Complications after Radiofrequency Ablation for Hepatocellular Carcinoma: A Multicenter Study Involving 9,411 Japanese Patients

Abstract

Introduction: Radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) is considered a safe and minimally invasive procedure. We previously reported that the mortality and complication rates for RFA were 0.038% (5/13,283 patients) and 3.54% (579 complications/16,346 procedures), respectively, from 1999 to 2010 (previous period). In this study, we investigated the clinical criteria for RFA and the mortality and complication rates from 2011 to 2015 (recent period).

Methods: Data were collected from 25 centers by using a questionnaire developed by the Chugoku-Shikoku Society for Local Ablation Therapy of HCC. The criteria for RFA, RFA modification, use of image-guidance modalities, mortality, and complications during the previous and recent periods were compared.

Results: We evaluated 11,298 procedures for 9,411 patients, including those that involved new devices (bipolar RFA and internally adjustable electrode system). The criterion of hepatic function for RFA increased from a Child-Pugh score ≤8 during the previous period to ≤9 during the recent period. The criteria regarding the tumor location and other risk factors have been expanded recently because of the increased use of several modifications of the RFA procedure and image-guidance modalities. The mortality rate was 0.064% (6/9,411 patients), and the complication rate was 2.92% (330 complications/11,298 procedures). There was no difference in mortality rates between the 2 periods (p = 0.38), but the complication rates was significantly lower during the recent period (p = 0.038).

Discussion and conclusions: Our findings confirmed that RFA, including the use of new devices, is a low-risk procedure for HCC, despite the expansion of the criteria for RFA during the recent period.

Keywords: Complication; Hepatocellular carcinoma; Mortality; Radiofrequency ablation.

Fig. 1

Hepatic function criteria for RFA during the previous (1999–2010, 20 centers) and recent periods (2011–2015, 25 centers). The criteria used during the previous period were as follows: total bilirubin ≤3 mg/dL at 14 (70%) of 20 centers; prothrombin time ≥50% at 11 (55%); platelet count ≥5 × 10⁴/mm³ at 10 (50%); absence of ascites after medication at 15 (50%); and Child-Pugh score ≤8 at 7 (35%). During the recent period, the hepatic function criteria for RFA were as follows: total bilirubin ≤3 mg/dL at 20 (80%) of 25 centers; prothrombin time ≥50% at 13 (52%); platelet count ≥5 × 10⁴/mm³at 19 (76%); absence of ascites after medication at 15 (60%); and Child-Pugh score ≤9 at 12 (48%).

Fig. 2

Criteria regarding tumor location or other factors associated with a higher risk of mortality and complications with RFA of the previous (1999–2010, 20 centers) and the recent (2011–2015, 25 centers) periods. During the previous period, patients with risk I (HCC adjacent to the first or second branch of the portal vein or bile duct) were considered to be RFA candidates at 15 of 20 centers (75%). Those with risk II (HCC adjacent to the origin of the hepatic veins or the inferior vena cava) were candidates at 18 centers (90%). Those with risk III (HCC adjacent to the gallbladder) were candidates at 13 centers (65%). Those with risk IV (a bilioenteric anastomosis or papillary dysfunction) were candidates at 5 centers (25%). During the recent period, patients with risk I, risk II, risk III, and risk IV were considered RFA candidates at 21 of 25 centers (84%), 25 centers (100%), 16 centers (64%), and 10 centers (40%), respectively.

Fig. 3

Several modifications of the RFA procedure during the previous (1999–2010, 20 centers) and recent (2011–2015, 25 centers) periods. During the previous period, procedures included the use of artificial ascites at 17 centers (85%), artificial pleural effusion at 15 (75%), and bile duct cooling using a nasobiliary drainage tube at 5 (25%); during the recent period, these same modifications were performed at 23 (92%), 24 (96%), and 8 centers (32%), respectively.

Fig. 4

Annual trend of the use of RFA during the 5-year period from 2011 to 2015 showing a gradual decline in the number of RFA procedures performed. Of the total number of RFA procedures performed, 87.94% (9,935 procedures) were performed using the Cool-tip Radiofrequency System, 3.67% (415 procedures) were performed using the RTC System, 0.34% (38 procedures) were performed using the RITA RFA System, 4.43% (501 procedures) were performed using the Celon-POWER System, and 3.62% (409 procedures) were performed using the VIVARF System.

Fig. 5

Image-guidance modalities were used for almost half of all RFA procedures (5,294/11,298 procedures; 46.8%). Of 5,294 procedures, 2,397 (45.3%) used CE-US, 2,549 (48.1%) used multimodality fusion imaging, 95 (1.8%) used 3D-SIM, and 253 (4.8%) used CT guidance. CE-US, contrast-enhanced ultrasound; 3D-SIM, 3-dimensional sim-Navigator; CT, computed tomography.

Fig. 6

Annual complication rates for different RFA systems. The complication rates were lowest for the Cool-tip and RTC systems, at approximately 3% each. However, the complication rate was high for the Celon-POWER System during the first 2 years (6.76% in 2013 and 7.30% in 2014), but it decreased sharply in 2015 (2.86%). The complication rates for the VIVARF System and the RITA System were 0.73% and 0% in 2015, respectively.