Dynamic changes in the characteristics of hepatocellular carcinoma among Japanese patients: Increasing incidence of cases without liver fibrosis.

Aim: Dynamic changes in the characteristics of hepatocellular carcinoma (HCC) have been observed owing to the development of antiviral therapies and an aging society. This study aimed to evaluate the clinical features and prognosis of patients with HCC but without liver fibrosis (F0 HCC).

Methods: From 2000 to 2023, 505 patients with HCC who underwent surgical resection as an initial treatment were enrolled and categorized into the F0 (n = 59) and fibrosis (F1-4, n = 446) groups based on their liver fibrosis status. Clinical features, tumor factors, and survival outcomes were retrospectively analyzed. Inverse probability weighting with propensity scores was used to control for baseline differences between the groups.

Results: The proportion of F0 HCC (G1/G2/G3/G4 = 1.3/7.0/13.3/20.0%, p < 0.001) and nonviral (NBNC) HCC cases increased steadily over the study period. Patients in the F0 group were older and more likely to show solitary giant tumors; however, no significant differences were observed in tumor differentiation, microvascular invasion, or intrahepatic metastasis between the groups. After adjusting for baseline characteristics, the F0 group showed significantly improved overall survival and recurrence-free survival compared to the fibrosis group (adjusted median OS: not achieved vs. 90.6 months, p < 0.001; adjusted median RFS: 67.2 vs. 35.1 months, p < 0.001).

Conclusions: The increasing prevalence of NBNC HCC has contributed to an increase in the number of F0 HCC cases, demonstrating favorable prognoses post-curative treatment. Screening strategies tailored to detect F0 HCC are urgently needed to optimize outcomes, particularly for older patients and those with large tumors.