Effect of microvascular invasion on the postoperative long-term prognosis of solitary small HCC: a systematic review and meta-analysis

Abstract Background The effect of microvascular invasion (MVI) on the postoperative long-term prognosis of solitary small hepatocellular carcinoma remains controversial. We compared the long-term outcomes of MVI-positive and MVI-negative groups of patients with solitary small hepatocellular carcinoma. Methods The PubMed, EMBASE, Cochrane Library, VIP, Wan Fang, and Sino Med databases were systematically searched to compare the long-term outcomes of MVI-positive and MVI-negative groups of patients with solitary small hepatocellular carcinoma from inception to November 1, 2018. The study outcomes, including overall survival (OS) and disease-free survival (DFS), were extracted independently by two authors. Results Fourteen studies involving 3033 patients were evaluated. A meta-analysis of all 14 studies suggested that the OS of the MVI-positive group was significantly worse than that of the MVI-negative group (HR = 2.39, 95% CI = 2.02–2.84, I 2  = 22.8%; P  2  = 25.3%; P  Conclusion Microvascular invasion was a risk factor for poorer prognosis for solitary small hepatocellular carcinoma.