Markers for microvascular invasion in hepatocellular carcinoma: Where do we stand?

Abstract

It is well known that hepatocellular carcinoma (HCC) commonly involves the local branches of portal and/or hepatic veins and causes a tumor thrombus even at a relatively early stage. Vascular invasion is classified as macrovascular invasion, which is grossly recognizable (mostly in large to medium vessels), or microvascular invasion (MVI), which can be identified only by microscopic observation (mainly in small vessels such as portal vein branches in portal tracts, central veins in noncancerous liver tissue, and venous vessels in the tumor capsule and/or noncapsular fibrous septa).Although macroscopic vascular invasion in major vessels (and satellite nodules) is known to be a marker of poor outcomes after liver transplantation (LT) for HCC and is regarded as a contraindication for LT, the significance of MVI as a predictor of poor outcomes is still controversial. The controversy concerns the extent to which MVI (if it is identifiable before surgery) is a contraindication for LT, even though we know that only a minority of patients with MVI will experience HCC recurrence. MATERIALS AND METHODSWe searched the MEDLINE database (2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010) to determine the significance of MVI to the outcomes of LT for HCC; we used the keywords hepatocellular carcinoma, HCC, microvascular invasion, liver transplantation, and liver resection. We also performed a full manual search of the bibliographies of selected publications and included 4 additional publications from earlier years. Publications were included if they contained data on MVI and its relationship with tumor characteristics and/or prognostic data. The search resulted in a total of 48 relevant publications.The publications were then ranked according to the classification proposed by the Oxford Centre for Evidenced-Based Medicine.

Prediction of Microvascular Invasion of Hepatocellular Carcinoma: Preoperative CT and Histopathologic Correlation

“…Pathologic markers suggestive of an increased risk of microvascular invasion (MVI) include large tumor size, multiple tumors, intrahepatic micrometastasis, poor histologic grade, and gross anatomic subtype as defined by the Liver Cancer Study Group of Japan [5]. The three subtypes are defined as follows: a simple nodular type (a distinctly nodular tumor that frequently has a capsule); a simple nodular type with extranodular growth (a single nodular tumor with varying degrees of tumor growth beyond the tumor capsule); and a confluent multinodular type (a confluence of several minute to small nodules) [6][7][8][9][10].…”

MR–PET evaluation of 1-month post-ablation therapy for hepatocellular carcinoma: preliminary observations

“…Poor histological differentiation and the presence of vascular invasion increase the incidence of recurrence [12,13] and impacts on the prognosis. Although MRI is able to detect macrovascular invasion, microvascular invasion eludes detection [27][28][29][30]. PET may provide additional useful information, as prior studies have shown that increased FDG uptake in PET is predictive of microvascular invasion [14,15].…”

Liver Transplantation for HCC: A Review

“…Prominent among these are the presence of mVI, satellites, aneuploidy, and grade. Various studies have reported on the impact of tumor grade on pretransplant biopsy [58]. In a heterogeneous cohort including patients with tumors within and outside Milan criteria, those with well and moderately differentiated HCC had a 5-year actuarial DFS of 92% and OS of 75%, which was significantly better than those with poor differentiation.…”