Assessment of Radiofrequency Ablation Efficacy for Hepatocellular Carcinoma by Histology and Pretransplant Radiology

Abstract

Radiofrequency ablation (RFA) represents a potentially curative option for early‐stage hepatocellular carcinoma (HCC). This study aims at evaluating the histologic response after RFA of small HCCs arising in cirrhosis. Data were reviewed from 78 patients with de novo HCCs who were treated with RFA and subsequently transplanted. The last radiological assessment before liver transplantation (LT) was used for comparison between modified Response Evaluation Criteria in Solid Tumors (mRECIST) and histological findings. A total of 125 de novo HCCs (median diameter, 20 mm) were treated with RFA only in 92 sessions. There were 98 nodules that did not show local recurrence during follow‐up (78.4%), and the remaining were retreated, except 1 because of subsequent LT. On explanted livers, complete pathological response (CPR) was observed in 61.6%, being 76.9% when <2 cm, 55.0% when 2‐3 cm, and 30.8% when >3 cm. Tumors near hepatic vessels had CPR in 50% of patients versus 69.3% for tumors distant from vessels (P = 0.039). Of the 125 HCCs, 114 had available radiological assessment within a median of 3 months before LT. Complete radiological response, according to mRECIST, was observed in 77.2% of nodules before LT. The Cohen κ was 0.48 (moderate agreement). The overall accuracy was 78.1%. A total of 18 complications were recorded with only 1 graded as major. In conclusion, RFA can provide high CPR for HCC, especially in smaller tumors distant from hepatic veins or portal branches. The agreement between mRECIST and histology is only moderate. Further refinements in radiological assessment are essential to accurately assess the true effectiveness of RFA.

Percutaneous radiofrequency ablation in intrahepatic cholangiocarcinoma: a retrospective single-center experience

“…However, RFA has recently emerged as a minimally invasive treatment option for hepatic malignancies and as an alternative to resection, especially for patients who have small lesions and/or are unfit for surgical resection [21]. With regard to size, some authors consider RFA a useful technique to provide local control of small, localized, unresectable lesions; in patients with hepatocellular carcinomas (HCCs) 2 cm, for instance, RFA is considered an alternative to hepatic resection because of their comparable long-term efficacy [22,23]. However, the complete ablation rate achieved with RFA declines sharply in the case of larger Univariate and multivariate analysis showed that tumor size less than 20 mm was an independent prognostic factor of LTPFS.…”

Conformal coverage of liver tumors by the thermal coagulation zone in 2450-MHz microwave ablation

“…Thirdly, the characterization models of IS-54 were derived based on ex vivo porcine livers and the proposed correlation might change if there is a large blood vessel in close proximity to the target. Heat sinks caused by large blood vessels during treatment would lead to incomplete thermal coagulation [43,44].…”

Combined Treatments in Liver Ablations

“…A recent study performed in 78 patients with de novo HCCs treated with RFA and subsequently transplanted reported complete pathological response rates of 76.9% in lesions smaller than < 2 cm, 55.0% in lesions 2 to 3 cm, and only 30.8% in lesions above 3 cm. 5 Moreover, high risk of early recurrence after complete ablation has been reported in larger lesions, 6,7 at least partly due to the higher incidence of microsatellite nodules and microvascular invasion. 8,9 Lesion location also plays a major role in treatment success, with perivascular and subcapsular lesions showing lower rates of complete ablation.…”

“…Serra et al reported a complete pathological response rate of 50% in tumors close to the hepatic vessels, compared with 69.3% for tumors distant from the vessels (p ¼ 0.039). 5 Indeed, lesions close to large vessels (< 3 mm) suffer from the so-called "heat sink effect," represented by the heat loss promoted by the adjacent blood flow.…”

“…Incomplete ablation and early tumor recurrence are more frequent in tumors larger than 3 cm and in perivascular or subcapsular locations. 5 Therefore, debate is ongoing on how to improve the results of percutaneous ablation by combining it with other Keywords ► percutaneous ablation ► transarterial chemoembolization ► sorafenib ► ethanol injection ► combined treatments…”