Reappraisal of Portal Vein Tumor Thrombosis as a Prognostic Factor for Patients with Hepatocellular Carcinoma

Background/Aims: This study aimed to assess whether hepatocellular carcinoma (HCC) patients with portal vein tumor thrombosis (PVTT) could have favorable prognoses with proper treatment under selective conditions. Methods: This retrospective, single-center study involved 1,168 patients diagnosed with HCC between January 2005 and December 2006, before the introduction of sorafenib. Overall survival (OS) was estimated using the Kaplan-Meier method, and the Cox proportional hazards model was used to identify and adjust the variables associated with OS. Results: In nodular-type HCC, the OS differed significantly according to the presence of PVTT (log-rank p<0.001), and the level of PVTT, not only its presence, was a major independent factor affecting OS. PVTT at the Vp1-3 branch was associated with significantly longer OS than was PVTT at the Vp4 level (hazard ratio [HR], 1.82; 95% confidence interval [CI], 1.04 to 3.21). In multivariate analysis, the OS was further stratified according to the PVTT level and tumor type, representing that nodular HCC without PVTT exhibited the best OS, whereas nodular HCC with Vp4 PVTT (adjusted HR, 2.59; 95% CI, 1.57 to 4.28) showed a poor prognosis similar to that of infiltrative HCC. The PVTT level was consistently correlated with OS in patients treated with transarterial chemoembolization. Nodular HCC without PVTT showed the best prognosis, while nodular HCC with Vp1-3 PVTT also exhibited a favorable OS, although inferior to that without PVTT (adjusted HR, 1.47, 95% CI, 0.92 to 2.36). Conclusions: Active treatment such as transarterial chemoembolization can be considered for selected PVTT cases. The level of PVTT and type of HCC were independent prognostic factors.