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.