Tumor Size Drives the Prognosis After Hepatic Resection of Solitary Hepatocellular Carcinoma Without Vascular Invasion

Purpose We assessed the association of tumor size with patient survival following diagnosis of solitary hepatocellular carcinoma without vascular invasion. Methods The overall population comprised 638 patients who initially underwent hepatic resection with curative intent for a solitary hepatocellular carcinoma without macroscopic vascular invasion (487 had no microscopic vascular invasion). We set 5 cm as the tumor cutoff size for a solitary tumor based on the Milan criteria, and we used a multivariate Cox proportional hazards model and propensity score matching to evaluate the impact of tumor size on survival. Results Tumor size was significantly associated with a proportional increase in cancer-specific survival in the overall population (P = 0.001) and the subgroup with no microscopic vascular invasion (P = 0.029); however, multivariate analysis revealed no significant risk associated with recurrence-free survival (P = 0.055 and 0.59, respectively). After propensity score matching, the cancer-specific survival of patients with tumors > 5 cm was significantly worse than for those with tumors <= 5 cm in the overall population (P = 0.0077); the corresponding 2-year cumulative recurrence rates were 45.8% and 23.5%, respectively (P = 0.0027). Finally, the proportions of extrahepatic to total recurrences were 8% for those with tumors <= 5 cm and 29.1% for those with tumors > 5 cm in the unmatched overall population (P < 0.001). Conclusion Tumor size was associated with recurrence within 2 years of surgery and with poor cancer-specific survival in patients with solitary hepatocellular carcinoma, even in the absence of microscopic vascular invasion.