Young patients with hepatocellular carcinoma beyond Milan criteria had higher early recurrence and poorer long-term outcomes after hepatectomy.

BACKGROUND: Hepatocellular carcinoma (HCC) in young patients is uncommon, and their postoperative prognosis remains poorly defined. This study aimed to evaluate the impact of young age on tumor characteristics, recurrence, and long-term outcomes after hepatectomy in patients with HCC. METHODS: We reviewed 5465 patients who underwent curative-intent hepatectomy for HCC at Asan Medical Center between December 2008 and March 2019. Patients were categorized into younger (< 40 years, n = 265) and older (≥ 40 years, n = 5200) groups. Clinicopathological characteristics, recurrence rates, overall survival (OS), and recurrence-free survival (RFS) were compared between groups before and after 1:10 propensity score matching (PSM). Multivariate logistic regression analysis was performed to identify independent predictors of 2-year recurrence. RESULTS: Younger patients were more likely to have hepatitis B virus-related HCC (81.1% vs. 65.3%, P < 0.001) and a lower prevalence of cirrhosis (38.5% vs. 45.9%, P = 0.018), and they exhibited a higher 2-year recurrence rate than older patients (39.6% vs. 31.7%, P = 0.007). Among patients within Milan criteria, younger patients showed superior OS (P = 0.028) and RFS (P = 0.013). In contrast, among patients beyond Milan criteria, younger patients had significantly poorer OS (P < 0.001) and RFS (P = 0.003) compared with older patients. These patterns persisted after PSM. Multivariate analysis identified age < 40 years as an independent predictor of 2-year recurrence in the beyond Milan criteria group, but not in the within Milan criteria group. CONCLUSIONS: Young patients with HCC, particularly those beyond Milan criteria, were at increased risk of early recurrence and poorer long-term outcomes. These findings support the need for closer surveillance and tailored treatment strategies in this population.