Supplementary Material for: Development of a Novel Inflammation-Based Index for Hepatocellular Carcinoma

<b><i>Background:</i></b> The aim of current study was to (1) construct and validate a novel hepatocellular carcinoma (HCC)-specific inflammatory index; (2) compare the performances of the Integrated Liver Inflammatory Score (ILIS) to existing 4 inflammatory indices in HCC; (3) explore the association between the inflammatory indices and systemic/intratumoral inflammatory markers. <b><i>Methods:</i></b> Two cohorts from Hong Kong (HK; <i>n</i> = 1,315) and Newcastle (<i>n</i> = 574) were studied. A novel index was constructed from the HK training set (<i>n</i> = 627). The index was constructed from the training set by combing independent prognostic circulating parameters, followed by validating in the validation set of HK cohort (<i>n</i> = 688) and the Newcastle cohort. Its prognostic performance was compared to 4 inflammatory indices, namely, the neutrophil to lymphocyte ratio, platelet-to-lymphocyte ratio, prognostic nutrition index, and systemic immune-inflammation index, were compared in the HK cohort. Circulating cytokines and intratumoral gene expression were analyzed in a subset of patients with available samples and correlated with the inflammatory indices. <b><i>Results:</i></b> In the training set of the HK cohort, the ILIS, was generated: –0.057 × albumin (g/L) + 0.978 × log (Bilirubin, µmol/L) + 1.341 × log (alkaline phosphatase, IU/L) + 0.086 × Neutrophil (10⁹/L) + 0.301 × log (alpha-fetoprotein, µg/L). With cutoff of 2.60 and 3.87, the ILIS could categorize patients into 3 risk groups in the both validation cohorts. ILIS outperforms other inflammatory indices and remains an independent prognosticator for overall survival after adjustment with Barcelona Clinic Liver Cancer (hazard ratio 31.90, <i>p</i> &lt; 0.001). The ILIS had the best prognostic performances as compared to other inflammatory indices. In exploratory analyses, the ILIS correlated with circulating inflammatory cytokines (e.g., IL-8) but not with any intratumoral inflammatory gene expression. <b><i>Conclusions:</i></b> ILIS is an HCC-specific prognostic index built on 5 readily available blood parameters. Its versatility is validated both Eastern and Western population of HCC. The score is correlated with levels of circulating cytokines.