Factors associated with favorable survival outcomes for Asians with hepatocellular carcinoma: A sequential matching cohort study

BACKGROUND: Overall 5-year survival rates for patients diagnosed with hepatocellular carcinoma (HCC) are poor, but vary by race/ethnicity. We undertook a comprehensive assessment of underlying contributing factors to the favorable survival outcomes of HCC among Asians compared with non-Hispanic whites (NHW). METHODS: We identified 1,284 Asian and 7,072 NHW patients newly diagnosed with HCC between 1994 and 2011 in the Surveillance, Epidemiology and End Results (SEER)-Medicare linked database. We used a novel three-step sequential matching approach to identify demographic, presentation and treatment factors that may explain survival differences between Asians and NHWs. Hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) for the association between Asian race and risk of HCC-related mortality were estimated using Cox proportional hazards models. RESULTS: The absolute difference in 5-year survival rates between Asians and NHWs was 8.4% (95% CI: 4.6%-12.0%) in the demographics match analysis. The disparity remained unchanged after additionally matching on stage, grade and comorbidities in the presentation match analysis. However, in the treatment match analysis, which accounts for differences in demographic, presentation and treatment factors, the absolute difference in 5-year survival rates was reduced to 5.8% (95% CI: 2.6%-9.3%). Treatment differences explained more of survival disparity in Asian and NHW patients with localized disease than for those with regional or distant stage HCC. CONCLUSIONS: Asian patients with HCC continue to have more favorable survival outcomes than NHWs with HCC. This persistent disparity seems to be more related to treatment differences than to differences in presentation characteristics including stage.