year overall survival was 46.9%, 39.9%, and 35.7% among high, middle, and low SES patients, respectively. Procedure type mediated 45.9% (95% confidence interval [CI] 31.1-60.7%) and 36.7% (95% CI 25.7-47.7%) of overall survival disparities for low and middle SES patients, respectively, which was more than was mediated by the two facility-level mediators. Procedure type mediated a larger proportion of survival disparities among low-middle SES Black (46.6-48.2%) and Hispanic patients (92.9-93.7%) than in White patients (29.5-29.7%).

Conclusions: SES-based disparities in use of procedural interventions mediate a large proportion of survival disparities, particularly among Black and Hispanic patients. Initiatives aimed at attenuating these treatment disparities should be pursued.