Validation of the 7th Edition TNM Staging System for Hepatocellular Carcinoma: An Analysis of 8,828 Patients in a Single Medical Center

Background Major modification of the 7th tumor-node-metastasis (TNM) staging system for hepatocellular carcinoma (HCC) was divided into 6th stage IIIA to 7th IIIA (multiple tumors, any >5 cm) and IIIB (tumors involving a major vessel). This study aimed to validate 6th and 7th TNM systems in prognostic prediction, then analyze the impact of time, Child-Pugh classification and treatment modalities in survival. Methods A total of 5,611 and 3,217 HCC patients were enrolled between 1986-2002 (past period) and 2003-2010 (recent period), respectively. The Akaike information criteria (AIC) within a Cox proportional hazard regression model were used to demonstrate the discriminatory ability for staging systems. Results The 1-, 3-, and 5-year survival rates of past and recent periods were 44.8, 24.9, 17.1 %, and 65.5, 44.5, 34.6 %, respectively (p < 0.001). Rates of smaller HCC detection and received curative treatment were significantly higher in the recent period than in the past period (p < 0.001). Survival rates were different in each Child-Pugh class (all p < 0.001). Patients receiving curative treatment had highest survival rates, followed by non-curative treatment, and untreated patients (p < 0.05). In both periods, significant differences in survival curves existed between each of the stages in the 6th and 7th TNM staging (all p < 0.05), and also between IIIA and IIIB in the 7th TNM (p < 0.001). The AIC of two periods in the 6th and 7th TNM systems were decreased, with 77,895 and 77,630, and 19,162 and 19,135, respectively. Conclusion The 7th TNM provided better prognostic prediction than the 6th TNM after dividing into IIIA and IIIB. Survival rates of HCC have been improving in recent decades.