Ablative margin assessment for recurrence prediction in patients with hepatocellular carcinoma receiving radiofrequency ablation.

Abstract

Background/purpose: To predict outcomes for patients with hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA) by assessing the ablative margin.

Methods: We retrospectively analyzed 163 HCC patients with complete RFA treatment at National Taiwan University Hospital (NTUH) from 2015 to 2020. Local tumor progression (LTP) is defined as the reappearance of HCC around the ablative zone. Various ablative margins (AM) are measured on post-RFA computed tomography (CT), including the minimal and maximal AM covering or not covering the liver surfaces (AMCLSmin, AMCLSmax, AMULSmin, AMULSmax). Average ablative margins (AMCLSavg, AMULSavg) are calculated from the minimal and maximal AM. Tumors at high-risk locations, including subdiaphragmatic, subcapsular, and perivascular regions, were further analyzed. The Kaplan-Meier method was utilized to analyze the recurrence-free survival (RFS) of different groups of patients. Patients were grouped by their ablative margin width with a cutting-off value of 3 mm or 5 mm.

Results: Of the 163 HCC patients enrolled, 29 had LTP within two years, and 20 had LTP after two years. AMULSmin and AMULSavg were shown to be significant factors contributing to local tumor recurrences. Patients with AMULSmin≧3 mm had significantly better RFS than those with AMULSmin<3 mm (p = 0.0236). In high-risk locations, AMULSavg ≧5 mm had better RFS in subdiaphragmatic and subcapsular regions, and AMULSavg ≧3 mm had better RFS in perivascular region.

Conclusion: Measuring the ablative margin without covering the liver surface (especially AMULSmin, AMULSavg) in the post-RFA CT may be helpful prognosis indicators of LTP and RFS in HCC patients.