Background: According to the 7th AJCC TNM staging system, solitary hepatocellular carcinoma (HCC) is classified as T1 or T2 based on microvascular invasion (MVI) regardless of tumor size. This study intended to evaluate the prognostic impact of tumor size on survival outcomes after macroscopic curative resection of solitary HCC.
Methods: Patients who underwent R0 resection of solitary HCC <10 cm (n = 2558) were selected for study. Follow-up lasted ≥24 months or until death.
Results: HCC was detected during regular health screening or routine follow-up in 2054 cases (80.3%). Hepatitis B virus (HBV) infection was associated in 2127 (83.2%). Mean patient age was 54.4 ± 9.9 years. Anatomical resection was performed in 1786 (69.8%). MVI was identified in 407 (16.0%) which therefore became stage T2; the other 2150 became stage T1. Tumor recurrence and patient survival rates were 24.9 and 95.0% after 1 year, 49.6 and 84.1% after 3 years, 57.7 and 75.0 % after 5 years, and 67.3 and 56.6% after 10 years, respectively. Multivariate analysis showed that non-anatomical resection, MVI, and tumor size >5 cm were independent risk factors for both tumor recurrence and overall patient survival. Long-term survival correlated negatively with tumor size and MVI. Subgroup analysis with MVI and size cutoff of 5 cm revealed a significant survival difference (p = 0.000). Tumor size >5 cm was not a significant prognostic factor in non-HBV patients.
Conclusions: These results suggest that the prognostic impact of tumor size may be underestimated in the current version of the AJCC staging system and that solitary HCC staging could be improved with inclusion of tumor size cutoff of 5 cm in HBV-associated patients. Further validation is necessary with multicenter studies.