Effect of microvascular invasion on postoperative long-term prognosis of small and large hepatocellular carcinoma

Abstract

Objective To investigate the effect of microvascular invasion (MVI) on postoperative long-term prognosis of the patients with small and large hepatocellular carcinoma (HCC). Methods Clinical data of 549 patients who underwent radical hepatectomy in the Eastern Hepatobiliary Surgery Hospital of the Second Military Medical University between January 2008 and July 2008 were retrospectively analyzed. Among the patients, 467 cases were males and 82 females, 426 cases aged ≤60 years old and 123 aged >60 years old. According to the tumor diameter, the patients were divided into the small HCC group (tumor diameter ≤5 cm, n=319) and large HCC group (tumor diameter> 5 cm, n=230). The informed consents of all patients were obtained and the local ethical committee approval was received. Survival analysis was performed using Kaplan-Meier survival curve. Risk factors of postoperative long-term survival were analyzed using Cox proportional hazard regression model. Results In the small HCC group, the postoperative 1-, 3-, 5-year tumor-free survival rate and overall survival rate of the patients with MVI (-) was respectively 76%, 55%, 44% and 95%, 77%, 62%, significantly higher than 53%, 30%, 27% and 82%, 50%, 37% of the patients with MVI (+) (χ2=12.767, 18.937; P<0.05). In the large HCC group, the postoperative 1-, 3-, 5-year tumor-free survival rate and overall survival rate of the patients with MVI (-) was respectively 59%, 40%, 36% and 82%, 55%, 41%, significantly higher than 35%, 14%, 14% and 67%, 42%, 26% of the patients with MVI (+) (χ2=20.378, 9.733; P<0.05). Multivariate analysis indicated that, in the small HCC group, the tumor number, MVI and Edmondson-Steiner grade were the independent influence factors for postoperative tumor-free survival (HR=1.86, 1.46, 1.49; P<0.05), and CA19-9, MVI and Edmondson-Steiner grade were the independent influence factors for postoperative overall survival (HR=2.07, 1.85, 1.52; P<0.05). In the large HCC group, MVI and tumor diameter were the independent influence factors for postoperative tumor-free survival (HR=2.01, 1.05; P<0.05), and AFP, MVI and tumor diameter were the independent influence factors for postoperative overall survival (HR=1.75, 1.46, 1.06; P<0.05). Conclusion MVI is an independent risk factor for postoperative tumor-free survival and overall survival of patients with small and large HCC. Key words: Carcinoma Hepatocellular; Microvascular invasion; Survival rate; Risk factor; Prognosis