A New Staging System for Hepatocellular Carcinoma Associated with Portal Vein Tumor Thrombus

Background. BCLC C stage does not identify patients homogeneous enough to be allocated to a single stage. A new staging system for patients with hepatocellular carcinoma (HCC) associated with portal vein tumor thrombus (PVTT) was developed by incorporating the good points of the BCLC classification of HCC, and by improving on the currently existing classifications of HCC with PVTT. Methods. Univariate and multivariate analysis with Wald χ2 test were used to determinate the clinical prognostic factors for overall survival (OS) in patients with HCC and PVTT in the training cohort. Then the conditional inference trees analysis was applied to establish a new staging system. Results. A training cohort of 2179 patients from the Eastern Hepatobiliary Surgery Hospital and a validation cohort of 1550 patients from four major liver centers in China were enrolled into establishing and validating a new staging system. The system was established by incorporating liver function, general health status, tumor resectability, extrahepatic metastasis and extent of PVTT. The median OS were 57.1 (37.2-76.9), 12.1 (11.0-13.2), 5.7 (5.1-6.2), 4.0 (3.3-4.6) and 2.5 (1.7-3.3) months for the stages 0 to IV, respectively (p<0.001) in the Training Cohort. The corresponding figures for the validation cohort were 37.6 (35.9-39.2) and 30.4 (27.4-33.4), 6.4 (4.9-7.9), 2.8 (1.3-4.4), and 1.5 (1.3-1.7) months for the stages 0 to IV, respectively (P<0.001). Conclusions. A new staging system was established which provided a good discriminatory ability to separate patients into different stages and substages after treatments. It can be used to supplement the other HCC staging systems. Funding: This work was supported by the grants of the National Science Foundation for Young Scientists of China (Grant No.81602523). The Science Fund for Creative Research Groups (No: 81221061); The National Key Basic Research Program 973 project (No: 2015CB554000); the China National Funds for Distinguished Young Scientists (No: 81125018). Declaration of Interest: There are no further declaration on financial disclosures, conflicts of interest, and/or acknowledgements to make. Ethical Approval: The study was approved by the Ethics Committees of all the five hospitals.