A modified TNM-7 staging system to better predict the survival in patients with hepatocellular carcinoma after hepatectomy

Abstract

To evaluate the accuracy of the 7th edition of the American Joint Committee on Cancer staging system (TNM-7) for patients undergoing hepatectomy for hepatocellular carcinoma (HCC) and to propose a modified TNM system for better prediction of survival. Clinico-pathological data for 1,313 patients who underwent hepatectomy as initial treatment for HCC between 2000 and 2008 were retrieved from a prospective database. Overall survival (OS) and disease-free survival (DFS) were analyzed to evaluate the predictive value. The 1-, 3-, 5-year OS and DFS of 1,313 patients were 79.2, 55.4, 45.5 %, and 52.6, 36.1, 31.8 %, respectively. Multivariate analysis revealed that major vascular invasion was the most important prognostic factor for both OS and DFS, along with tumour number and size. Patients with pT1 and pT2 disease had significantly better OS and DFS than those with pT3 disease (P < 0.001). There was no significant difference between pT3a and pT4 (P = 0.552) but patients with pT3b disease had a worse OS and DFS than those with pT4 disease (P = 0.006 and P < 0.001, respectively). A modified TNM system within the existing framework was proposed to combine the current pT3a and pT4 together as the new pT3 and to change pT3b to the new pT4. Analysis showed that this modified system had a better prognostic power than either TNM-6 or TNM-7. TNM-7 would seem to be inaccurate for staging advanced HCC. The modified system can improve both the prognostic accuracy and the hazard discrimination of disease to be consistent among subgroups of HCC.