BACKGROUND: The optimal strategy for dealing with sub-centimeter hepatic nodules has not yet been established. This study aimed to assess whether there was a need to provide curative treatments for sub-centimeter hepatocellular carcinomas (HCCs) to patients at risk for high false positives.

MATERIAL AND METHODS: We identified patients with primary pathologically diagnosed HCC ≤2 cm from 2004 to 2015 in the Surveillance, Epidemiology and End Results (SEER) database. They were divided according to the interventions they received: local ablation, surgical resection, or liver transplantation. In each group, overall survival and cancer-specific survival were used as endpoints to compare the prognoses between patients with sub-centimeter HCC and patients with HCC measuring 1 to 2 cm by Kaplan-Meier. Propensity score matching was performed to reduce bias. We also compared the survival of patients with a primary solitary HCC based on interventions, in the different tumor size groups. Bootstrapping was performed to validate the findings.

RESULTS: Overall, 10.4% of patients (197 out of 1894) had HCCs <1 cm, and 89.6% of patients (1697 out of 1894) had HCCs in the 1 to 2 cm range. There was no significant difference in overall and cancer-specific survival between patients with HCCs <1 cm and those with HCCs in the 1 to 2 cm range, in all treatment groups. After adjusting confounding factors, no significant correlation was found between tumor size and survival time. In patients with HCCs measuring ≤2 cm, overall survival and cancer-specific survival were superior in liver transplantation compared with surgical resection and local ablation. Surgical resection provided better survival than local ablation.

CONCLUSIONS: Compared to patients with HCCs measuring 1 to 2 cm, the survival rates of patients with sub-centimeter HCCs was not improved through curative treatments, risking high false positives.

Keywords: Carcinoma, Hepatocellular, SEER Program, Follow-Up Studies, Hepatectomy, Liver Neoplasms, propensity score, Survival Rate