Integrating contrast-enhanced sonography in the follow-up algorithm of hepatocellular carcinoma treated with radiofrequency ablation: single cancer center experience

Abstract

Background: Hepatocellular carcinoma (HCC) patients treated with percutaneous ablation require close follow-up for early detecting and treating tumor recurrence.

Purpose: To illustrate our single-center prospective experience on using contrast-enhanced ultrasound (CEUS) as a follow-up tool alternated with computed tomography (CT).

Material and methods: In a 7-year period 588 patients with one to three HCCs were treated with radiofrequency ablation (alone or combined with ethanol injection). Patients with completely ablated tumors at 1-month CT scan were followed up serially, using alternated CEUS (one microbubbles injection per lobe) and CT every 3 months for 2 years. In few cases magnetic resonance imaging (MRI) was employed instead of or in addition to CT. The following patterns of recurrence were considered: A, enhancing tissue within the lesion; B, enhancing tissue adherent to the lesion; C, enhancing tissue within the same liver segment of the treated nodule; and D, enhancing tissue within a different segment. Patients with positive CEUS underwent confirmatory CT/MRI (standard reference).

Results: Median follow-up was 19 months. There were 221 recurrences. Three pattern A recurrences (2 detected by CEUS and 1 by CT), 86 pattern B recurrences (44 detected by CEUS and 42 by CT), 70 pattern C recurrences (32 detected by CEUS and 38 by CT), and 62 pattern D recurrences (23 detected by CEUS and 39 by CT). CT detected additional nodules in 16/101 patients with positive CEUS.

Conclusion: CEUS follow-up of HCC patients after ablation is feasible. Since 72% recurrences develop in the same segment of the necrotic nodule, CEUS proves to be effective despite the minor visualization of the entire liver during the arterial phase when compared to CT and MRI. Including CEUS in patient follow-up may reduce the number of CT and MRI examinations.

Keywords: Hepatocellular carcinoma; contrast-enhanced sonography; follow-up strategy; radiofrequency ablation; tumor recurrence.