Development and Validation of Insulin-like Growth Factor-1 Score to Assess Hepatic Reserve in Hepatocellular Carcinoma

BACKGROUND Child-Turcotte-Pugh (CTP) score is the standard tool to assess hepatic reserve in hepatocellular carcinoma (HCC), and CTP-A is the classic group for active therapy. However, CTP stratification accuracy has been questioned. We hypothesized that plasma insulin-like growth factor 1 (IGF-1) is a valid surrogate for hepatic reserve to replace the subjective parameters in CTP score to improve its prognostic accuracy. METHODS We retrospectively tested plasma IGF-1 levels in the training set (n = 310) from MD Anderson Cancer Center. Recursive partitioning identified three optimal IGF-1 ranges that correlated with overall survival (OS): greater than 50 ng/mL = 1 point; 26 to 50 ng/mL = 2 points; and less than 26 ng/mL = 3 points. We modified the CTP score by replacing ascites and encephalopathy grading with plasma IGF-1 value (IGF-CTP) and subjected both scores to log-rank analysis. Harrell's C-index and U-statistics were used to compare the prognostic performance of both scores in both the training and validation cohorts (n = 155). All statistical tests were two-sided. RESULTS Patients' stratification was statistically significantly stronger for IGF-CTP than CTP score for the training (P = .003) and the validation cohort (P = .005). Patients reclassified by IGF-CTP relative to their original CTP score were better stratified by their new risk groups. Most important, patients classified as A by CTP but B by IGF-CTP had statistically significantly worse OS than those who remained under class A by IGF-CTP in both cohorts (P = .03 and P < .001, respectively, from Cox regression models). AB patients had a worse OS than AA patients in both the training and validation set (hazard ratio [HR] = 1.45, 95% confidence interval [CI] = 1.03 to 2.04, P = .03; HR = 2.83, 95% CI = 1.65 to 4.85, P < .001, respectively). CONCLUSIONS The IGF-CTP score is simple, blood-based, and cost-effective, stratified HCC better than CTP score, and validated well on two independent cohorts. International validation studies are warranted.