Percutaneous thermal ablation for the treatment of colorectal liver metastases and hepatocellular carcinoma: a comparison of local therapeutic efficacy

The Relationship Between Rim-like Enhancement on Pre-ablation Contrast-enhanced Ultrasound of Colorectal Liver Metastasis and Early Intrahepatic Progression After Thermal Ablation: A Preliminary Study

OBJECTIVE

To investigate the relationship between the rim-like enhancement pattern on pre-ablation contrast-enhanced ultrasound (CEUS) of colorectal liver metastasis (CRLM) and the therapeutic efficacy of percutaneous microwave ablation (MWA).

METHODS

Patients with CRLM underwent MWA and were evaluated using CEUS before ablation in our hospital between February 2020 and February 2023 were enrolled in this retrospective study. The enhancement patterns of CRLM were assessed by two radiologists and classified as rim-like enhancement and non-rim-like enhancement patterns. The therapeutic outcomes, including cumulative intrahepatic progression rate and early intrahepatic progression rate, were followed up and analyzed.

RESULTS

Overall, 50 patients with 121 nodules were enrolled. Rim-like enhancement pattern was observed in 18 patients (18/50, 36.0%). The cumulative intrahepatic progression rate was significantly higher in the rim-like enhancement group than the rate in the non-rim-like enhancement group (p = 0.022). The early intrahepatic progression rate in the rim-like enhancement group was also significantly higher than the rate in the non-rim-like enhancement group (12/17, 70.6% vs. 6/24, 25.0%, p = 0.005). The multivariable analysis demonstrated that the rim-like enhancement pattern of CRLM was a significant risk factor associated with early intrahepatic progression after MWA (p = 0.013).

CONCLUSION

Rim-like enhancement pattern on pre-ablation CEUS of CRLM was associated with a higher risk of intrahepatic progression after MWA.

Prediction of Local Tumor Progression After Thermal Ablation of Colorectal Cancer Liver Metastases Based on Magnetic Resonance Imaging Δ-Radiomics

PURPOSE

This study aimed to enhance the predictability of local tumor progression (LTP) postthermal ablation in patients with colorectal cancer liver metastases (CRLMs). A sophisticated approach integrating magnetic resonance imaging (MRI) Δ-radiomics and clinical feature-based modeling was employed.

MATERIALS AND METHODS

In this retrospective study, 37 patients with CRLM were included, encompassing a total of 57 tumors. Radiomics features were derived by delineating the images of lesions pretreatment and images of the ablation zones posttreatment. The change in these features, termed Δ-radiomics, was calculated by subtracting preprocedure values from postprocedure values. Three models were developed using the least absolute shrinkage and selection operators (LASSO) and logistic regression: the preoperative lesion model, the postoperative ablation area model, and the Δ model. Additionally, a composite model incorporating identified clinical features predictive of early treatment success was created to assess its prognostic utility for LTP.

RESULTS

LTP was observed in 20 out of the 57 lesions (35%). The clinical model identified, tumor size (P = 0.010), and ΔCEA (P = 0.044) as factors significantly associated with increased LTP risk postsurgery. Among the three models, the Δ model demonstrated the highest AUC value (T2WI AUC in training, 0.856; Delay AUC, 0.909; T2WI AUC in testing, 0.812; Delay AUC, 0.875), whereas the combined model yielded optimal performance (T2WI AUC in training, 0.911; Delay AUC, 0.954; T2WI AUC in testing, 0.847; Delay AUC, 0.917). Despite its superior AUC values, no significant difference was noted when comparing the performance of the combined model across the two sequences (P = 0.6087).

CONCLUSIONS

Combined models incorporating clinical data and Δ-radiomics features serve as valuable indicators for predicting LTP following thermal ablation in patients with CRLM.

Sex-Differences in Post-Procedural Pain Experiences After Thermal Liver Ablations for Liver Tumors: A Retrospective Study

INTRODUCTION

Literature shows differences in pain experiences between sexes. The exact influence of thermal liver ablation on experienced pain is still not well-known. This study aims to investigate the maximum pain intensity at the recovery between men and women after percutaneous thermal liver ablation.

METHODS

Patients treated with percutaneous thermal liver ablation (radiofrequency or microwave ablation) in Maastricht University Medical Center + between 2018 and 2022 for primary or secondary liver tumors were included retrospectively. Outcomes included maximum numerical rating scale (NRS, scale:0-10) score at the recovery room, prevalence of post-procedural pain (defined as NRS score ≥ 4), duration of anesthesia, length of stay at recovery, and complications. Regression analyses were adjusted for age, ASA-score, BMI, tumor type, maximum diameter of lesion, chronic pain in patients' history, and history of psychological disorder.

RESULTS

183 patients were included of which 123 men (67%). Results showed higher average maximum NRS scores in women patients compared to men (mean:3.88 versus 2.73), but not after adjustments (aß:0.75, 95%CI:-0.13-1.64). Women suffered more from acute post-procedural pain (59% versus 35%; aOR:2.50, 95%CI:1.16-5.39), and needed analgesics more often at the recovery room (aOR:2.43, 95%CI:1.07-5.48) compared to men. NRS score at recovery arrival did not significantly differ (aß:0.37, 95%CI:-0.48-1.22). No differences were seen in the length of stay at the recovery, duration of anesthesia, procedure time, and complication rate. Location of the tumor (subcapsular or deep), total tumors per patient, and distinction between primary and secondary tumors had no influence on the NRS.

CONCLUSION

This retrospective single-center study shows higher post-procedural pain rates after thermal liver ablation in women, resulting in higher analgesics use at the recovery room. The results suggest considering higher dosage of analgesics during thermal liver ablation in women to reduce post-procedural pain. LEVEL OF EVIDENCE 3: Non-controlled retrospective cohort study.

Independent validation of CT radiomics models in colorectal liver metastases: predicting local tumour progression after ablation

OBJECTIVES

Independent internal and external validation of three previously published CT-based radiomics models to predict local tumor progression (LTP) after thermal ablation of colorectal liver metastases (CRLM).

MATERIALS AND METHODS

Patients with CRLM treated with thermal ablation were collected from two institutions to collect a new independent internal and external validation cohort. Ablation zones (AZ) were delineated on portal venous phase CT 2-8 weeks post-ablation. Radiomics features were extracted from the AZ and a 10 mm peri-ablational rim (PAR) of liver parenchyma around the AZ. Three previously published prediction models (clinical, radiomics, combined) were tested without retraining. LTP was defined as new tumor foci appearing next to the AZ up to 24 months post-ablation.

RESULTS

The internal cohort included 39 patients with 68 CRLM and the external cohort 52 patients with 78 CRLM. 34/146 CRLM developed LTP after a median follow-up of 24 months (range 5-139). The median time to LTP was 8 months (range 2-22). The combined clinical-radiomics model yielded a c-statistic of 0.47 (95%CI 0.30-0.64) in the internal cohort and 0.50 (95%CI 0.38-0.62) in the external cohort, compared to 0.78 (95%CI 0.65-0.87) in the previously published original cohort. The radiomics model yielded c-statistics of 0.46 (95%CI 0.29-0.63) and 0.39 (95%CI 0.28-0.52), and the clinical model 0.51 (95%CI 0.34-0.68) and 0.51 (95%CI 0.39-0.63) in the internal and external cohort, respectively.

CONCLUSION

The previously published results for prediction of LTP after thermal ablation of CRLM using clinical and radiomics models were not reproducible in independent internal and external validation.

CLINICAL RELEVANCE STATEMENT

Local tumour progression after thermal ablation of CRLM cannot yet be predicted with the use of CT radiomics of the ablation zone and peri-ablational rim. These results underline the importance of validation of radiomics results to test for reproducibility in independent cohorts.

KEY POINTS

• Previous research suggests CT radiomics models have the potential to predict local tumour progression after thermal ablation in colorectal liver metastases, but independent validation is lacking. • In internal and external validation, the previously published models were not able to predict local tumour progression after ablation. • Radiomics prediction models should be investigated in independent validation cohorts to check for reproducibility.

Repeat hepatectomy versus thermal ablation therapy for recurrent hepatocellular carcinoma: a systematic review and meta-analysis

Background

This meta-analysis was conducted to assess the survival benefits of repeat hepatectomy (RH) and thermal ablation therapy (TAT) in managing recurrent hepatocellular carcinoma (HCC).

Methods

A comprehensive search was conducted in the PubMed, SinoMed, Embase, Cochrane Library, Medline, and Web of Science databases using relevant keywords to identify all studies published on this specific topic. Pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were estimated using a fixed-effects model.

Results

This meta-analysis included a total of 21 studies, comprising 2580 patients with recurrent HCC, among whom 1189 underwent RH and 1394 underwent TAT. Meta-analysis results demonstrated that the RH group exhibited superior overall survival (OS) (HR=0.85, 95%CI 0.76∼0.95, P=0.004) and recurrence-free survival (RFS) (HR=0.79, 95%CI 0.7∼0.9, P<0.01) compared to the TAT group. Regarding postoperative complications, the TAT group experienced fewer complications than the RH group (OR=3.23, 95%CI 1.48∼7.07, P=0.003), while no significant difference in perioperative mortality was observed between the two groups (OR=2.11, 95%CI 0.54∼8.19, P=0.28).

Conclusion

The present study demonstrates that, in comparison to TAT, RH may confer superior survival benefits for patients with recurrent HCC.

3D fusion is superior to 2D point-to-point contrast-enhanced US to evaluate the ablative margin after RFA for hepatocellular carcinoma

PURPOSE

To compare the efficiency of three-dimensional (3D) and two-dimensional (2D) contrast-enhanced ultrasound (CEUS)-derived techniques in evaluating the ablative margin (AM) after radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC).

METHODS

In total, 98 patients with 98 HCCs were enrolled. The 2D CEUS point-to-point imaging (2D CEUS-PI) was conducted by comparing the pre- and post-RFA 2D CEUS images manually, and the 3D CEUS fusion imaging (3D CEUS-FI) was conducted by fusing the pre- and post-RFA 3D CEUS images automatically. These two techniques were compared in distinguishing an adequate AM ≥ 5 mm. Risk factors for local tumor progression (LTP) after RFA were analyzed by the Kaplan-Meier method with log-rank test.

RESULTS

The mean registration time of 3D CEUS-FI and 2D CEUS-PI was 5.0 and 9.3 min, respectively (p < 0.0001). The kappa coefficient was 0.680 for agreement between 2D CEUS-PI and 3D CEUS-FI in the evaluation of AM (p < 0.0001). Tumors with AM < 5 mm by 2D CEUS-PI were all identified as AM < 5 mm by 3D CEUS-FI. Nonetheless, 16 (26%) tumors identified as AM ≥ 5 mm by 2D CEUS-PI were re-classified as AM < 5 mm by 3D CEUS-FI. During a median follow-up time of 31.2 months (range, 3.2-66.0 months), LTP was identified in 8 tumors. The estimated 1-/2-/3-year cumulative incidence of LTP was 4.4%, 8.1%, and 10.3%, respectively. Higher estimated cumulative incidence of LTP was identified in tumors with AM < 5 mm by 2D CEUS-PI (at 3-year, 27.2% vs 0%; p < 0.001), and by 3D CEUS-FI (at 3-year, 20.7% vs 0%; p = 0.004).

CONCLUSION

3D CEUS-FI excelled in the evaluation of AM when compared with 2D CEUS-PI. With equivalent efficacy in the prediction of LTP, 3D CEUS-FI was superior to 2D CEUS-PI for its automatic and time-saving procedure.

CLINICAL RELEVANCE STATEMENT

3D CEUS fusion imaging may serve as an effective tool in evaluating ablative margin and predicting local tumor progression after RFA in HCC.

KEY POINTS

• Both 2D and 3D CEUS-derived techniques could evaluate ablative margin (AM) after RFA for hepatocellular carcinoma. • 3D CEUS fusion imaging was more precise in the evaluation of AM compared to 2D CEUS point-to-point imaging, with advantages of its automatic and time-saving procedure. • An inadequate AM < 5 mm evaluated by CEUS-derived techniques was the only risk factor of LTP after RFA for hepatocellular carcinoma (p < 0.001 for 2D CEUS point-to-point imaging, and p = 0.004 for 3D CEUS fusion imaging).

The Importance of Optimal Thermal Ablation Margins in Colorectal Liver Metastases: A Systematic Review and Meta-Analysis of 21 Studies

BACKGROUND

Colorectal cancer (CRC) is the second most common cause of cancer-related deaths in the US. Thermal ablation (TA) can be a comparable alternative to partial hepatectomy for selected cases when eradication of all visible tumor with an ablative margin of greater than 5 mm is achieved. This systematic review and meta-analysis aimed to encapsulate the current clinical evidence concerning the optimal TA margin for local cure in patients with colorectal liver metastases (CLM).

METHODS

MEDLINE, EMBASE, and the CENTRAL databases were systematically searched from inception until 1 May 2023, in accordance with the PRISMA Guidelines. Measure of effect included the risk ratio (RR) with 95% confidence interval (CI) using the random-effects model.

RESULTS

Overall, 21 studies were included, comprising 2005 participants and 2873 ablated CLMs. TA with margins less than 5 mm were associated with a 3.6 times higher risk for LTP (n = 21 studies, RR: 3.60; 95% CI: 2.58-5.03; p-value < 0.001). When margins less than 5 mm were additionally confirmed by using 3D software, a 5.1 times higher risk for LTP (n = 4 studies, RR: 5.10; 95% CI: 1.45-17.90; p-value < 0.001) was recorded. Moreover, a thermal ablation margin of less than 10 mm but over 5 mm remained significantly associated with 3.64 times higher risk for LTP vs. minimal margin larger than 10 mm (n = 7 studies, RR: 3.64; 95% CI: 1.31-10.10; p-value < 0.001).

CONCLUSIONS

This meta-analysis solidifies that a minimal ablation margin over 5 mm is the minimum critical endpoint required, whereas a minimal margin of at least 10 mm yields optimal local tumor control after TA of CLMs.

Quantitative dual-energy computed tomography with cesium as a novel contrast agent for localization of thermochemical ablation in phantoms and ex vivo models

BACKGROUND

Thermochemical ablation (TCA) is a minimally invasive therapy under development for hepatocellular carcinoma. TCA simultaneously delivers an acid (acetic acid, AcOH) and base (sodium hydroxide, NaOH) directly into the tumor, where the acid/base chemical reaction produces an exotherm that induces local ablation. However, AcOH and NaOH are not radiopaque, making monitoring TCA delivery difficult.

PURPOSE

We address the issue of image guidance for TCA by utilizing cesium hydroxide (CsOH) as a novel theranostic component of TCA that is detectable and quantifiable with dual-energy CT (DECT).

MATERIALS AND METHODS

To quantify the minimum concentration of CsOH that can be positively identified by DECT, the limit of detection (LOD) was established in an elliptical phantom (Multi-Energy CT Quality Assurance Phantom, Kyoto Kagaku, Kyoto, Japan) with two DECT technologies: a dual-source system (SOMATOM Force, Siemens Healthineers, Forchheim, Germany) and a split-filter, single-source system (SOMATOM Edge, Siemens Healthineers). The dual-energy ratio (DER) and LOD of CsOH were determined for each system. Cesium concentration quantification accuracy was evaluated in a gelatin phantom before quantitative mapping was performed in ex vivo models.

RESULTS

On the dual-source system, the DER and LOD were 2.94 and 1.36-mM CsOH, respectively. For the split-filter system, the DER and LOD were 1.41- and 6.11-mM CsOH, respectively. The signal on cesium maps in phantoms tracked linearly with concentration (R2  = 0.99) on both systems with an RMSE of 2.56 and 6.72 on the dual-source and split-filter system, respectively. In ex vivo models, CsOH was detected following delivery of TCA at all concentrations.

CONCLUSIONS

DECT can be used to detect and quantify the concentration of cesium in phantom and ex vivo tissue models. When incorporated in TCA, CsOH performs as a theranostic agent for quantitative DECT image-guidance.

Neoadjuvant Chemotherapy Followed by Radiofrequency Ablation May Be a New Treatment Modality for Colorectal Liver Metastasis: A Propensity Score Matching Comparative Study

Background: Most colorectal liver metastases (CRLM) are not candidates for liver resection. Radiofrequency ablation (RFA) plays a key role in selected CRLM patients. Neoadjuvant chemotherapy (NAC) followed by liver resection has been widely used for resectable CRLM. Whether NAC followed by radiofrequency ablation (RFA) can achieve a similar prognosis to NAC followed by hepatectomy remains is unclear. The present study aimed to provide a new treatment modality for CRLM patients. Methods: This comparative retrospective research selected CRLM patients from 2009 to 2022. They were divided into NAC + RFA group and NAC + hepatectomy group. The propensity score matching (PSM) was used to reduce bias. We used multivariate cox proportional hazards regression analysis to explore independent factors affecting prognosis. The primary study endpoint was the difference in the progression-free survival (PFS) between the two groups. Results: A total of 190 locally curable CRLM patients were in line with the inclusion criteria. A slight bias was detected in the comparison of basic clinical characteristics between the two groups. RFA showed a significant advantage in the length of hospital stay (median; 2 days vs. 7 days; p < 0.001). The 1- and 3-year PFS in the liver resection and the RFA groups was 57.4% vs. 86.9% (p < 0.001) and 38.8% vs. 55.3% (p = 0.035), respectively. The 1-year and 3-year OS in the liver resection and RFA groups was 100% vs. 96.7% (p = 0.191) and 73.8% vs. 73.6% (p = 0.660), respectively. Conclusions: NAC followed by RFA has rapid postoperative recovery, fewer complications, and better prognosis.

Single-session transarterial chemoembolization combined with percutaneous thermal ablation in liver metastases 3 cm or larger

PURPOSE

The purpose of this study was to evaluate the safety and efficacy of transarterial chemoembolization (TACE) combined with percutaneous thermal ablation in patients with liver metastases 3 cm in diameter or larger.

MATERIALS AND METHODS

This retrospective study included 39 patients with a total of 46 liver metastases treated. There were 14 men and 25 women, with a mean age of 55 ± 13.3 (SD) (age range: 28-77 years). All patients were treated with a combination of TACE and thermal ablation in a single session. Primary outcome was local tumor progression. Secondary outcomes were procedure related complications and systemic disease progression.

RESULTS

Mean tumor size was 3.6 ± 0.6 (SD) cm (range: 3-5 cm). Conventional TACE was performed in 32 liver metastases (32/46; 70%) and drug-eluting beads-TACE in 14 liver metastases (14/46; 30%) followed by radiofrequency ablation in 34 (34/46; 74%), microwave ablation in 11 (11/46; 24%) and cryoablation in one (1/46; 2%) metastasis. Four grade 2 (4/39; 10%) complications were observed. After a mean follow up of 31.9 ± 26.1 (SD) months (range: 2-113 months) overall local tumor progression rate was 15% (7/46). Local tumor progression rate at 12 months was 13% (6/46). Overall systemic disease progression was seen in 29 patients (29/39; 74%) with a systemic disease progression rate at 12 months of 59% (23/39).

CONCLUSION

Treatment of large liver metastases with TACE and thermal ablation in a single session is safe and achieves high local control rate.

Microwave Ablation, Radiofrequency Ablation, Irreversible Electroporation, and Stereotactic Ablative Body Radiotherapy for Intermediate Size (3-5 cm) Unresectable Colorectal Liver Metastases: a Systematic Review and Meta-analysis

Purpose of Review

Based on good local control rates and an excellent safety profile, guidelines consider thermal ablation the gold standard to eliminate small unresectable colorectal liver metastases (CRLM). However, efficacy decreases exponentially with increasing tumour size. The preferred treatment for intermediate-size unresectable CRLM remains uncertain. This systematic review and meta-analysis compare safety and efficacy of local ablative treatments for unresectable intermediate-size CRLM (3–5 cm).

Recent Findings

We systematically searched for publications reporting treatment outcomes of unresectable intermediate-size CRLM treated with thermal ablation, irreversible electroporation (IRE) or stereotactic ablative body-radiotherapy (SABR). No comparative studies or randomized trials were found. Literature to assess effectiveness was limited and there was substantial heterogeneity in outcomes and study populations. Per-patient local control ranged 22–90% for all techniques; 22–89% (8 series) for thermal ablation, 44% (1 series) for IRE, and 67–90% (1 series) for SABR depending on radiation dose.

Summary

Focal ablative therapy is safe and can induce long-term disease control, even for intermediate-size CRLM. Although SABR and tumuor-bracketing techniques such as IRE are suggested to be less susceptible to size, evidence to support any claims of superiority of one technique over the other is unsubstantiated by the available evidence. Future prospective comparative studies should address local-tumour-progression-free-survival, local control rate, overall survival, adverse events, and quality-of-life.

Percutaneous thermal ablation of hepatic tumors: local control efficacy and risk factors for artificial ascites failure

OBJECTIVE

To investigate the risk factors affecting the technical failure of artificial ascites (AA) formation and to evaluate the local control efficacy of percutaneous thermal ablation assisted by the AA for hepatic tumors.

METHODS

A total of 341 patients with 362 hepatic tumors who underwent thermal ablation assisted by AA were reviewed retrospectively. The technical success of AA, the volume of liquid, and local efficacy after ablation were assessed. Predictive factors for the technical failure of AA formation and local tumor progression (LTP) were analyzed using univariate and multivariate analysis.

RESULTS

The technical success rate of AA formation was 81.8% (296/362). The amount of fluid was higher when the tumor was located in the left lobe of the liver than when it was located in the right lobe (median 950 ml versus 700 ml, p < 0.001). Previous hepatic resection (OR: 12.63, 95% CI: 2.93-54.45, p < 0.001), ablation (OR: 6.48, 95% CI: 1.36-30.92, p = 0.019) and upper-abdomen surgery (OR: 11.34, 95% CI: 1.96-65.67, p = 0.007) were the independent risk factors of AA failure. In the AA success group, the complete ablation rate was higher and the LTP rate was lower than that in the AA failure group (98.7 versus 92.4%, p = 0.012; 8.8 versus 21.2%, p = 0.004). Multivariate analysis identified AA failure (p = 0.004), tumor size (>3.0 cm) (p = 0.002) and metastatic liver tumor (p = 0.008) as independent risk factors for LTP.

CONCLUSION

History of hepatic resection, ablation and upper abdomen surgery were significant predictive factors affecting the technical failure of AA formation. Successful introduction of AA before thermal ablation can achieve better local tumor control efficacy.

Advances in Diagnostic and Interventional Radiology in Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths, and radiological imaging and locoregional therapies are essential for the management of patients with HCC.

SUMMARY

In cirrhotic patients, a characteristic imaging pattern establishes the noninvasive diagnosis of HCC with acceptable sensitivity and high specificity. In addition to diagnosis, imaging is used in the staging of patients and treatment allocation. Multiparametric MRI with hepatospecific contrast agents improves lesion detection, characterization, and treatment allocation; recently described imaging criteria allow identification of precursor lesions. Radiofrequency ablation (RFA) and transarterial chemoembolization (TACE) have been established in the treatment of patients with HCC at the early and intermediate stages, respectively. Microwave ablation has been described as an alternative to RFA in selected cases. Imaging-guided brachytherapy, a catheter-based radiotherapy technique, offers advantages to overcome some limitations of the aforementioned therapies, including the tumor location and size. Currently, no adjuvant therapy is recommended after RFA or TACE, but several new drugs are under evaluation. Furthermore, although the exact role of selective internal radiation therapy (SIRT) in HCC still needs to be defined, it is an alternative to systemic agents in patients with intolerance, and additional benefit has been shown in selected subgroups. Additionally, SIRT offers an alternate to TACE with higher objective response rates in patients who needs bridging before transplantation.

KEY MESSAGES

New imaging criteria improved lesion detection in patients at a risk for HCC, and advances in interventional therapies expanded the range of patients eligible for locoregional treatments.

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.

Novel swine biliary dilatation model with temperature-controlled endobiliary radiofrequency ablation: An effective tool for training in EUS-guided biliary drainage

Background and Objectives:

EUS-guided biliary drainage (EUS-BD) is used as a rescue method after failed endoscopic retrograde cholangiography. However, it is considered a technically challenging procedure. Phantoms and ex vivo biliary dilatation models have been used to enhance the learning of EUS-BD, but they provide a limited level of realism. The aim of this study was to develop a swine biliary dilatation model that uses temperature-controlled endobiliary radiofrequency ablation (EB-RFA) for training in EUS-BD.

Materials and Methods:

Target temperature-controlled (80°C at 7 or 10 W for 60–120 s) EB-RFA was performed on seven pigs. Two weeks after the EB-RFA, EUS examination was performed to confirm biliary dilatation, and EUS-BD was then attempted by performing a hepaticogastrostomy (HGS) or cholecystogastrostomy (CGS).

Results:

Twelve sessions of EB-RFA (11 at the distal common bile duct [CBD] and one at the proximal CBD) were successfully performed on the seven pigs. There were no immediate postprocedural adverse events. Two weeks after the procedures, clinical signs of jaundice were observed in all the pigs. EUS examination revealed massive intrahepatic and extrahepatic biliary dilatations in all the pigs, and EUS-BD was attempted in the same session. HGS was performed on six pigs. Technical success was achieved in five of the six pigs (83.3%). Technical failure in HGS occurred during the stent deployment, and CGS was successfully performed on one pig.

Conclusions:

Our study shows that EB-RFA is an effective minimally invasive method for creating biliary dilatation models. It may be considered suitable for training in EUS-BD.

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.

Predictive factors of treatment outcomes after percutaneous ablation of hepatocellular carcinoma in the caudate lobe: a retrospective study

Background

Hepatocellular carcinomas (HCC) arising in the caudate lobe is rare and the treatment is difficult. The aim of this study is to summarize the experience of ultrasound-guided percutaneous ablation therapy for HCC located in the caudate lobe and to investigate the predictive factors of the treatment outcomes.

Methods

From August 2006 to June 2017, 73 patients (63 males and 10 females; mean age, 54.9 ± 11.6 years; age range, 25–79 years) with 73 caudate lobe HCCs (mean size, 2.6 ± 1.1 cm; size range, 1.0–5.0 cm) were treated with percutaneous ablation, including 33 patients with radiofrequency ablation (RFA), 23 patients with ethanol ablation (EA), and 17 patients with combination of RFA and EA. The treatment outcome and survival after ablation for caudate lobe HCC were assessed and the predictive factors were calculated by univariate and multivariate analyses.

Results

A total of 72 patients achieved complete ablation after the first or second session of ablation. The treatment effectiveness was 98.6% (72/73). During the follow-up, 16 tumors developed local tumor progression (LTP) and a total of 61 patients (61/73, 83.6%) were detected distant recurrence (DR). According to univariate and multivariate analyses, tumor size > 2 cm (hazard ratio[HR] = 3.667; 95% confidence interval[CI], 1.043–12.889; P = 0.043) was a significant prognostic factor of LTP after ablation for HCC in the caudate lobe, while tumor number (HR = 2.245; 95%CI, 1.168–4.317; P = 0.015) was a significant prognostic factor of DR. The mean overall survival time after ablation was 28.7 ± 2.8 months, without independent predictive factors detected. Four patients (4/73, 5.5%) were detected treatment-related major complications, without independent predictive factor detected.

Conclusion

Ultrasound-guided percutaneous ablation is a feasible treatment for a selected case with HCC in the caudate lobe. Tumor size > 2 cm increases the risk of LTP and intrahepatic tumor number is associated with DR after ablation.

Radiofrequency and malignant biliary strictures: An update

Malignant biliary strictures are usually linked to different types of tumors, mainly cholangiocarcinoma, pancreatic and hepatocellular carcinomas. Palliative measures are usually adopted in patients with nonresectable or borderline resectable biliary disease. Stent placement is a well-known and established treatment in patients with unresectable malignancy. Intraductal radiofrequency ablation (RFA) represents a procedure that involves the use of a biliary catheter device, via an endoscopic approach. Indications for biliary RFA described in literature are: Palliative treatment of malignant biliary strictures, avoiding stent occlusion, ablating ingrowth of blocked metal stents, prolonging stent patency, ablating residual adenomatous tissue after endoscopic ampullectomy. In this mini-review we addressed focus on technical success defined as deployment of the RF catheter, virtually succeeded in all patients included in the studies. About efficacy, three main outcome measures have been contemplated: Biliary decompression and stent patency, survival. Existing studies suggest a beneficial effect on survival and stent patency with RFA, but current impression is limited because most of studies have been performed using a retrospective design, on diminutive and dissimilar cohorts of patients.

Long-term outcomes and prognostic analysis of percutaneous radiofrequency ablation in liver metastasis from breast cancer

OBJECTIVE

To evaluate the long-term efficacy and prognostic factors of ultrasound-guided percutaneous radiofrequency ablation (RFA) for breast cancer liver metastasis (BCLM).

METHODS

Between 2000 and 2015, 69 patients who underwent ultrasound-guided percutaneous RFA for BCLM and had regular follow-up examinations were included. All patients had undergone resection of the primary breast cancer and had received chemotherapy, endocrine therapy or both after surgery. The sample included two males and 67 females with an average age of 50.3 ± 10.0 years (31-76 y). The mean maximum diameter of metastatic lesions in the liver was 2.9 ± 1.4 cm (1.0-6 cm). Thirty-five patients had a single metastasis, while 34 patients had multiple liver metastases (2-5 lesions). Survival results were generated using Kaplan-Meier estimates and a multivariate analysis was performed using the Cox regression model.

RESULTS

In total, 92 RFA sessions were performed and 135 BCLM lesions were treated. Major complications occurred in one of the 92 sessions (1.1%). Technical efficacy was achieved in 92.6% of lesions (125/135 lesions). Local tumor progression occurred in 11.6% (8/69) of patients and new intrahepatic metastasis occurred in 55.1% (38/69) of patients. From the time of initial RFA, the median overall survival was 26 months, and the one-, two-, three- and five -year survival rates were 81.8, 50.1, 25.3 and 11.0%, respectively. Based on the multivariate analysis, the following three factors were identified as independent prognostic factors for overall survival: tumor size (p = .017), positive estrogen receptor status (p = .009) and extrahepatic metastatic disease (p = .001). The median progression-free survival was 24 months, and the one-, two-, three- and five -year survival rates after RFA were 77.4, 47.0, 23.7 and 8.5%, respectively. Additionally, the independent prognostic factors for progression-free survival included tumor size (p = .011), ER positivity (p = .001), margin size (p = .017) and extrahepatic metastatic disease (p < .001).

CONCLUSION

The results of this study showed that RFA is a safe and locally effective method for the treatment of BCLM, especially in patients with lesions measuring less than 3 cm in diameter, a single liver metastasis, positive estrogen receptor status and no extrahepatic metastases. Also, patients with margin size >10 mm had no local tumor progression.

Local recurrence rate in patients with colorectal cancer liver metastasis after wedge resection or percutaneous radiofrequency ablation

PURPOSE

To compare local recurrence (LR) rate in patients with colorectal cancer liver metastasis (CRCLM) after surgical wedge resection (WR) or radiofrequency ablation (RFA) and to investigate predictive factors of LR.

MATERIALS AND METHODS

This single-centre, retrospective, institutional review board-approved study including 43 consecutive patients with 121 metastases treated by WR and 60 patients with 110 metastases treated by RFA between 2007 and 2014 with 23 and 18.5 months of follow-up, respectively. Demographics and tumour characteristics were compared using the unpaired t-test and chi-square test. Predictive factors for LR (lesion size, depth, relation to hepatic vessels, intervention, margin status) were investigated in uni- and multivariate analyses.

RESULTS

Patient and CRCLM characteristics were similar in both groups. Mean lesion size and depth in the WR and RFA groups were 18 mm and 15 mm (p = 0.03), and 19 mm and 26 mm (p < 0.001), respectively. LR showed a trend towards difference in favour of RFA (19% and 10% in the WR and RFA groups, respectively, p = 0.06). Positive margins and lesion depth were predictive factors of LR in the WR group (p = 0.03 and p = 0.02, respectively, on uni- and multivariable analyses). Lesion depth and proximity to a vein increased the risk of positive margins on pathology after WR (p = 0.04 and p < 0.001, respectively). Our analysis did not identify any predictive factors of LR following RFA.

CONCLUSION

Our study showed a trend towards a lower LR rate with RFA compared to WR. Lesions located deep in the liver and/or close to large vessels are at high risk of LR following WR, while curative treatment can be obtained with RFA.

A prognostic nomogram for colorectal cancer liver metastases after percutaneous thermal ablation

PURPOSE

To assess the efficacy of percutaneous thermal ablation in treating colorectal cancer liver metastases (CRCLM), and to propose a prognostic nomogram for overall survival (OS).

MATERIALS AND METHODS

Seventy-one patients with CRCLM undergoing thermal ablation at our institute from 2009 to 2013 were identified and analysed to formulate a prognostic nomogram. The concordance index (C-index) and calibration curve were calculated to evaluate the predictive accuracy of the nomogram. The nomogram was compared with two current prognostic nomograms for patients with CRCLM who had undergone hepatectomy (Kattan) and selective internal radiation therapy (Fendler). Predictive validity was assessed in the validation cohort of 25 patients who had undergone thermal ablation from 2014 to 2016.

RESULTS

The median OS in the primary cohort was 26.4 months, whereas the 1-, 3- and 5-year OS rates were 72.2%, 37.2% and 17%, respectively. The median progression-free survival was 4.2 months. After univariate and multivariate analysis, a prognostic nomogram was formulated based on four predictors, including the number of tumours, maximum diameter of the tumour, CA19-9 level and ablation margin. The C-index of the nomogram was 0.815. Based on the patients of this study, the C-index was significantly higher than that of the Fendler nomogram (C-index, 0.698) and Kattan nomogram (C-index, 0.514, p < 0.001). Predictive accuracy of the proposed nomogram was also satisfactory in the validation cohort, with a C-index of 0.884.

CONCLUSIONS

Thermal ablation was an effective therapy for CRCLM. Moreover, the nomogram was effective and simple for CRCLM patients undergoing thermal ablation.

Percutaneous CT-guided radiofrequency ablation for patients with extrahepatic oligometastases of hepatocellular carcinoma: long-term results

BACKGROUND

The aim of this study was to evaluate the therapeutic outcome of percutaneous computed tomography (CT)-guided radiofrequency ablation (RFA) for extrahepatic oligometastases of hepatocellular carcinoma (HCC).

METHODS

Institutional review board approval was obtained for this retrospective study, and all patients provided written informed consent. Between April 2004 and December 2015, 116 oligometastases (diameter, 5-50 mm; 20.3 ± 10.4) in 79 consecutive HCC patients (73 men and 6 women; average age, 50.3 years ±13.0) were treated with RFA. We focussed on patients with 1-3 extrahepatic metastases (EHM) confined to 1-2 organs (including the lung, adrenal gland, bone, lymph node and pleura/peritoneum) who were treated naïve with curative intent. Survival, technical success and safety were evaluated. The log-rank test and Cox proportional hazards regression models were used to analyse the survival data.

RESULTS

No immediate technical failure occurred, and at 1 month, the technique effectiveness rate was determined to be 95.8%. After a median follow-up time of 28.0 months (range, 6-108 months), the 1-, 2- and 3-year overall survival (OS) rates were 91, 70 and 48%, respectively, with a median survival time of 33.5 months. Time to unoligometastatic progression (TTUP) of less than 6 months (p < 0.001) and a Child-Pugh score of more than 5 (p = 0.001) were significant indicators of shorter OS. The 1-, 2- and 3-year disease free survival (DFS) rates were 34, 21 and 8%, respectively, with a median DFS time of 6.8 months. DFS was better for those with lung metastases (p = 0.006). Major complication occurred in nine (9.5%, 9/95) RFA sessions without treatment-related mortality.

CONCLUSIONS

CT-guided RFA for oligometastatic HCC may provide favourable efficacy and technical success with a minimally invasive approach.

Comparison of intraluminal radiofrequency ablation and stents vs. stents alone in the management of malignant biliary obstruction

PURPOSE

To retrospectively evaluate the added benefit of adding intraluminal radiofrequency ablation (RFA) to biliary metal stent placement for patients with malignant biliary obstruction (MBO).

METHODS

From November 2013 to December 2015, 89 patients with MBO who had undergone percutaneous intraluminal RFA and stent placement (RFA-stent group, n = 50) or stent placement only (stent group, n = 39) were included. Outcomes were compared according to the type of tumour: cholangiocarcinoma or non-cholangiocarcinoma.

RESULTS

Primary and secondary stent patency (PSP, SSP) were significantly higher for the RFA-stent group than the stent group (PSP: 7.0 months vs. 5.0 months, p = 0.006; SSP: 10.0 months vs. 5.6 months, p < 0.001), with overall survival being comparable (5.0 months vs. 4.7 months, p = 0.068). In subgroup analysis, RFA-stent showed significant PSP benefits compared to stent alone in patients with cholangiocarcinoma (7.4 months vs. 4.3 months; p = 0.009), but with comparable outcomes in patients with non-cholangiocarcinoma (6.3 months vs. 5.2 months; p = 0.266). The SSP was improved in both subgroups (cholangiocarcinoma, 12.6 months vs. 5.0 months, p < 0.001; non-cholangiocarcinoma, 10.3 months vs. 5.5 months, p = 0.013). Technical success and clinical success were not significantly different between the two groups. The rate of complication was higher for the RFA-stent group, but tolerable when compared to the stent group.

CONCLUSIONS

Although survival was comparable between the groups, RFA-stent confers therapeutic benefits to patients with MBO in terms of stent patency compared to stent placement alone, especially in those with cholangiocarcinoma.