Perivascular versus nonperivascular small HCC treated with percutaneous RF ablation: retrospective comparison of long-term therapeutic outcomes

A Transformer-Based microvascular invasion classifier enhances prognostic stratification in HCC following radiofrequency ablation

BACKGROUND & AIMS

We aimed to develop a Transformer-based deep learning (DL) network for prognostic stratification in hepatocellular carcinoma (HCC) patients undergoing RFA.

METHODS

A Swin Transformer DL network was trained to establish associations between magnetic resonance imaging (MRI) datasets and the ground truth of microvascular invasion (MVI) based on 696 surgical resection (SR) patients with solitary HCC ≤3 cm, and was validated in an external cohort (n = 180). The multiphase MRI-based DL risk outputs using an optimal threshold of .5 was employed as a MVI classifier for prognosis stratification in the RFA cohort (n = 180).

RESULTS

Over 90% of all enrolled patients exhibited hepatitis B virus infection. Liver cirrhosis was significantly more prevalent in the RFA cohort compared to the SR cohort (72.2% vs. 44.1%, p < .001). The MVI risk outputs exhibited good performance (area under the curve values = .938 and .883) for predicting MVI in the training and validation cohort, respectively. The RFA patients at high risk of MVI classified by the MVI classifier demonstrated significantly lower recurrence-free survival (RFS) and overall survival rates at 1, 3 and 5 years compared to those classified as low risk (p < .001). Multivariate cox regression modelling of a-fetoprotein > 20 ng/mL [hazard ratio (HR) = 1.53; 95% confidence interval (95% CI): 1.02-2.33, p = .047], high risk of MVI (HR = 3.76; 95% CI: 2.40-5.88, p < .001) and unfavourable tumour location (HR = 2.15; 95% CI: 1.40-3.29, p = .001) yielded a c-index of .731 (bootstrapped 95% CI: .667-.778) for evaluating RFS after RFA. Among the three risk factors, MVI was the most powerful predictor for intrahepatic distance recurrence.

CONCLUSIONS

The proposed MVI classifier can serve as a valuable imaging biomarker for prognostic stratification in early-stage HCC patients undergoing RFA.

Thermal ablation for hepatic tumors in high-risk locations

Thermal ablative techniques such as radiofrequency and microwave ablation are minimally invasive and cost-effective approaches that are currently being adopted as alternatives to surgical resection for primary and metastatic liver malignancies. However, they are considered to be relatively contraindicated for tumors in high-risk locations due to technical difficulties and a perceived increased risk of perioperative complications. Several techniques, including artificial ascites, non-touch multibipolar ablation, and laparoscopically assisted ablation, can be used to improve the outcomes of ablation for high-risk tumors. This review aims to provide a comprehensive summary of the techniques currently used to improve thermal ablation outcomes for high-risk liver tumors.

Radiofrequency ablation of subcapsular versus nonsubcapsular hepatocellular carcinomas ≤ 3 cm: analysis of long-term outcomes from two large-volume liver centers

OBJECTIVES

To compare the safety and efficacy of RFA for single HCCs ≤ 3 cm in subcapsular versus nonsubcapsular locations using a propensity score matched analysis.

MATERIALS AND METHODS

This retrospective study included patients with solitary HCCs ≤ 3 cm in size who underwent percutaneous RFA from 2005 to 2015 as initial treatment at two large-volume liver centers. Patients were divided into two groups, consisting of those with subcapsular and nonsubcapsular tumor locations. Complications, local tumor progression (LTP), and overall survival (OS) were compared in these two groups before and after propensity score matching (PSM).

RESULTS

The study population consisted of 964 patients (712 men [74%]) of mean age 58.3 years. Of these 964 patients, 561 (58%) had nonsubcapsular and 403 (42%) had subcapsular HCCs. PSM generated 402 pairs of patients. Major complication rate was low, but significantly higher in the subcapscular group (p = 0.047). Rates of technical effectiveness in these two groups were 99% and 98%, respectively (p = 0.315). However, during follow-up, cumulative 1-, 3-, 5-, and 10-year LTP and OS rates did significantly differ in both entire and PSM cohorts, resulting in the latter 8%, 15%, 20%, and 26% in the nonsubcapsular group vs. 13%, 24%, 30%, and 31% in the subcapsular group (p = 0.015), and 99%, 91%, 80%, and 59% vs. 98%, 85%, 73%, and 50% in the two groups (p = 0.004), respectively.

CONCLUSION

Rates of major complications, LTP, and OS differed significantly following first-line RFA treatment of single HCCs ≤ 3 cm in favor of the nonsubcapsular locations.

CLINICAL RELEVANCE STATEMENT

This large-scale study provides evidence that radiofrequency ablation for small (≤ 3 cm) hepatocellular carcinomas is safer and more effective in nonsubcapsular location than in subcapsular location.

KEY POINTS

• There exist conflicting outcomes on the effectiveness of RFA for early HCC depending on tumor location. • Rate of local tumor progression was significantly higher in the subcapsular hepatocellular carcinomas. • Overall survival rate was significantly poorer in the subcapsular hepatocellular carcinomas.

LI-RADS category is associated with treatment outcomes of small single HCC: surgical resection vs. radiofrequency ablation

OBJECTIVES

To assess whether the Liver Imaging Reporting and Data System (LI-RADS) category is associated with the treatment outcomes of small single hepatocellular carcinoma (HCC) after surgical resection (SR) and radiofrequency ablation (RFA).

METHODS

This retrospective study included 357 patients who underwent SR (n = 209) or RFA (n = 148) for a single HCC of ≤ 3 cm between 2014 and 2016. LI-RADS categories were assigned. Overall survival (OS), recurrence-free survival (RFS), and local tumor progression (LTP) rates after treatment were compared according to the LI-RADS category (LR-4/5 vs. LR-M) before and after propensity score matching (PSM). Prognostic factors for treatment outcomes were assessed.

RESULTS

In total, 357 patients (mean age, 59 years; men, 272) with 357 HCCs (294 LR-4/5 and 63 LR-M) were included. After PSM (n = 78 in each treatment group), there were 10 and 11 LR-M HCCs in the SR and RFA group, respectively. There were no significant differences in OS or RFS. However, SR provided a lower 5-year LTP rate than RFA (1.4% vs. 14.9%, p = 0.001). SR provided a lower 5-year LTP rate than RFA for LR-M HCCs (0% vs. 34.4%, p = 0.062) and LR-4/5 HCCs (1.5% vs. 12.0%, p = 0.008). The LI-RADS category was the sole risk factor associated with poor OS (hazard ratio [HR] 3.79, p = 0.004), RFS (HR 2.12; p = 0.001), and LTP (HR 2.89; p = 0.032).

CONCLUSION

LI-RADS classification is associated with the treatment outcome of HCC, supporting favorable outcomes of SR over RFA for LTP, especially for HCCs categorized as LR-M.

CLINICAL RELEVANCE STATEMENT

Liver Imaging Reporting and Data System category has a potential prognostic role, supporting favorable outcomes of surgical resection over radiofrequency ablation for local tumor progression, especially for hepatocellular carcinoma categorized as LR-M.

KEY POINTS

• SR provided a lower 5-year LTP rate than RFA for HCCs categorized as LR-M (0% vs. 34.4%, p = 0.062) and HCCs categorized as LR-4/5 (1.5% vs. 12.0%, p = 0.008). • There is a steeply increased risk of LTP within 1 year after RFA for LR-M HCCs, compared to SR. • The LI-RADS category was the sole risk factor associated with poor OS (HR 3.79, p = 0.004), RFS (HR 2.12; p = 0.001), and LTP (HR 2.89; p = 0.032) in patients with HCC of ≤ 3 cm treated with SR or RFA.

Drug-Eluting Bead Transarterial Chemoembolization Versus Radiofrequency Ablation as an Initial Treatment of Single Small (≤ 3 cm) Hepatocellular Carcinoma

BACKGROUND

In this study, we aimed to compare the long-term therapeutic outcomes of drug-eluting bead transarterial chemoembolization (DEB-TACE) with those of radiofrequency ablation (RFA) for the initial treatment of a single small (≤ 3 cm) hepatocellular carcinoma (HCC).

METHODS

From January 2010 to December 2021, 259 consecutive patients who underwent DEB-TACE (67 patients) or RFA (192 patients) as a first-line treatment for a single small HCC were enrolled in this retrospective study. The therapeutic outcomes, including cumulative intrahepatic local tumor progression (LTP), progression-free survival (PFS), and long-term overall survival (OS) rates, were compared between the two groups before and after propensity score (PS) matching. Multivariate Cox proportional hazard models were used to evaluate the prognostic factors and differences in OS and PFS between the two groups for all 92 patients after PS matching.

RESULTS

After PS matching, the 1-, 2-, 3-, and 5-year LTP rates were lower in the RFA group than those in the DEB-TACE group (P < 0.001), and the 1-, 2-, 3-, and 5-year PFS rates in the RFA group were higher than those in the DEB-TACE group (P = 0.007). However, the 1-, 2-, 3-, and 5-year OS rates were not significantly different between the RFA and DEB-TACE groups (P = 0.584). Moreover, the OS was not significantly different between the RFA and DEB-TACE groups in the univariate and multivariate analyses, with a hazard ratio (HR) of 0.81. The PFS was significantly higher in the RFA group than that in the DEB-TACE group in the univariate analyses, with a HR of 0.44 (P = 0.009). Multivariate Cox regression analysis showed that albumin (P = 0.019) was an independent prognostic factor for OS. Additionally, the major complication rates were not significantly different between the DEB-TACE and RFA groups (P = 1.000).

CONCLUSION

The LTP and PFS rates of RFA were superior to those of DEB-TACE in the initial treatment of single small HCC after PS matching. However, the OS rates were not significantly different between RFA and DEB-TACE. Therefore, DEB-TACE may be considered an efficient substitute for RFA in some patients with a single small HCC who are ineligible for RFA.

Percutaneous ablation of colorectal liver metastases: a comparison between the outcomes of grayscale US guidance and Sonazoid CEUS Kupffer phase guidance using propensity score matching

PURPOSE

To assess the utility of Sonazoid contrast-enhanced ultrasound (CEUS) for guiding percutaneous microwave ablation (MWA) for colorectal liver metastases (CRLMs).

MATERIALS AND METHODS

The medical records of patients who had undergone ultrasound (US)-guided percutaneous MWA between July 2020 and June 2022, were reviewed. Propensity score matching (PSM) with a ratio of 1:1 was used to balance the potential bias between the grayscale US-guided and Sonazoid CEUS-guided groups. Local tumor progression (LTP), intrahepatic recurrence (IR), and complication rates were compared between the two groups.

RESULTS

Of 252 patients enrolled, 247 achieved complete ablation, and the technical effectiveness was 98.0% (247/252). Of these 247 patients, 158 were in the grayscale US-guided group and 89 in the Sonazoid CEUS-guided group. The median follow-up period was 14.6 months. After PSM, there were no significant differences in LTP, IR, or complication rates between the two groups (p = 0.100, p = 0.511, p > 0.99, respectively). Multivariate analysis identified tumor size ≥ 3 cm (hazard ratio [HR], 7.945; 95% CI, 2.591-24.370; p < 0.001), perivascular (HR, 2.331; 95% CI, 1.068-5.087; p = 0.034), and tumor depth > 8 cm (HR, 3.194; 95% CI, 1.439-7.091; p = 0.004) as significant factors associated with LTP. For tumors with poor vision on grayscale US, Sonazoid CEUS-guided ablation achieved a better LTP rate than grayscale US-guided ablation (3.7% vs.14.8%, p = 0.032).

CONCLUSION

For tumors with poor vision on grayscale US, Sonazoid CEUS guidance is recommended for better local tumor control.

Predictive Factors of Treatment Outcomes After Percutaneous Radiofrequency Ablation of Hepatocellular Carcinoma in the Hepatocaval Confluence: A Propensity Score Matching Analysis

RATIONALE AND OBJECTIVES

To compare the efficacy and complications of ultrasound-guided percutaneous radiofrequency ablation of hepatocellular carcinoma (HCC) in the hepatocaval confluence with those of HCC in the non-hepatocaval confluence and to explore the risk factors that lead to radiofrequency ablation failure and patient local tumor progression (LTP).

MATERIALS AND METHODS

From January 2017 to January 2022, 86 patients with HCC in the hepatocaval confluence who had radiofrequency ablation were included. A 1:1 propensity-matched group of patients with HCC in the non-hepatocaval confluence with comparable clinical baseline traits, such as tumor diameter and tumor number, served as the control group. The two groups' complications, primary efficacy rate (PER), technical success rate (TSR), and prognosis were estimated.

RESULTS

After PSM, no significant difference of TSR (91.7% vs 95.8%, p = 0.491) and PER (95.8% vs 97.2%, p = 1.000) and 1-, 3-, and 5-year LTP rate (12.5% vs 9.9%, 28.2% vs 27.7%, 40.8% vs 43.8%, p = 0.959) and 1-, 3-, and 5-year DFS rate (87.5% vs 87.5%, 62.3% vs 54.2%, 18.1% vs 22.6%, p = 0.437) and 1-, 3-, and 5-year OS rate (94.3% vs 95.7%, 72.7% vs 69.6%, 20.9% vs 33.6%, p = 0.904) was detected between the two groups. The tumor-to-IVC distance was an independent risk factor for radiofrequency ablation failure in HCC patients in the hepatocaval confluence (OR = 0.611, p = 0.022). Besides, tumor diameter was an independent risk factor for predicting LTP in patients with HCC in the hepatocaval confluence (HR = 2.209, p = 0.046).

CONCLUSION

HCC in the hepatocaval confluence can be effectively treated with radiofrequency ablation. To maximize treatment efficacy, the tumor-to-IVC distance and tumor diameter should be assessed before the operation begins.

CT-guided 125I brachytherapy for hepatocellular carcinoma in high-risk locations after transarterial chemoembolization combined with microwave ablation: a propensity score-matched study

BACKGROUND

This study aimed to evaluate the safety and efficacy of ¹²⁵I brachytherapy combined with transarterial chemoembolization (TACE) and microwave ablation (MWA) for unresectable hepatocellular carcinoma (HCC) in high-risk locations.

PATIENTS AND METHODS

After 1:2 propensity score matching (PSM), this retrospectively study analyzed 49 patients who underwent TACE +MWA+¹²⁵I brachytherapy (group A) and 98 patients who only received TACE +MWA (group B). The evaluated outcomes were progression-free survival (PFS), overall survival (OS), and treatment complications. Cox proportional hazards regression analysis survival was used to compare the two groups.

RESULTS

The patients in group A showed a longer PFS than group B (7.9 vs. 3.3 months, P = 0.007). No significant differences were observed in median OS between the two groups (P = 0.928). The objective response rate (ORR), disease control rate of tumors in high-risk locations, and the ORR of intrahepatic tumors were 67.3%, 93.9%, and 51.0%, respectively, in group A, and 38.8%, 79.6% and 29.6%, respectively, in group B (P < 0.001, P = 0.025 and P = 0.011, respectively). TACE-MWA-¹²⁵I (HR = 0.479, P < 0.001) was a significant favorable prognostic factor that affected PFS. The present of portal vein tumor thrombosis was an independent prognostic factor for PFS (HR = 1.625, P = 0.040). The Barcelona clinic liver cancer (BCLC) stage (BCLC C vs. B) was an independent factor affecting OS (HR = 1.941, P = 0.038). The incidence of complications was similar between the two groups, except that the incidence of abdominal pain was reduced in the group A (P = 0.007).

CONCLUSIONS

TACE-MWA-¹²⁵I resulted in longer PFS and better tumor control than did TACE-MWA in patients with unresectable hepatocellular carcinoma in high-risk locations.

Percutaneous ablation of liver metastases from colorectal cancer: a comparison between the outcomes of ultrasound guidance and CT guidance using propensity score matching

PURPOSE

The aim of this study was to compare the effectiveness and outcomes of percutaneous ablation guided by ultrasonography (US) and computed tomography (CT) in colorectal liver oligometastases (CLOM).

METHODS

This study included patients with CLOM treated with percutaneous ablation from January 2008 to January 2021 in this observational study. Only lesions visualized on both CT and US images were further analyzed according to whether patients' initial ablation treatments utilized US guidance or CT guidance. The Kaplan-Meier method was used to estimate local tumor progression (LTP)-free survival after propensity score matching (PSM). The LTP-free survival and treatment-related outcomes were compared between these two groups.

RESULTS

PSM identified 116 patients from each group, with 269 and 238 lesions in the USguided and CT-guided groups, respectively. US-guided ablation had a shorter average procedure time and lower cost than CT-guided ablation (27.54±12.06 minutes vs. 32.70±13.88 minutes, P=0.003; $2,175.13±618.17 vs. $2,455.49±710.25, P=0.002). For patients >60 years of age, the cumulative LTP rate at 1 year was lower in the US-guided group than in the CT-guided group (17.8% vs. 25.1%, P=0.038). For patients with perivascular liver lesions, the cumulative LTP rate at 1 year was lower in the US-guided group (14.4% vs. 28.2%, P=0.040).

CONCLUSION

For patients whose age is >60 years or who have perivascular liver lesions, USguided ablation is better than CT-guided ablation, with a shorter treatment time and lower costs when both ablation methods are feasible for patients.

Usefulness of ultrasound fusion technology for hepatocellular carcinoma localisation, pre- and post-thermal ablation

INTRODUCTION

Percutaneous thermal ablation of inconspicuous lesions can be challenging. Fusion ultrasound (FUS) allows the use of previously performed diagnostic imaging like computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET-CT) to localise hepatocellular carcinoma (HCC) for treatment. This paper illustrates FUS case studies of pre-, intra- and post-ablation imaging of inconspicuous HCC, supplemented by use of contrast-enhanced ultrasound (CEUS).

METHOD

Four prospective cases during September 2014 to October 2018, with HCC amenable to ablation, which were poorly identified on ultrasound, underwent FUS. FUS pre-screening was scheduled within three months of the previous CT or MRI, and between one to four weeks prior to the scheduled ablation date. Post-ablation imaging with FUS was performed between four to six weeks to coincide with their routine follow-up CT or MRI.

FINDINGS

There were potential benefits observed in the cases with combined techniques of FUS and CEUS for limiting circumstances such as heat sink effect, multiple lesions targeting, inconspicuous lesion detection and pre-ablation technical feasibility assessment.

DISCUSSION

The combined use of FUS and CEUS improves tumour visibility, increases operator imaging confidence and reduces heat sink effect during percutaneous thermal ablation.

CONCLUSION

FUS imaging is helpful in targeting poor conspicuity lesions that cannot be detected on grey-scale ultrasound. It facilitates in ensuring optimal treatment of hepatic lesions for improvement of patient prognosis and follow-up imaging.

Stereotactic radiofrequency ablation of tumors at the hepatic venous confluence

BACKGROUND

Radiofrequency ablation (RFA) is subject to "heat-sink" effects, particularly for treatment of tumors adjacent to major vessels.

METHODS

In this retrospective study, 104 patients with 137 tumors (40 HCC, 10 ICC and 54 metastatic liver tumors) close to (≤1 cm from) the hepatic venous confluence underwent stereotactic RFA (SRFA) between June 2003 and June 2018. Median tumor size was 3.7 cm (1.4-8.5) for HCC, 6.4 cm (0.5-11) for ICC and 3.8 cm (0.5-13) for metastases. Endpoints comprised safety, local tumor control, overall and disease-free survival.

RESULTS

The overall major complication rate was 16.0% (20/125 ablations), where 8 (40%) were successfully treated by the interventional radiologist in the same anesthetic session and did not prolong hospital stay. 134/137 (97.8%) tumors were successfully ablated at initial SRFA. Local recurrence (LR) developed in 19/137 tumors (13.9%). The median and overall survival (OS) rates at 1-, 3-, and 5- years from the date of the first SRFA were 51.5 months, 73.5%, 67.0%, and 49.7% for HCC, 14.6 months, 60.0%, 32.0% and 32.0% for ICC and 38.1 months, 91.4%, 56.5% and 27.9% for metastatic disease, respectively.

CONCLUSION

SRFA represents a viable alternative to hepatic resection for challenging tumors at the hepatic venous confluence.

Biliary complications and efficacy after ablation of peribiliary tumors using irreversible electroporation (IRE) or radiofrequency ablation (RFA)

OBJECTIVE

To evaluate the biliary complication rates and efficacy of peribiliary tumor ablation using irreversible electroporation (IRE) or radiofrequency ablation (RFA).

MATERIAL AND METHODS

This is a retrospective study of 42 consecutive patients with 44 peribiliary tumors (≤5 mm distance between the tumor margin and the primary or secondary bile duct). Data were collected between January 2014 and September 2020 from patients who underwent percutaneous liver ablation using IRE (n = 13) or RFA (n = 31).

RESULTS

The median length of follow-up was 23.1 months. The mean tumor size was 17.2 ± 5.2 mm in IRE vs. 18.4 ± 7.0 mm in RFA (p= .56). Complete tumor ablation was achieved in 100% with a significantly larger ablation zone in the IRE group (3.8 ± 0.3 cm vs. 2.6 ± 0.6 cm, p<.001). Significant biliary complications occurred in one patient (7.7%) of the IRE group and in five patients (16.1%) of the RFA group. Significant risk factors for biliary complications included the RFA procedure (HR 9.71, p=.032) and proximity of the tumor to the bile duct (HR 0.63, p=.048). The local tumor progression (LTP) rates were 7.7% (IRE) vs. 21.5% (RFA) at 1 year, 23.1% (IRE) vs. 32.7% (RFA) at 2 years and 23.1% (IRE) vs. 44% (RFA) at 3 years, respectively (p=.289).

CONCLUSIONS

The IRE and RFA procedures are safe and effective to treat peribiliary liver tumors. However, the RFA may have a higher risk of significant bile duct injury than IRE. The shorter distance between the bile duct and the tumor is a strong risk factor for biliary complications.

Cost-Effectiveness Analysis of Follow-Up Schedule for Hepatocellular Carcinoma after Radiofrequency Ablation

Methods

A Markov model was established to evaluate the cost-effectiveness of every 2 months or 2-3 months (2- to 3-month group) versus every 3 months or 3-4 months (3- to 4-month group) posttreatment surveillance in the first two years for HCC after RFA. Transition probabilities and utility values were derived from the literature review. Costs of follow-up were estimated from our institution. The incremental cost-effectiveness ratio (ICER), which was less than $10888 per quality-adjusted life-year (QALY), was considered cost-effective. Sensitivity analyses were performed to determine the uncertainty of the model.

Results

The 2- to 3-month group gained 1.196 QALYs at a cost of $2212.66, while the effectiveness and cost of the 3- to 4-month group were 1.029 QALYs and $1268.92, respectively. The ICER of the 2- to 3-month group versus the 3- to 4-month group was $5651.14 per QALY gained, which was less than the willingness-to-pay threshold of 1-time gross domestic product per capita of China ($10888/QALY). One-way sensitivity analysis showed that the model was most sensitive to the utility of progression-free survival. The probabilistic sensitivity analysis demonstrated that the 2- to 3-month group had a higher probability of being more cost-effective than the 3- to 4-month group when willingness to pay was over $1088.8.

Conclusions

Every 2 months or 2-3 months of follow-up intervals were more cost-effective than 3 months or 3-4 months of follow-up intervals. Thus, the intensive follow-up interval in the first two years was recommended for Child-Pugh class A or B HCC patients within the Milan criteria following RFA.

Suppression of Local Tumor Progression in Perivascular Hepatocellular Carcinoma by Combination Therapy with Radiofrequency Ablation and Percutaneous Ethanol Injection: A Propensity Score Matching Analysis

Background and Aims Radiofrequency ablation (RFA) has replaced percutaneous ethanol injection (PEI) as the treatment of choice for hepatocellular carcinoma (HCC); however, control of local tumor progression (LTP) remains a challenge in perivascular HCC. The aim of this study is to determine whether PEI added to RFA can reduce the LTP rate in perivascular HCC patients. Methods We retrospectively analyzed 167 patients, with 197 newly diagnosed HCC nodules with peritumoral vessels, who underwent either RFA plus PEI or RFA monotherapy as the first-line treatment between June 2001 and April 2015. Ethanol was injected inside the tumor close to the peritumoral vessels in the combination therapy group. Patients were matched 1:1 according to their propensity scores to reduce selection bias; cumulative LTP was then analyzed using log-rank tests and Cox proportional hazard regression analyses. Results The two matched groups comprised 62 tumors each. The overall median follow-up period was 34 months (range, 1-140 months). In the RFA plus PEI group, the cumulative LTP rates were 5.7%, 15.5%, and 20.4% at 1, 3, and 5 years, respectively; in the RFA monotherapy group, the rates were 13.2%, 32.0%, and 40.2%, respectively. The rates were significantly lower in the RFA plus PEI group (P = 0.032). Cox proportional hazard regression analysis showed that PEI combination treatment was significantly associated with a reduced risk of local HCC recurrence (hazard ratio, 0.44; 95% confidence interval, 0.19-0.93; P = 0.031). Discussion/Conclusion The risk of LTP after RFA for perivascular HCC can be significantly reduced by injecting ethanol close to the peritumoral vessels.

Long-term outcome of percutaneous radiofrequency ablation for periportal hepatocellular carcinoma: tumor recurrence or progression, survival and clinical significance

Background/aim

Recent studies have suggested that periportal location of percutaneous radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) is considered as one of the independent risk factors for local tumor progression (LTP). However, the long-term therapeutic outcomes of percutaneous RFA as the first-line therapy for single periportal HCCand corresponding impacts on tumor recurrence or progression are still unclear.

Materials and methods

From February 2011 to October 2020, a total of 233 patients with single nodular HCC ≤ 5 cm who underwent RFA ± transarterial chemoembolization (TACE) as first-line therapy was enrolled and analyzed, including 56 patients in the periportal group and 177 patients in the nonperiportal group. The long-term therapeutic outcomes between the two groups were compared, risk factors of tumor recurrence or progression were evaluated.

Results

The LTP rates at 1, 3, and 5 years were significantly higher in the periportal group than those in the nonperiportal group (15.7, 33.7, and 46.9% vs 6.0, 15.7, and 28.7%, respectively, P = 0.0067). The 1-, 3- and 5-year overall survival (OS) rates in the periportal group were significantly worse than those in the nonperiportal group (81.3, 65.1 and 42.9% vs 99.3, 90.4 and 78.1%, respectively, P<0.0001). In the subgroup of single HCC ≤ 3 cm, patients with periportal HCC showed significantly worse LTP P = 0.0006) and OS (P<0.0001) after RFA than patients with single nonperiportal HCC; The univariate and multivariate analyses revealed that tumor size, periportal HCC and AFP ≥ 400ug/ml were independent prognostic factors for tumor progression after RFA. Furthermore, patients with single periportal HCC had significantly higher risk for IDR(P = 0.0012), PVTT(P<0.0001) and extrahepatic recurrence(P = 0.0010) after RFA than those patients with single nonperiportal HCC. .

Conclusion

The long-term therapeutic outcomes of RFA as the first-line therapy for single periportal HCC were worse than those for single nonperiportal HCC, an increased higher risk of tumor recurrence or progression after RFA was significantly associated with periportal HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-021-00442-2.

Percutaneous radiofrequency ablation near large vessels in beagle livers: the impact of time and distance on the ablation zone

PURPOSE

To investigate the effects of ablation time and distance between the radiofrequency ablation (RFA) electrode tip and a large vessel on the ablation zone in beagle livers.

METHODS

Sixty-one percutaneous RFA coagulation zones were created near large vessels in 10 beagle livers in vivo. The ablated lesions were divided into four groups based on ablation time and distance between the electrode tip and a large vessel (group A, 3 min 0.5 cm; group B, 3 min 0 cm; group C, 5 min 0.5 cm; group D, 5 min 0 cm). The ablated area, long-axis diameters, short-axis diameters, and vessel wall injury were examined.

RESULTS

With a fixed ablation time, the ablation zone created with the electrode tip at 0.5 cm from the large vessel was significantly larger than at 0 cm (p < .05). At a fixed distance between the electrode tip and vessel, the ablation zone created for 5 min was significantly larger than for 3 min (p < .05). The frequency of vessel wall injury in the 0 cm groups was significantly higher than that in the 0.5 cm groups (37.5% vs. 6.9%; p = .003, odds ratio, 7.43). The ratio of width to depth (Dw/Dz) was larger in the 0.5 cm groups than in the 0 cm groups (p < .001).

CONCLUSION

The ablation zone increased with longer ablation times and greater distances between the RFA tip and large vessels for perivascular lesions. The distance between the needle tip and blood vessels is an important factor that affects the overall ablation outcome.

Microwave ablation for peribiliary hepatocellular carcinoma: propensity score analyses of long-term outcomes

OBJECTIVE

To compare the long-term outcomes of MWA as the first-line treatment for HCC in peribiliary versus non-peribiliary locations using propensity score matching analysis.

METHODS

The study participants were recruited between April 2012 and October 2016. In total, 236 patients with HCC <5 cm who underwent ultrasonography-guided percutaneous MWA as the first-line treatment were enrolled. The patients were grouped into two according to tumor location: peribiliary (n = 74) and non-peribiliary (n = 162). The progression-free survival (PFS) and overall survival (OS) rates were compared before and after propensity score matching. Subgroup analyses were conducted for the peribiliary group according to the biliary grading.

RESULTS

Propensity score matching yielded 63 matched pairs of patients. In the two matched groups, cumulative PFS rates were 29.0% and 14.0% in the peribiliary group, and 51.0% and 31.0% in the non-peribiliary group at 3 and 5 years, respectively. Corresponding OS rates were 51.0% and 49.0% in the peribiliary group, and 77.0% and 70.0% in the non-peribiliary group at 3 and 5 years, respectively. In addition, there were significant differences in major complication rates between the two groups (25.7% vs 8.0%; p < .001). In contrast to peribiliary HCCs adjacent to the second-degree branches of intrahepatic bile duct (67.1 ± 5.2 months), subgroup analysis indicated that the mean OS was significantly lower in peribiliary HCCs adjacent to the first-degree branches (51.2 ± 7.5 months) (p = .015).

CONCLUSION

The application of MWA for peribiliary HCC leads to a higher rate of complications and worse long-term tumor control than for non-peribiliary HCC.KEY POINTSThe application of MWA for peribiliary HCC leads to a higher rate of complications than for non-peribiliary HCC.The application of MWA for peribiliary HCC leads to worse long-term tumor control than for non-peribiliary HCC. Abbreviations: Hepatocellular carcinoma (HCC); microwave ablation (MWA); α-fetoprotein (α-FP); local tumor progression (LTP); intrahepatic distal recurrence (IDR); progression-free survival (PFS); overall survival (OS).

Periprocedural risk factors for incomplete radiofrequency ablation of liver metastases from colorectal cancer: a single-center retrospective analysis

OBJECTIVE

To explore independent risk factors for incomplete radiofrequency ablation (iRFA) of colorectal cancer liver metastases (CRLM) and evaluate adverse outcomes following iRFA.

MATERIALS AND METHODS

Magnetic resonance imaging data of CRLM patients who received percutaneous RFA were randomized into training (70%) and validation set 1 (30%) data sets. An independent validation set 2 was derived from computed tomography scans. Uni- and multivariate analyses identified independent risk factors for iRFA. Area under the curve (AUC) values were used to evaluate the predictive model performance. Risk points were assigned to independent predictors, and iRFA was predicted according to the total risk score. Kaplan-Meier curves were used to assess new intrahepatic metastases (NIHM), unablated tumor progression, and overall survival (OS).

RESULTS

Multivariate regression determined as independent iRFA risk factors perivascular tumor location, subcapsular tumor location, tumor size ≥20 mm, and minimal ablative margin ≤5 mm. The AUC values of the model in the training set, validation set 1, and validation set 2 were 0.867, 0.772, and 0.820, respectively. The respective AUC values of the total risk score were 0.864, 0.768, and 0.817. During the 6-year follow-up, the cumulative OS was significantly shorter in the iRFA than in the complete RFA group, and NIHM (hazard ratio [HR] = 2.79; 95% confidence interval [CI]: 1.725, 4.513) and unablated tumor progression (HR = 3.473; 95% CI: 1.506, 8.007) were more severe.

CONCLUSIONS

Perivascular tumor location, subcapsular tumor location, tumor size ≥20 mm, and minimal ablative margin ≤5 mm were independent risk factors for iRFA. iRFA may be a potential predictor of NIHM, unablated tumor progression, and OS.

Radiofrequency ablation versus stereotactic body radiation therapy for small (≤ 3 cm) hepatocellular carcinoma: A retrospective comparison analysis

BACKGROUND AND AIM

We compared the clinical outcomes of radiofrequency ablation (RFA) and stereotactic body radiation therapy (SBRT) in small (≤ 3 cm) hepatocellular carcinoma.

METHODS

A total of 266 patients treated with RFA (n = 179) or SBRT (n = 87) were reviewed. Local control rates (LCRs), intrahepatic recurrence-free survival (IHRFS) rates, and overall survival (OS) rates were compared. Inverse probability of treatment weighting (IPTW) was used to adjust for imbalances in baseline characteristics between the two groups.

RESULTS

The median follow-up period was 50.3 months, and treatment method (RFA vs SBRT) was not a significant prognostic factor for LCR, OS, and IHRFS in both multivariate and IPTW-adjusted analyses. The 4-year LCRs after RFA and SBRT were 92.7% and 95.0%, respectively. Perivascular location was a significant prognostic factor for LCR in the entire patients and in the RFA group, but not in the SBRT group. The 4-year OS rates in the RFA and SBRT groups were 78.1% and 64.1%, respectively (P = 0.012). After IPTW adjustment, the 4-year LCRs (90.6% vs 96.3%) and OS rates (71.8% vs 70.2%) were not significantly different between the two groups. The rate of grade ≥ 3 adverse events was 0.6% (n = 1) in the RFA group and 1.1% (n = 1) in the SBRT group.

CONCLUSIONS

The two treatment methods showed comparable outcomes in terms of LCR, OS rate, and IHRFS rate after IPTW adjustment. SBRT seems to be a viable alternative method for small hepatocellular carcinomas that are not suitable for RFA due to tumor location.

Microwave ablation versus radiofrequency ablation for perivascular hepatocellular carcinoma: a propensity score analysis

BACKGROUND

To compare the efficacy and safety of microwave ablation (MWA) and radiofrequency ablation (RFA) as first-line treatments for perivascular HCC.

METHODS

This multicentre study enrolled 170 patients with perivascular HCC who underwent MWA or RFA. The ablation response, progression-free survival (PFS), overall survival (OS), and complications between the treatment groups for the total and propensity score-matched (PSM) cohorts were compared.

RESULTS

The disease control rates for MWA and RFA were similar in total (94% vs. 91%, p = 0.492) and PSM (93% vs. 93%, p = 1.00) cohorts. The PFS rates at 1, 3, and 5 years were 71%, 55% and 52% in MWA group and 61%, 33% and 28% in RFA group (p = 0.017). The OS rates were comparable between two groups in total (p = 0.249) and PSM cohorts (p = 0.345). In subgroup analyses, the PFS of patients with periportal HCC (45 vs. 36 months, p = 0.048) and a single HCC nodule (51 vs. 42 months, p = 0.014) were significantly better in MWA group than RFA. Major complications were more frequent in the MWA group than in RFA (27% vs. 7%, p < 0.001).

CONCLUSION

Compared with RFA, MWA provides better control of tumour progression especially in periportal HCC or single-nodule perivascular HCC patients.

A novel mono-modality fusion imaging method based on three-dimensional contrast-enhanced ultrasound for the evaluation of ablation margins after microwave ablation of hepatocellular carcinoma

Background

To investigate the feasibility and accuracy of using preoperative and postoperative three-dimensional contrast-enhanced ultrasound (3D CEUS) fusion imaging in the evaluation of safety margins after thermal ablation of hepatocellular carcinoma (HCC).

Methods

A total of the 24 patients with HCC who underwent microwave ablation (MWA) between June 2020 and December 2020 were enrolled in this study. All patients received preoperative and postoperative 3D CEUS. The preoperative and postoperative 3D CEUS images were then fused. The success rate and evaluation time were recorded. The ablation margin and whether or not the safety margin was reached were calculated and recorded. If the ablation safety margin was not reached, the residual ablation volume needed to cover the safety margin was calculated automatically. The agreement between contrast-enhanced computed tomography(CECT) and 3D CEUS fusion imaging in the evaluation of ablation margins was explored using the kappa coefficient.

Results

The 3D CEUS fusion success rate was 95.8% (23/24), with a mean fusion time of (4.1±1.8) minutes. Twenty-three tumors were completely ablated, and the safety margin was achieved for 9 tumors. The ablation margin of 14 tumors was <5 mm. The mean uncovered safety margin volume was (2.27±2.11) mL, and the mean proportion of the uncovered safety margin to the whole safety margin was 16.8%. According to the results of preoperative and postoperative CECT fusion imaging, the ablation margin of 13 tumors was <5 mm, and the ablation margin of 10 tumors was >5 mm. The 2 methods showed excellent consistency, with a Kappa value of 0.911 (P=0.000012).

Conclusions

This study has presented a novel mono-modality fusion imaging method based on CEUS. We demonstrated that 3D CEUS fusion has a short fusion time and a high success rate, as well as good consistency with enhanced CT fusion. Therefore, 3D CEUS fusion is a feasible and accurate tool for evaluating the immediate efficacy of thermal ablation of HCC.

SN, Kulkarni SS, Shetty NS, Gupta A, Gupta S. Indian Society of Vascular and Interventional Radiology Expert Consensus Statements for Ablation in Hepatocellular Carcinoma: Part II

Locoregional therapies play an important role in the management of hepatocellular carcinoma (HCC). Percutaneous ablation is one of the most commonly employed nonsurgical methods for treating very early and early HCC. For small HCC, ablation is potentially curative and competes with surgical resection. The widespread availability and the spectrum of ablative techniques mandate uniform approach among interventional radiologists. Thus, it is desirable to have a consensus regarding various aspects of the liver ablation. This article represents a consensus document of the experts from the Indian Society of Vascular and Interventional Radiology involved in the care of patients with HCC. The statements are presented in two parts.

Changes in gadoxetic-acid-enhanced MR imaging during the first year after irreversible electroporation of malignant hepatic tumors

PURPOSE

To evaluate the appearance and size of ablation zones in gadoxetic-acid-enhanced magnetic resonance imaging (MRI) during the first year after irreversible electroporation (IRE) of primary or secondary hepatic malignancies and to investigate potential correlations to clinical features.

MATERIAL AND METHODS

The MRI-appearance of the ablation area was assessed 1-3 days, 6 weeks, 3 months, 6 months, 9 months and 1 year after IRE. The size of the ablation zone and signal intensities of each follow-up control were compared. Moreover, relationships between clinical features and the MRI-appearance of the ablation area 1-3 days after IRE were analyzed.

RESULTS

The ablation zone size decreased from 5.6 ± 1.4 cm (1-3 days) to 3.7±1.2 cm (1 year). A significant decrease of central hypointensities was observed in T2-blade- (3 months), T2 haste- (6 weeks; 3 months; 6 months; 1 year), T1 arterial phase- (3 months; 1 year), and diffusion-sequences (6 weeks; 3 months; 6 months; 9 months; 1 year). The unenhanced T1-sequences showed significantly increasing central hypointensities (6 weeks; 3 months; 6 months; 9 months; 1 year). Significantly increasing peripheral hypointensities were detected in T1 arterial phase- (3 months; 6 months; 9 months; 1 year) and in T1 portal venous phase-sequences (6 weeks; 3 months; 6 months; 9 months; 1 year). Peripheral hypointensities of unenhanced T1-sequences decreased significantly 1 year after IRE. 1-3 days after IRE central T1 portal venous hypo- or isointensities were detected significantly more often than hyperintensities, if more than 3 IRE electrodes were used.

CONCLUSION

Hepatic IRE results in continuous reduction of ablation zone size during the first postinterventional year. In addition to centrally decreasing T1-signal and almost steadily increasing signal in the enhanced T2 haste-, diffusion- and T1 arterial phase-sequences, there is a trend toward long-term decreasing T1 arterial- and portal venous MRI-signal intensity of the peripheral ablation area, probably representing a region of reversible electroporation.

The effect of tumor location on long-term results of microwave ablation for early-stage hepatocellular carcinoma

BACKGROUND

To analyze the influence of tumor location, including tumor adjacency and located segments on long-term survival outcomes for patients with solitary hepatocellular carcinoma (HCC) after microwave ablation (MWA).

METHODS

This retrospective study evaluated 850 patients. The hepatic segments where the tumor is located, tumor adjacency (important tissues adjacent to tumor) and other clinical characteristics were collected. Overall survival (OS), local tumor progression (LTP) and disease-free survival (DFS) were compared and analyzed. Influence of tumor location was evaluated by multi-models and the effect of adjacency for OS, LTP, and DFS in different segments was analyzed by stratification analysis.

RESULTS

The OS, LTP, and DFS rates were similar in different hepatic segments, so were in high risk and safe locations. In multi-models, HCC in segment 8 showed lower death rate of 43% than that in segment 2 (HR 0.57; P = 0.01) and tumors in segment 6 seemed to have lower LTP rate. Tumors in high-risk locations were risk factors for OS, LTP, and DFS compared with tumors in safe locations, but all differences were not significant in different models. The effects of tumor adjacency on survival outcomes among subgroups of segments were limited.

CONCLUSION

The tumor adjacency was not a prognostic factor of survival outcomes for patients with solitary tumors after MWA, but tumors in segment 8 seemed to better OS rate than tumors in other segments.

Ten-Year Outcomes of Percutaneous Radiofrequency Ablation for Colorectal Cancer Liver Metastases in Perivascular vs. Non-Perivascular Locations: A Propensity-Score Matched Study

Purpose

To compare long-term outcomes of percutaneous radiofrequency ablation for colorectal liver metastases in perivascular versus non-perivascular locations.

Methods

This retrospective study included 388 consecutive patients with colorectal liver metastases (246 men, 142 women; age range 27–86 years) who underwent percutaneous radiofrequency ablation between January 2006 and December 2018. Propensity-score matching was performed for groups with perivascular and non-perivascular colorectal liver metastases. Rates of accumulative local tumor progression, overall survival, intra/extrahepatic recurrence, and complications were compared between the two groups.

Results

We successfully matched 104 patients each in the perivascular and non-perivascular groups (mean age: 60.1 ± 11.5 and 60.1 ± 11.3 years, respectively). Cumulative local tumor progression rates at 6 months, 1 years, 3 years, and 5 years, respectively, were 8.8%,14.8%, 18.9%, and 18.9% in the perivascular group and 8.8%, 13.1%, 15.5%, and 15.5% in the non-perivascular group. The 1-, 3-, 5-, and 10-year overall survival rates, respectively, were 91.3%, 45.6%, 23.9%, and 18.7% in the perivascular group and 88.0%, 47.2%, 27.2%, and 22.6% in the non-perivascular group. No significant between-group differences were detected in cumulative local tumor progression (p=0.567, hazard ratio: 1.224) or overall survival (p = 0.801, hazard ratio: 1.047). The major complication rate was 1.0% (1/104, p > 0.999) in both groups. Tumor size was the only independent prognostic factor for local tumor progression (hazard ratio: 2.314; p = 0.002). On multivariate analysis for overall colorectal liver metastases, tumor diameter >3 cm, tumor location in the right colon, multiple tumors, and extrahepatic metastases before radiofrequency ablation (hazard ratios: 2.046, 1.920, 1.706, and 1.892, respectively; all p < 0.001) and intrahepatic recurrence (hazard ratio: 1.564; p = 0.002) were associated with poor overall survival.

Conclusion

Cumulative local tumor progression, overall survival, and major complications rates did not differ significantly between perivascular and non-perivascular colorectal liver metastases after percutaneous radiofrequency ablation. For perivascular colorectal liver metastases, percutaneous radiofrequency ablation is a safe and effective treatment option.

Factors Associated with Tumor Progression After Percutaneous Ablation of Hepatocellular Carcinoma: Comparison Between Monopolar Radiofrequency and Microwaves. Results of a Propensity Score Matching Analysis

PURPOSE

To identify risk factors for local and distant intrahepatic tumor progression after percutaneous ablation of HCC and to compare MWA with monopolar RFA.

MATERIALS AND METHODS

Consecutive patients with early or very early HCC who underwent percutaneous monopolar RFA or MWA were included. Factors associated with local and distant tumor progression were identified. Propensity score matching (PSM) was used to limit bias. Statistical analyses were performed with the Kaplan-Meier method using the log-rank test and Cox regression models.

RESULTS

One hundred ninety HCC (mean diameter 23 ± 8.6 mm) were treated by RFA (n = 90, 47%) or MWA (n = 100, 53%) in 152 patients (mean age 63 ± 11, 79% men) between 2009 and 2016. The technical success rate was 97.4% (n = 185 HCC). After a median follow-up of 24.6 months (IQR: 9.7-37.2), 43 (23%), HCC showed local tumor progression [after a median of 13.4 months (IQR: 5.8-24.3)] and 91 (63%) patients had distant intrahepatic tumor progression (after a median of 10.4 months (IQR: 5.7-22). The cox model after PSM identified treatment by RFA (HR, 2.89; P = 0.005), HCC size ≥ 30 mm (HR, 3.12; P = 0.007) and vascular contact (HR, 3.43; P = 0.005) as risk factors for local progression. Factors associated with distant intrahepatic progression were HCC ≥ 30 mm (HR, 1.94; P = 0.013), serum AFP > 100 ng/mL (HR, 2.56; p = 0.002), and hepatitis B carrier (HR, 0.51; p = 0.047).

CONCLUSION

The rate of local HCC progression was lower after MWA than monopolar RFA, regardless of tumor size and vascular contact. The ablation technique did not influence the risk of distant intrahepatic tumor progression.

Radiofrequency ablation versus repeat resection for recurrent hepatocellular carcinoma (≤ 5 cm) after initial curative resection

OBJECTIVES

Recurrence rate is up to 70% at 5 years for hepatocellular carcinoma (HCC) after initial resection, but the management of recurrent HCC remains unclear. To compare the efficacy and safety of radiofrequency ablation (RFA) and repeat resection as the first-line treatment in recurrent HCC.

METHODS

This multicenter retrospective study analyzed 290 patients who underwent RFA (n = 199) or repeat resection (n = 91) between January 2006 and December 2016 for locally recurrent HCC (≤ 5 cm) following primary resection. We compared the overall survival (OS), progression-free survival (PFS), and complications between the two treatment groups for the total cohort and the propensity score matched (PSM) cohort.

RESULTS

The 1-, 3-, and 5-year OS (90.7%, 69.04%, 55.6% vs. 87.7%, 62.9%, 38.1%, p = 0.11) and PFS (56.5%, 27.9%, 14.6% vs. 50.2%, 21.9%, 19.2%, p = 0.80) were similar in the RFA group and the repeat resection group. However, RFA was superior to repeat resection in complication rate and hospital stay (p ≤ 0.001). We observed similar findings in the PSM cohort of 48 pairs of patients and when OS and PFS were measured from the time of the primary resection. The OS of the RFA group was significantly better than repeat resection group among those with 2 or 3 recurrent tumor nodules in both the total cohort (p = 0.009) and the PSM cohort (p = 0.018).

CONCLUSION

RFA has the same efficacy as repeat resection in recurrent HCC patients, but with fewer complications. RFA is more efficient and safer than repeat resection in patients with 2 or 3 recurrent tumor nodules.

KEY POINTS

• Recurrence rate is up to 70% at 5 years for hepatocellular carcinoma (HCC) after initial resection. • RFA has the same efficacy as repeat resection in recurrent HCC patients, but with fewer complications. • RFA may be preferred for those with 2 or 3 recurrent HCC nodules.

Percutaneous US-guided MWA of small liver HCC: predictors of outcome and risk factors for complications from a single center experience

The aim of the present study was to identify predictors of outcome and complications in patients with small hepatocellular carcinoma (HCC) treated by percutaneous microwave ablation (MWA). Patients with non-previously treated small (≤ 3 cm) HCCs who underwent ultrasound (US)-guided percutaneous MWA between July 2016 and January 2019 were included. For each patient, the following variables were registered: age, sex, albumin, platelet count, INR/PT, PTT ratio, total bilirubin, liver status, etiology of liver disease, Child-Pugh classification, tumor dimension, margin, and hepatic segment, tumor subcapsular, perihilar or perivascular location, HCC focality, ascites. During follow-up, complications and outcomes were registered. Variables were then analyzed in relation to both outcomes and complications. 74 patients were included. Mean CT follow-up was 6.2 months (range 1-24 months). At least one complication occurred in 48% of patients, the majority being asymptomatic imaging findings not requiring intervention. One major complication was registered (duodenal perforation: 1.3%). The occurrence of complications was associated with HCC multifocality and abnormal INR/PT, duodenal wall edema with tumor dimension, portal vein thrombosis with Child Pugh score, perihepatic free fluid with abnormal platelet count and comorbidities. Incomplete response rate at 1 month was 18.9%. Local tumor progression and new HCC nodules rates were 13.5% and 27%, respectively. Incomplete response at 1 month was associated with both alcoholic etiology of liver disease and II segment tumor location, new HCC nodules with PBC. Despite the small series analyzed, significant factors related with complications and outcomes may be kept in mind when planning the best treatment for each patient.

Iatrogenic Arterioportal Fistula Caused by Radiofrequency Ablation of Hepatocellular Carcinoma: Clinical Course and Treatment Outcomes

PURPOSE

To analyze the clinical course and treatment outcomes of patients with iatrogenic arterioportal fistula (APF) caused by radiofrequency (RF) ablation of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Among the 1,620 hepatocellular carcinoma patients treated by RF ablation between January 2012 and August 2017, 99 who developed APF after RF ablation were included in this retrospective study. Depending on the extent of portal vein enhancement on arterial phase images, APF was classified as massive or nonmassive. The patients' clinical course was investigated and statistically evaluated by univariable and multivariable analyses.

RESULTS

Thrombocytopenia (odds ratio [OR] = 3.939; 95% confidence interval [CI], 1.141-13.598) was the only risk factor for developing massive APF. Eleven patients underwent embolotherapy (technical success rate, 90.9%) and no patients experienced serious adverse events within 30 days of the procedure. Patients with massive APF (66.7%) had a significantly higher chance of a Child-Pugh score increase than did the patients with nonmassive APF (13.6%) (P < .001). Massive APF had a significantly lower chance of natural regression than did nonmassive APF (P < .001). Child-Pugh B (OR = 17.739; 95% confidence interval, 2.361-133.279) and massive APF without treatment (OR = 11.061; 95% confidence interval, 1.257-97.341) were independent risk factors for liver failure that led to death of liver transplant within 1 year after RF ablation.

CONCLUSIONS

Massive APF caused by RF ablation is mostly irreversible and significantly worsens patients' outcomes, but may be effectively treated with embolotherapy.

Radiofrequency Ablation of Hepatocellular Carcinoma (≤ 5 cm) with Saline-Perfused Electrodes: Factors Affecting Local Tumor Progression

Purpose

We aimed to assess local tumor progression (LTP) rate and associated prognostic factors in 92 patients who underwent radiofrequency ablation (RFA) using saline-perfused electrodes to treat hepatocellular carcinoma (HCC) (≤ 5 cm).

Materials and Methods

Total 92 patients with 148 HCCs were treated with RFA using salineperfused electrodes, from 2009 to 2015. We retrospectively evaluated technical success, technique efficacy, and LTP rates. Potential prognostic factors for LTP were perivascular tumor, subphrenic tumor, artificial ascites, tumor size (≥ 2 cm), and previous treatment of transarterial chemoembolization. Analysis was performed by lesion, rather than by person.

Results

During follow-up period from 1 to 97.4 months, total cumulative LTP rates were 7.9%, 11.4%, and 14.6% at 1, 3, and 5 years, respectively. These values were significantly higher in the perivascular (35.1%; p = 0.009) and subphrenic group (38.9%; p = 0.002) at 5-year. We did not observe any significant difference in LTP according to other prognostic factors (p > 0.05).

Conclusion

RFA with saline-perfused electrode is a safe and effective treatment modality for HCC (≤ 5 cm), with lower LTP rates. Nevertheless, perivascular and subphrenic HCCs demonstrated higher LTP rate than other sites. It is imperative to note that perivascular and subphrenic location of HCC are associated with a high risk of local recurrence, despite the use of salineperfused electrodes.

Incidence and evolution of venous thrombosis during the first 3 months after irreversible electroporation of malignant hepatic tumours

The incidence and evolution of venous thrombosis adjacent to the ablation zone after percutaneous irreversible electroporation (IRE) were evaluated to identify potential risk factors in patients with hepatic malignancies. 205 venous structures (in 87 patients) within a ≤1.0 cm radius of the ablation zone were assessed after IRE of 112 hepatic lesions (74 primary, 38 secondary hepatic malignancies) by pre-interventional and post-interventional (1–3 days, 6 weeks and 3 months after IRE) contrast-enhanced magnetic resonance imaging. The relationships between venous thrombosis and clinical features were analysed using a binary logistic regression model. In 27 of 87 patients (31%), a total of 67 venous complications were noted during the 3 months follow-up. Thrombosis represented the most frequently observed complication (n = 47; 70.1%), followed by vessel narrowing (n = 20; 29.9%). 5 (10.6%) of 47 thromboses showed spontaneous regression 3 months after IRE. A small vessel diameter (p = 0.011) and post-interventional vessel narrowing (p = 0.006) were independently associated with delayed post-ablative thrombosis. Delayed venous thrombosis frequently occurs after IRE of hepatic malignancies. Pre-existing vessel narrowing and a small vessel diameter represent significant risk factors that require further surveillance and potentially therapeutic intervention.

RF Ablation Versus Cryoablation for Small Perivascular Hepatocellular Carcinoma: Propensity Score Analyses of Mid-Term Outcomes

PURPOSE

This study aimed to compare radiofrequency (RF) ablation with cryoablation in patients with perivascular hepatocellular carcinoma (HCC) and evaluate the mid-term outcomes of both therapies.

MATERIALS AND METHODS

Between January 2015 and April 2018, 111 patients who underwent percutaneous cryoablation (n = 61) or RF ablation (n = 50) for a single perivascular HCC were included. Perivascular HCC was defined as the presence of contacting peritumoral hepatic vessels that were 3 mm or larger in axial diameter. Local tumor progression (LTP) rates were compared by propensity score matching. Procedure-related complications were also assessed.

RESULTS

The median follow-up was 23 months (range 2-45 months). Twenty-five patients were matched in each group. The cumulative LTP rates at 1 and 3 years were 8.3% and 17.3% in the cryoablation group and 8.7% and 26.1% in the RF ablation group, with no significant difference (p = 0.379). Although there were no significant differences between the two groups, vascular thrombosis (16.0% vs. 9.8%, p = 0.493) and hepatic infarction (12.0% vs. 3.3%, p = 0.137) more frequently occurred in the RF ablation group than in the cryoablation group.

CONCLUSION

In patients with perivascular HCC, cryoablation is an effective alternative treatment compared with RF ablation regarding local tumor control and complications.

LEVEL OF EVIDENCE

Level 4 (retrospective case-control study).

Percutaneous cryoablation for the treatment of liver cancer at special sites: an assessment of efficacy and safety

Background

To assess the safety and efficacy of cryoablation (CA) devices for the treatment of liver cancer at special sites in a retrospective study.

Methods

Special site liver cancer was defined as the tumors directly abutting surrounding structures (such as the liver capsule, gallbladder, vessel, diaphragm, intestine, and adrenal gland) with a maximum distance of 1.0 cm between the tumor and these organs. Sixty-six patients (49 men, 17 women; mean age, 60.8 years; age range, 27-82 years) were included. CA procedure was performed to treat 69 tumors under the guidance of computed tomography or ultrasound. Local tumor progression was assessed during the follow-up. A visual analog scale (VAS) evaluated the pain degree. Complications were assessed during and after every procedure.

Results

The number of tumors under the liver capsule and adjacent to the gallbladder, portal or hepatic vein, diaphragm, intestine, and adrenal gland were 29, 5, 8, 14, 7, and 6, respectively. The median follow-up time was 14 months (range, 2-28 months). In the 69 procedures, the technical success rate was 100%. The cumulative local tumor progression rates at 6, 9, 15, and 24 months were 10.2%, 16.5%, 20.9%, and 30.5%, respectively. No cases of serious complications occurred. During operation, the occurrence rates of subcapsular hemorrhage and pneumothorax were 2.9% and 1.4%, respectively. After the operation, the occurrence rate of biloma, capsular injury, subcapsular planting metastasis, and pneumothorax were 1.4%, 18.8%, 1.4%, and 2.8%, respectively. The average score of 66 patients with a VAS was 2.15±0.63 during the operation.

Conclusions

Percutaneous CA is safe and effective for patients with special site liver cancer.

Stereotactic image-guided microwave ablation of hepatocellular carcinoma using a computer-assisted navigation system

BACKGROUND & AIMS

Ablation plays an important role in the treatment of hepatocellular carcinoma. Because image-guided navigation technology has recently entered the clinical setting, we aimed to analyse its safety, therapeutic and procedural efficiency.

METHODS

Retrospective analysis of patients treated with stereotactic image-guided microwave ablation (SMWA) between January 2015 and December 2017. Interventions were performed using computertomography-guidance with needle trajectory, ablation planning and automatic single-marker patient registration. Needle placement and ablation coverage was controlled by image fusion under general anaesthesia with jet-ventilation.

RESULTS

In total 174 ablations were performed in 88 patients during 119 interventions. Mean age was 66 (46-84) years, 74 (84.1%) were men and 74% were Child Pugh Class A. Median tumour size was 16 (4-45) mm, 62.2% were BCLC A. Median lateral and longitudinal error of needle placement were 3.2 (0.2-14.1) and 1.6 (0-15.8) mm. Median one tumour (1-4) was ablated per session. One patient developed a Dindo IIIb (0.8%) complication, six minor complications. After re-ablation of 12 lesions, an efficacy rate of 96.3% was achieved. Local tumour progression was 6.3% (11/174). Close proximity to major vessels was significantly correlated with local tumour progression (P < .05). Median overall follow-up was 17.5 months after intervention and 24 months after initial diagnosis. BCLC stage, child class and previous treatment were significantly correlated with overall survival (P < .05).

CONCLUSION

Stereotactic image-guided microwave ablation is a safe and efficient treatment for HCC offering a curative treatment approach in general and in particular for lesions not detectable on conventional imaging or untreatable because of difficult anatomic locations.

Percutaneous stereotactic image-guided microwave ablation for malignant liver lesions

Thermal ablation has proven beneficial for hepatocellular carcinoma and possibly for colorectal liver metastases, but data is lacking for other liver metastases. Computer-assisted navigation can increase ablation efficacy and broaden its indications. We present our experience with percutaneous stereotactic image-guided microwave ablation (SMWA) for non-colorectal liver metastases (NCRLM), in form of a retrospective study including all SMWA for NCRLM from 2015 to 2017. Indication for SMWA was determined at a multidisciplinary tumorboard. End-points include recurrence, overall and liver-specific disease progression and complications. Twenty-three patients underwent 25 interventions for 40 lesions, including 17 neuroendocrine tumor, nine breast cancer, four sarcoma, two non-small cell lung cancer, three duodenal adenocarcinoma, one esophageal adenocarcinoma, one pancreatic adenocarcinoma, one ampullary carcinoma, one prostate carcinoma, and one renal cell carcinoma metastases. Median follow-up was 15 months (2-32). Incomplete ablation rate was 2.5% (1/40), local recurrence rate 10% (4/40). Three patients (12%) had minor complications. Overall disease progression was 73.9% (17/23), median disease-free survival 7 months (0-26) and overall survival 18 months (2-39). SIMWA is feasible, safe and minimally invasive for NCRLM in selected patients. While it might offer an alternative to resection or palliative strategies, the oncological benefit needs to be evaluated in a larger patient cohort.

3-D Contrast-Enhanced Ultrasound Fusion Imaging: A New Technique to Evaluate the Ablative Margin of Radiofrequency Ablation for Hepatocellular Carcinoma

To investigate the feasibility of assessing the ablative margin (AM) of radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) with 3-D contrast-enhanced ultrasound fusion imaging (3-DCEUS-FI), pre- and post-RFA 3-DCEUS images of 84 patients with HCC were fused for two radiologists to independently assess the AMs. The success rate, duration and influencing factors for registration; inter-observer agreement for AM classification; and local tumor progression (LTP) rate were evaluated. The success rate of the automatic registration (AR), which was completed within 4-12 s, was 57.1% (48/84). The duration and success rate of the interactive registration (IR) were 4.2 ± 1.8 min and 91.7% (77/84) for radiologist A and 4.8 ± 2.1 min and 91.7% (77/84) for radiologist B, respectively. The multivariate analysis demonstrated that the pre-RFA image quality, number of vessels (≥3 mm) and presence of acoustic shadow were independent factors for AR (p < 0.05), while the number of vessels was an independent factor for IR (p = 0.001). The agreement between observers was excellent (kappa = 0.914). LTP rate was significantly higher for AMs <5 mm than for AMs ≥5 mm (p = 0.024). Quantitatively evaluating the AM immediately after RFA for HCC with 3-DCEUS-FI was feasible.

Combined Therapy with Transarterial Chemoembolization and Radiofrequency Ablation for Hepatocellular Carcinoma: Does the Degree of Ethiodized Oil Accumulation within the Tumor Affect the Therapeutic Efficacy?

PURPOSE

To evaluate the effects of the degree of ethiodized oil accumulation achieved by transarterial chemoembolization followed by radiofrequency (RF) ablation on the treatment efficacy for a single intermediate-sized hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

A total of 153 consecutive patients who underwent chemoembolization and RF ablation for a single intermediate-sized HCC (2-5 cm) were included. On the basis of the degree of ethiodized oil accumulation in HCC on cone-beam CT images, patients who underwent chemoembolization and RF ablation were classified into 2 groups: compact accumulation (≥ 75%) and noncompact accumulation (< 75%). The rates of cumulative local tumor progression (LTP), disease-free survival (DFS), and overall survival (OS) were compared between groups.

RESULTS

Of the 153 patients, 89 were classified into the compact ethiodized oil accumulation group and 64 in the noncompact ethiodized oil accumulation group. There were no significant differences in patient demographic or HCC characteristics between groups except for the incidence of liver cirrhosis (P = .038) and the tumor margin morphology (P = .008). The cumulative LTP rate was significantly lower in the compact accumulation group than in the noncompact accumulation group (P = .013). There were no significant differences in the incidences of complications, DFS rates (P = .055), or OS rates (P = .184).

CONCLUSIONS

The degree of ethiodized oil accumulation does not play a role in decreasing the OS or DFS rate after chemoembolization and RF ablation for intermediate-sized HCC; however, it may contribute to reducing the rate of LTP.

Shrinkage of hepatocellular carcinoma after radiofrequency ablation following transcatheter arterial chemoembolization: Analysis of contributing factors

Objective

This study was conducted to investigate tumor shrinkage and influencing factors in patients with hepatocellular carcinoma (HCC) from radiofrequency (RF) ablation following transcatheter arterial chemoembolization (TACE).

Methods

A total of 222 patients underwent combined sequential treatment of TACE and RF ablation for HCC at our institution between 2008 and 2014. Of those, 86 patients (men, 68; women, 18) who achieved compact iodized oil tagging and complete ablation were included for this retrospective study. We measured three-dimensional tumor diameters and calculated tumor volumes on pre-treatment CT/MRI and follow-up CT scans performed post-TACE, post-ablation, and 1 month post-treatment, respectively. To compare periodically generated tumor diameters and volumes, repeated measures analysis of variance (ANOVA) was applied. Multiple linear regression analysis was performed to identify factors impacting tumor shrinkage after RF ablation.

Results

Diameters and volumes of HCCs declined significantly in the immediate aftermath of RF ablation (i.e., between post-TACE and post-ablation CT scans) (p < 0.001, for both). Mean reduction rates in tumor diameter and volume immediately after RF ablation were 18.2 ± 9.1% and 44.4 ± 14.6%, respectively. Of note, tumors of left hepatic lobe and in subphrenic or perivascular locations showed lower rates of post-ablative volume reduction than those in counterpart locations (p = 0.002, 0.046, 0.024, respectively). Tumor size and liver function did not influence tumor shrinkage after RF ablation.

Conclusion

In patients with HCC, significant tumor shrinkage occurs immediately after RF ablation. The degree of shrinkage in response to ablative treatment seems to vary by tumor location.

Efficacy and Safety of Microwave Ablation (MWA) for Hepatocellular Carcinoma (HCC) in Difficult Anatomical Sites in Egyptian Patients with Liver Cirrhosis

Background and aim: Imaging guided microwave ablation (MWA) for hepatocellular carcinoma (HCC) has become a widely used method over recent years. Tumors close to the diaphragm, gastrointestinal tract, gallbladder, pancreas, hepatic hilum and major bile duct or vessels are generally considered relative contraindications for microwave ablation. This study was conducted to assess the effectiveness and safety of ultrasonography-guided MWA in treating patients with HCC in difficult anatomical sites in comparison to those in conventional sites. Patients and methods: Eighty-eight patients were included and divided into two groups: the study group of 44 with 46 lesions lying <5mm from the diaphragm, hepatic capsule, gall bladder (GB) or large vessel; and the control group of 44 patients with 50 lesions in non-risky sites. Each lesion was ablated using an ultrasound guided microwave probe using a detailed protocol. Results: Most of the patients were males, with a mean age of 57.8 years. In the study group, two patients had lesions adjacent to the GB, twelve were perivascular and 32 were subcapsular. The overall successful ablation rates were 84.8% and 92% in the study and control groups, respectively. Within the study group, ablation rates were 100%, 75% and 87.5% for lesions close to the GB, perivascular lesions and subcapsular lesions, respectively. One patient developed a subcutaneous abscess, with good outcome after proper treatment. Fever, pain and asymptomatic pleural effusion were reported after ablation without statistically significant difference between the groups or among subgroups. In conclusion: MWA for HCC in difficult anatomical sites is as effective and safe as for ordinary sites.

Percutaneous ablation for perivascular hepatocellular carcinoma: Refining the current status based on emerging evidence and future perspectives

Various therapeutic modalities including radiofrequency ablation, cryoablation, microwave ablation, and irreversible electroporation have attracted attention as energy sources for effective locoregional treatment of hepatocellular carcinoma (HCC); these are accepted non-surgical treatments that provide excellent local tumor control and favorable survival. However, in contrast to surgery, tumor location is a crucial factor in the outcomes of locoregional treatment because such treatment is mainly performed using a percutaneous approach for minimal invasiveness; accordingly, it has a limited range of ablation volume. When the index tumor is near large blood vessels, the blood flow drags thermal energy away from the targeted tissue, resulting in reduced ablation volume through a so-called “heat-sink effect”. This modifies the size and shape of the ablation zone considerably. In addition, serious complications including infarction or aggressive tumor recurrence can be observed during follow-up after ablation for perivascular tumors by mechanical or thermal damage. Therefore, perivascular locations of HCC adjacent to large intrahepatic vessels can affect post-treatment outcomes. In this review, we primarily focus on physical properties of perivascular tumor location, characteristics of perivascular HCC, potential complications, and clinical outcomes after various locoregional treatments; moreover, we discuss the current status and future perspectives regarding percutaneous ablation for perivascular HCC.

Tumor Location Influences Oncologic Outcomes of Hepatocellular Carcinoma Patients Undergoing Radiofrequency Ablation

Radiofrequency ablation (RFA) is recommended as a first-line therapy for small hepatocellular carcinoma (HCC). Tumor location is a potential factor influencing the procedure of RFA. To compare oncologic outcomes of RFA for different tumor locations, this retrospective study enrolled 194 patients with small HCC who had undertaken RFA. The HCC nodules were classified as peri-hepatic-vein (pHV) or non-pHV, peri-portal-vein (pPV) or non-pPV, and subcapsular or non-subcapsular HCC. The regional recurrence-free survival (rRFS), overall survival (OS), recurrence-free survival (recurrence in any location, RFS) and distant recurrence-free survival (dRFS) were compared. Operation failures were recorded in five pPV HCC patients, which was more frequent than in non-pPV HCC patients (p = 0.041). The 1-, 3-, and 5-year rRFS was 68.7%, 53.7%, and 53.7% for pHV patients and 85.1%, 76.1%, and 71.9% for non-pHV patients, respectively (p = 0.012). After propensity score matching, the 1-, 3-, and 5-year rRFS was still worse than that of non-pHV patients (p = 0.013). The OS, RFS, and dRFS were not significantly different between groups.

CONCLUSIONS

A pHV location was a risk factor for the regional recurrence after RFA in small HCC patients. The tumor location may not influence OS, RFS, and dRFS. Additionally, a pPV location was a potential high-risk factor for incomplete ablation.

Percutaneous cryoablation for perivascular hepatocellular carcinoma: Therapeutic efficacy and vascular complications

OBJECTIVES

To evaluate the therapeutic efficacy of and vascular complications associated with percutaneous cryoablation for the treatment of perivascular HCC.

METHODS

Between August 2015 and September 2017, 58 consecutive patients (48 men, 10 women; mean age, 61.1 years; age range, 44-84 years) who underwent percutaneous cryoablation were included. All patients had a single perivascular HCC (mean size, 1.3 cm; Barcelona clinic liver cancer-stage 0 or A) that was in contact with hepatic vessels, ≥ 3 mm or larger in axial diameter. Local tumour progression (LTP) was estimated by the Kaplan-Meier method. In addition, several procedure-related vascular complications were evaluated immediately after treatment and during follow-up CT: peritumoral vessel thrombosis; infarction; aggressive intrasegmental recurrence (AIR) (the simultaneous development of ≥ 3 nodular or infiltrative tumours). The follow-up CT was performed in all patients 1 month after the procedure, and every 3 months thereafter.

RESULTS

The median follow-up period was 22 months (range, 3-29 months). The technical success rate of cryoablation was 96.6% (56/58). The 1- and 2-year cumulative LTP rates were 3.6% and 14.6%, respectively. Although peritumoral vessel thrombosis occurred in 6.9% of cases (4/58), no cases of hepatic infarction were observed and AIR did not develop during follow-up. Half of the thombi in the peritumoral vessels immediately after cryoablation disappeared on follow-up CT images.

CONCLUSION

Cryoablation could be an effective tool for the treatment of perivascular HCC with a very low risk of vascular complications.

KEY POINTS

• Cryoablation allowed a high technical success rate for perivascular HCC. • Only 6.9% developed peritumoral vessel thrombosis without major vascular complications like infarction. • Two-year cumulative LTP rate was 14.6%, without aggressive tumour recurrence on follow-up.

Radiofrequency ablation vs. surgery for perivascular hepatocellular carcinoma: Propensity score analyses of long-term outcomes

BACKGROUND & AIMS

The therapeutic outcomes of surgical resection (SR) or radiofrequency ablation (RFA) for perivascular hepatocellular carcinoma (HCC) have not been compared. The aim of this study was to compare SR with RFA as first-line treatment in patients with perivascular HCC and to evaluate the long-term outcomes of both therapies.

METHODS

This retrospective study was approved by the institutional review board. The requirement for informed consent was waived. Between January 2006 and December 2010, a total of 283 consecutive patients with small perivascular HCCs (≤3 cm, Barcelona Clinic Liver Cancer stage 0 or A) underwent SR (n = 182) or RFA (n = 101) as a first-line treatment. The progression-free survival (PFS) and overall survival (OS) rates were compared by propensity score matching. Subgroup analysis of these outcomes was conducted according to the type of hepatic vessels.

RESULTS

The median follow-up was 7.8 years. Matching yielded 62 pairs of patients. In the two matched groups, the PFS rates at 5 and 10 years were 58.0% and 17.8%, respectively, in the SR group, and 25.4% and 14.1%, respectively, in the RFA group (p <0.001). The corresponding OS rates at 5 and 10 years were 93.5% and 91.9% in the SR group and 82.3% and 74.1% in the RFA group, respectively (p <0.001). In contrast to those in patients with perivenous HCCs, subgroup analysis indicated that extrahepatic recurrence and OS were significantly different according to the treatment modality in patients with periportal HCCs (p = 0.004 and p <0.001, respectively).

CONCLUSIONS

In patients with small perivascular HCCs, SR provided better long-term tumor control and OS than RFA, particularly for periportal tumors.

LAY SUMMARY

Surgical resection and radiofrequency ablation are both treatment options for perivascular hepatocellular carcinoma. We compared outcomes in patients treated with either method. Surgical resection provided better long-term tumor control and overall survival than radiofrequency ablation for patients with a small perivascular hepatocellular carcinoma (≤3 cm) as a first-line treatment, particularly for periportal tumors. The location of the tumor and the type of peritumoral hepatic vessels need to be considered when choosing between surgical resection and radiofrequency ablation for small HCCs.

Hepatocellular carcinoma abutting large vessels: comparison of four percutaneous ablation systems

PURPOSE

To compare overall local tumour progression (OLTP), defined as the failure of primary ablation or local tumour progression, with single applicator monopolar radiofrequency ablation (RFA), microwave ablation (MWA), cluster-RFA and multi-bipolar radiofrequency (mbpRFA) in the treatment of hepatocellular carcinoma (HCC) ≤ 5 cm abutting large vessels (≥3 mm).

MATERIALS AND METHODS

This multicenter, retrospective, per-nodule study was performed from 2007 to 2015. The study was approved by the ethics review board, and informed consent was waived. A total of 160/914 HCC nodules treated by thermal ablation and abutting large vessels (40 per treatment group) treated by monopolar RFA, MWA, cluster-RFA or mbpRFA were matched for tumour size, alpha-feto-protein level and vessel size. OLTP rates were compared by the log-rank test and the multivariate Cox model after matching.

RESULTS

No differences were observed in tumour size, vessel size or alpha-feto-protein levels among the three groups (p = 1). The cumulative 4-year OLTP rates following monopolar RFA, cluster-RFA, multi-bipolar RFA and MWA were 50.5%, 16.3%, 16.3% and 44.2%, respectively (p = 0.036). On multivariate Cox regression, vessel size ≥10 mm, monopolar RFA and MWA were independent risk factors of OLTP compared to cluster-RFA or mbpRFA.

CONCLUSION

Multi-applicator RFA provides better local tumour control in HCC abutting large vessels than single-applicator techniques (monopolar RFA or MWA).

Percutaneous treatment of hepatocellular carcinoma: State of the art and innovations

Percutaneous treatment of hepatocellular carcinoma (HCC) encompasses a vast range of techniques, including monopolar radiofrequency ablation (RFA), multibipolar RFA, microwave ablation, cryoablation and irreversible electroporation. RFA is considered one of the main curative treatments for HCC of less than 5 cm developing on cirrhotic liver, together with surgical resection and liver transplantation. However, controversies exist concerning the respective roles of ablation and liver resection for HCC of less than 3 to 5 cm on cirrhotic liver. In line with the therapeutic algorithm of early HCC, percutaneous ablation could also be used as a bridge to liver transplantation or in a sequence of upfront percutaneous treatment, followed by transplantation if the patient relapses. Moreover, several innovations in ablation methods may help to efficiently treat early HCC, initially considered as "non-ablatable", and might, in some cases, extend ablation criteria beyond early HCC, enabling treatment of more patients with a curative approach.

Outcomes of microwave ablation for hepatocellular carcinoma adjacent to large vessels: a propensity score analysis

The aim of this study was to retrospectively compare the long-term efficacy of MW ablation as a curative therapy for hepatocellular carcinoma(HCC) adjacent to large vessels(≥3 mm) with that in safe location. Between 2010 and 2016, 406 patients diagnosed with early-stage HCC at Chinese PLA general hospital were enrolled. One-to-one matched pairs between the vessel group and the safe group were generated using propensity score matching. The associations of treatment strategy with overall survival and local tumor progression were determined by Cox regression. Before matching, 113 patients were classified into the vessel group and 293 patients were classified into the vessel group. The patients in the vessel group were more frequently classified as larger tumor size (P<0.05) and higher AFP level (P<0.05) than patients in the safe group. After propensity score matching, 113 pairs of well-matched HCC patients were selected from different treatment groups. No significant differences were found in local tumor progression, overall survival and complication rates for MW ablation as a first-line treatment for the early-stage HCC between two groups. In conclusion, MW ablation provides an effective and safe way to treat early-stage HCC adjacent to large vessels.

Effect of oral antiviral treatment on long-term outcomes of radiofrequency ablation therapy for hepatitis B virus-related hepatocellular carcinoma

OBJECTIVES

This study aimed to investigate the effect of oral antiviral treatment on the prognosis of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) after radiofrequency (RF) ablation.

METHODS

Between January 2003 and December 2010, 228 patients without a history of antiviral treatment were treated with RF ablation for a single HBV-related HCC. We divided the patients into two groups, patients who received (n=125) or did not receive antiviral treatment (n=103), based on whether oral antiviral treatment was administered after RF ablation. The median duration of antiviral treatment was 60.1 months. HCC recurrence and overall survival were compared in the two groups in the full cohort and the propensity score-matched cohort.

RESULTS

In the matched cohort, the probability of HCC recurrence at 5 years was 43.8% for the non-antiviral treatment group and 14.7% for the antiviral treatment group (p<0.001). The probability of overall survival at 5 years was 77.2% for the non-antiviral treatment group and 93.5% for the antiviral treatment group (p=0.002). Multivariable analysis showed that risk factors for HCC recurrence included large tumor size (hazard ratio (HR)=1.30, p=0.022), HBV DNA serum level (HR=1.11, p=0.005), and serum AFP level ≥20 ng/mL (HR=1.66, p=0.005). Overall survival was associated with larger tumor size (HR=1.86, p=0.001) and Child-Pugh Class B (HR=2.13, p=0.019). Oral antiviral treatment after RF ablation was significantly associated with a lower risk of tumor recurrence and death (HR=0.33, p<0.001, and HR=0.44, p=0.004).

CONCLUSION

Use of oral antiviral treatment after curative RF ablation was associated with favorable outcomes in terms of tumor recurrence and overall survival in patients with HBV-related HCC.