Predictor for Histological Microvascular Invasion of Hepatocellular Carcinoma: A Lesson from 229 Consecutive Cases of Curative Liver Resection

Background Microscopic vascular invasion is an important risk factor for recurrent hepatocellular carcinoma (HCC), even after curative liver resection or orthotopic liver transplantation. To predict microscopic portal venous invasion, the following two questions were examined retrospectively: Is it possible to detect microvascular invasion preoperatively? What are the characteristics of a group of early HCC recurrences even with no microvascular invasion? Methods Study 1 included 229 patients with HCC who underwent curative liver resection between 1991 and 2008; 127 had HCC without microscopic portal venous invasion, and 52 had HCC with microscopic portal venous invasion (MPVI). These two distinct groups were analyzed with regard to various clinicopathologic factors. Subsequently, we specifically investigated if HCCs <5 cm with vascular invasion ( n = 32) have some characteristics that would allow detection of latent microvascular invasion. Study 2 included 127 HCC patients without MVPI; 42 had a recurrence within 2 years, and 85 patients were recurrence‐free for at least 2 years. These two distinct groups were analyzed with regard to various clinicopathologic factors. Results HCC diameter of >5 cm, the macroscopic appearance of HCC, and high levels of preoperative des‐γ‐carboxyprothrombin are significant prognostic factors in identifying microvascular invasion of HCC. The strongest predictor of early recurrence (within 2 years) was the serum α‐fetoprotein level in patients without clear microvascular invasion. Conclusions Tumor size, macroscopic appearance, and high tumor marker levels are important elements in identifying the group of patients with a low HCC recurrence rate after curative liver resection.