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.