Overall survival among patients who undergo resection does not differ significantly between T1a and T1b hepatocellular carcinoma based on the 8^th American Joint Commission on Cancer

Purpose: The 8th edition of the American Joint Committee on Cancer (AJCC) staging system for hepatocellular carcinoma (HCC) has been used since 2018. However, whether any significant difference in overall survival (OS) exists between patients with T1a and T1b HCC who undergo resection has been controversial. We aim to clarify this issue. Methods: We consecutively enrolled newly diagnosed HCC patients who underwent liver resection (LR) from 2010 to 2020 at our institution. OS was estimated using the Kaplan–Meier method and compared using log-rank tests. Prognostic factors for OS were identified by multivariate analysis. Results: This study enrolled 1250 newly diagnosed HCC patients who underwent LR. No significant differences in OS were identified between patients with T1a and T1b tumors among all patients (p = 0.694), cirrhotic patients (p = 0.753), non-cirrhotic patients (p = 0.146), patients with alpha-fetoprotein (AFP) > 20 ng/ml (p = 0.562), patients with AFP ≤ 20 ng/ml (p = 0.967), patients with Edmondson grade 1 or 2 (p = 0.615), patients with Edmondson grade 3 or 4 (p = 0.825), patients positive for hepatitis B surface antigen (HBsAg; p = 0.308), in patients positive for anti-hepatitis C virus (HCV) antibody (p = 0.781), or patients negative for both HBsAg and anti-HCV antibody (p = 0.125). Using T1a as the reference, multivariate analysis showed that T1b is not a significant predictive factor for OS (hazard ratio (HR): 1.338; 95% confidence interval (CI):0.737–2.431; p = 0.339). Conclusion: No significant difference in OS was observed between patients who underwent LR to treat T1a and T1b HCC tumors.