Incidence of new foci of hepatocellular carcinoma after radiofrequency ablation: role of multidetector CT

Purpose. The authors sought to assess the incidence of new foci of hepatocellular carcinoma (HCC) using multidetector computed tomography (MDCT) in patients treated with radiofrequency ablation (RFA). Materials and methods. Two readers retrospectively reviewed by consensus the follow-up MDCT studies of 125 patients (88 men and 37 women; mean age 68 years) with 141 HCCs (size 1–5.2 cm; mean 2.2 cm) treated with RFA. MDCT follow-up was performed at 1 and 3 months and every 6–12 months thereafter. Reviewers assessed: (1) the presence of new HCC foci in the same liver segment or in a different segment; (2) complete or incomplete tumor ablation; (3) tumour progression. Results. A total of 113 new HCCs (size 0.7–4.8 cm; mean 1.7 cm) were detected in 69/125 (55.2%) patients (mean follow-up 30.38±19.14 months). Of these, 86 (76.1%) new HCCs were multiple (p<0.0001), and 92 (81.4%) occurred in a different segment from that of the treated HCC (p<0.0001). New HCCs were observed in the first 12 months, between 12 and 24 months and after 24 months in 31/69 (44.9%), 24/69 (34.8%) and 14/69 (20.3%) patients, respectively (p=0.175). Mean diseasefree interval was 16.1±16.31 (range 1–52) months. Complete tumour ablation was achieved in 132/141 (93.6%) treated HCCs, and tumour progression occurred in 29/141 (20.6%) cases. Conclusions. In patients with RFA-treated HCCs, MDCT follow-up revealed a high incidence of new HCCs, even after 1 year of follow-up. The new foci tended to be multiple and located in a liver segment different from that of the previously treated nodules.