Predictors for Microinvasion of Small Hepatocellular Carcinoma ≤2 cm

Hepatocellular carcinoma (HCC) a parts per thousand currency sign2 cm in diameter is considered to have a low potential for malignancy. A retrospective review was undertaken of 149 patients with primary solitary HCC a parts per thousand currency sign2 cm who underwent initial hepatic resection between 1994 and 2010. The independent predictors of the microinvasion (MI) such as portal venous, hepatic vein, or bile duct infiltration and/or intrahepatic metastasis were identified by multivariate analysis. Prognosis of patients with HCC a parts per thousand currency sign2 cm accompanied by MI was compared to that of patients with HCC a parts per thousand currency sign2 cm without MI. Forty-three patients with HCC a parts per thousand currency sign2 cm had MI in patients (28.9%). Three independent predictors of the MI were revealed: invasive gross type (simple nodular type with extranodular growth or confluent multinodular type), des-gamma-carboxy prothrombin (DCP) > 100 mAU/ml, and poorly differentiated. Disease-free survival rates of patients with HCC a parts per thousand currency sign2 cm with MI (3 year 44%) were significantly worse than those for HCC a parts per thousand currency sign2 cm without MI (3 year 72%). This disadvantage of disease-free survival rate of patients with HCC a parts per thousand currency sign2 cm with MI could be dissolved by hepatic resection with a wide tumor margin of a parts per thousand yen5 mm ( = 0.04). Even in cases of HCC a parts per thousand currency sign2 cm, patients who are suspected of having invasive gross type tumors in preoperative imaging diagnosis or who have a high DCP level (> 100 mAU/ml) are at risk for MI. Therefore, in such patients, hepatic resection with a wide tumor margin should be recommended.