Utility of scoring systems combining the product of tumor number and size with liver function for predicting the prognosis of patients with hepatocellular carcinoma after hepatectomy.

Our previous study reported the effectiveness of the product of tumor number and size (NxS factor) as a predictor of the prognosis of patients with hepatocellular carcinoma (HCC) following hepatectomy. The aim of the present study was to validate the prognostic value of scoring systems based on the NxS factor for HCC. The records of 940 patients who underwent hepatectomy for HCC at Osaka University Graduate School of Medicine and Osaka International Cancer Institute were analyzed. The discriminatory abilities of the mathematical integrated model for tumor staging (MITS) score, which combines the NxS factor with liver function, and known prognostic systems, including the Japan Integrated Staging system, the Barcelona Clinic Liver Cancer, Cancer of the Liver Italian Program and the Tokyo system, were compared. Firstly, the present study demonstrated that a higher NxS factor was associated with decreased disease-free survival (DFS) and overall survival (OS) in patients with HCC (P<0.05). Subsequently, univariate analysis of DFS and OS curves revealed significant differences among all NxS factor and liver damage combinations (MITS-LD score; score 0 vs. score 1; score 1 vs. score 2; score 2 vs. score 3; all P<0.05) and all NxS factor and albumin-bilirubin (ALBI) score combinations (MITS-ALBI score; score 0 vs. score 1; score 1 vs. score 2; score 2 vs. score 3; all P<0.05). Furthermore, multivariate Cox proportional hazards model analysis demonstrated that there were significant differences in DFS [Hazard Ratio (HR); score 0 vs. score 1 (1.48); score 1 vs. score 2 (1.27); score 2 vs. score 3 (1.64); all P<0.05] and OS [HR; score 0 vs. score 1 (1.34); score 1 vs. score 2 (1.29); score 2 vs. score 3 (1.64); all P<0.05] among patients with different MITS-LD scores, and there were significant differences in DFS [HR; score 0 vs. score 1 (1.38); score 1 vs. score 2 (1.43); score 2 vs. score 3 (1.60); all P<0.05] among patients with different MITS-ALBI scores. The NxS factor may be a comprehensive measure of tumor burden for predicting the prognosis of patients with HCC following liver resection, and MITS scores could be an improved scoring system for predicting the prognosis of patients with HCC after hepatectomy.