A new horizon in risk stratification of hepatocellular carcinoma by integrating vessels that encapsulate tumor clusters and microvascular invasion

Background Vessels that encapsulate tumor clusters (VETC) is a novel described vascular pattern different from microvascular invasion (MVI) for patients with hepatocellular carcinoma (HCC). The prognostic value of integrating VETC and MVI (VETC-MVI model) in HCC patients after resection remains unclear. Methods From January 2013 to December 2016, 498 HCC patients who underwent curative resection were enrolled from five academic centers and stratified into different groups according to their VETC and MVI statuses. Overall survival (OS), disease-free survival (DFS), and early and late recurrence rates were evaluated. Results The patients were divided into four subgroups: VETC-/MVI- (n = 277, 55.6%), VETC-/MVI+ (n = 110, 22.1%), VETC+/MVI- (n = 53, 10.6%), and VETC+/MVI+ (n = 58, 11.6%). The patients in the VETC+/MVI- and VETC-/MVI+ groups had similar long-term outcomes (OS: p = 0.402; DFS: p = 0.990), VETC-/MVI- patients showed the best prognosis, and VETC+/MVI+ patients had the worst prognosis. Further analysis revealed that the VETC-MVI model showed a similar stratification ability for early recurrence but not for late recurrence. The area under the curve values for early recurrence was 0.70, 0.63 and 0.64 for the VETC-MVI model, VETC, and MVI, respectively (VETC-MVI model vs VETC: p < 0.001; VETC-MVI model vs MVI: p = 0.004; VETC vs MVI: p = 0.539). Multivariate Cox regression analysis showed that the VETC-MVI model successfully predicted OS, DFS and early recurrence. Conclusions VETC status provides additional discriminative information for patients with either MVI- or MVI+. A combination of VETC and MVI may help classify subtypes and predict the prognosis of HCC patients.