Outcomes and predictors of microvascular invasion of solitary hepatocellular carcinoma

Aim: Microvascular invasion (MVI) is an important risk factor for early recurrence of hepatocellular carcinoma (HCC), but preoperative prediction of MVI is difficult. Methods: A retrospective review was undertaken on 167 patients with primary solitary HCC who underwent initial hepatectomy. Independent predictors of MVI were identified, and factors affecting disease-free survival in patients with MVI were clarified. Results: Of the 167 patients, 20 patients (12%) had MVI. Recurrence rates of HCC after hepatectomy in MVI patients were significantly worse than in patients without MVI (P < 0.0361). Univariate analysis revealed that positive L3-AFP, PIVKA-II >= 150 mAU/mL and tumor size >= 3 cm preoperatively were associated with positive MVI. On multivariate analysis, independent predictors of MVI were PIVKA-II >= 150 mAU/mL (odds ratio [OR], 5.19; 95% confidence interval [95% CI], 1.44-24.87; P = 0.0109) and positive L3-AFP (OR, 3.47; 95% CI, 1.19-10.75; P = 0.0229). Among the MVI-positive group, the 1-, 2- and 3-year disease-free survival rates were 78%, 58%, and 58% in patients with surgical margin (SM) >= 10 mm and 38%, 29%, and 29% in those with SM < 10 mm, respectively (P = 0.0263). Conclusions: Patients with PIVKA-II >= 150 mAU/mL and positive L3-AFP on preoperative examination are at high risk for MVI.