Background: The optimal follow-up strategy after curative thermal ablation of hepatocellular carcinoma (HCC) remains unclear.
Methods: We retrospectively analyzed a prospective series of 616 patients who underwent curative thermal ablation for HCC within the Milan criteria. Multivariate Cox model was used to identify independent predictive factors for recurrence; accordingly, patients were stratified into 2 groups with different relapse risks: a low-risk group (solitary tumor ≤3 cm) and a high-risk group (multiple tumors ≤3 cm or solitary tumor between 3 and 5 cm). Then, patients were classified into short- (< 4 months) or long-interval (4-6 months) surveillance groups according to follow-up intensity within the first 2 years after ablation. The overall survival (OS) of patients were compared between short- and long-interval groups in low- or high-risk groups, as well as the stage of recurrent tumors and the proportion of patients who received curative-intent retreatments.
Results: In the low-risk group, 54 (83.0%) and 18 (72.0%) of patients exhibited early relapse at the Barcelona Clinic Liver Cancer (BCLC) 0/A stage in the short- and long-interval groups, respectively (P = 0.172); accordingly, 44 (77.2%) and 18 (81.8%) of patients received curative-intent retreatment (P = 0.086) after recurrence. Hence, 5-year OS was similar between short- and long-interval groups (80.4% vs. 77.5%, P = 0.400) in low-risk patients. However, in the high-risk group, patients with a short interval exhibited early relapse more frequently at the BCLC 0/A stage (83% vs. 72%, P = 0.028), with a trend showing that the corresponding proportion of patients who received curative-intent retreatment greater than that in the long-interval group (64.2% vs. 37.5%, P = 0.087). Moreover, the short-interval group showed better 5-year OS than the long-interval group in high-risk patients (69.9% vs. 42.7%, P = 0.020).
Conclusions: Compared to a short surveillance interval, a long surveillance interval does not reduce OS in low-risk patients; however, a long surveillance interval compromises OS in high-risk patients.
Keywords: Liver cancer; Milan criteria; Overall survival; Recurrence-free survival; Surveillance; Thermal ablation.