The Effect of Microvascular Invasion on Hepatocellular Carcinoma With Portal Vein Tumor Thrombus After Hepatectomy: A Retrospective Study.

Background: There is no report resolving whether microvascular invasion (MVI) affects the prognosis of hepatectomy for hepatocellular carcinoma (HCC) patients with portal vein tumor thrombus (PVTT). The present study aimed to investigate the effect of MVI on HCC with PVTT after hepatectomy.

Methods: 362 HCC patients with PVTT were included in this retrospective study. Diagnostic criteria of PVTT in HCC patients were based on typical preoperative radiological features on imaging studies. The log-rank test was utilized to differentiate overall survival (OS) and recurrence-free survival (RFS) rates between the two groups. Univariate and multivariate Cox proportional hazard regression was utilized to detect independent factors.

Results: PVTT without MVI accounted for 12.2% (n = 44). PVTT without MVI groups was significantly superior to PVTT with MVI groups in OS (the median survival = 27.1 months vs 13.7 months) and RFS (the median survival = 6.4 months vs 4.1 months). The 1-, 3-, and 5-year OS rates (65.5%, 36.8%, 21.7% vs 53.5%, 18.7%, 10.1%, P = .014) and RFS rates (47.0%, 29.7%, 19.2% vs 28.7%, 12.2%, 6.9%, P = .005) were significant different between two groups. Multivariate analysis showed that MVI was an independent risk factor for OS (hazard ratio (HR) = 1.482; P-value = .045) and RFS (HR = 1.601; P-value = .009).

Conclusions: MVI was an independent prognostic factor closely linked to tumor recurrence and poorer clinical outcomes for HCC patients with PVTT after hepatectomy. MVI should be included in current PVTT systems to supplement to the PVTT type.