Subclassification of patients with solitary hepatocellular carcinoma based on post-hepatectomy survival: a large retrospective study.

Official guidelines group together all cases of solitary hepatocellular carcinoma (HCC) without macroscopic vascular invasion, regardless of tumor size. Here, we examined whether this is justified based on overall survival (OS) after hepatic resection (HR). Patients with newly diagnosed solitary HCC treated by initial HR from January 2004 to October 2013 were classified into six groups based on tumor size (in 2-cm increments). Combining adjacent categories with similar OS led to three groups: ≤5 cm (n = 426), >5 and ≤8 cm (n = 229), and >8 cm (n = 202). Among all patients, median survival time was 62 months, and OS was 95 % at 1 year, 73 % at 3 years, and 54 % at 5 years. Patients in the ≤5 cm group showed significantly higher OS (P < 0.001) and lower tumor recurrence (P = 0.004) than those in the >5 and ≤8 cm group, who in turn showed significantly higher OS (P = 0.003) and lower tumor recurrence (P = 0.021) than those in the >8 cm group. Our results suggest that patients with solitary HCC should be subclassified based on tumor size for more accurate prognosis. We propose defining solitary HCC tumors >5 and ≤8 cm as "large" and tumors >8 cm as "huge".