Prognostic value of a novel risk classification of microvascular invasion in patients with hepatocellular carcinoma after resection

OBJECTIVES The present research aimed to evaluate the prognostic value of a novel risk classification of microvascular invasion (MVI) in hepatocellular carcinoma (HCC) after resection. METHODS A total of 295 consecutive HCC patients underwent hepatectomy were included in our study. We evaluated the degree of MVI according to the following three features: the number of invaded microvessels (≤5 vs >5), the number of invading carcinoma cells (≤ 50 vs >50), the distance of invasion from tumor edge (≤1 cm vs >1 cm). RESULTS All patients were divided into three groups according to the three risk factors of MVI: non-MVI group (n=180), low-MVI group (n=60) and high-MVI group (n=55). The overall survival (OS) and recurrence-free survival (RFS) rates of high-MVI group were significantly poorer than those of low-MVI and non-MVI groups (P<0.001 and P=0.001; P<0.001 and P=0.003). Multivariate analysis showed high-MVI, type of resection, ICG-R15 and tumor size were risk factors for OS after hepatectomy. High-MVI, type of resection and tumor size were risk factors for RFS. In subgroup analyses, the OS and RFS rates of low-MVI and non-MVI groups were better than high-MVI group regardless of tumor size. In high-MVI group, anatomical liver resection (n=28) showed better OS and RFS rates compared with non-anatomical liver resection (n=29) (P=0.012 and P=0.002). CONCLUSIONS The novel risk classification of MVI based on histopathological features is valuable for predicting prognosis of HCC patients after hepatectomy.