Radiofrequency and microwave ablation of subcapsular hepatocellular carcinoma accessed by direct puncture: Safety and efficacy

Bipolar radiofrequency track cautery during abdominal biopsies: teaching points and lessons learned

Abdominal percutaneous needle biopsies are commonly performed minimally invasive procedures to obtain tissue samples for histopathological diagnosis. Severe post-biopsy bleeding is uncommon but can be associated with prolonged hospitalization, additional interventions, morbidity, and death. Many factors may increase bleeding risk and various peri-procedural and intra-procedural strategies may minimize bleeding risk. Bipolar radiofrequency track cautery is one method that may reduce the risk of post-biopsy bleeding or tumor seeding. This paper offers an illustrative case-based review of teaching points and lessons learned in our experience using a commercially available bipolar radiofrequency track cautery device during percutaneous image-guided abdominal biopsies.

Imaging Classification of Exophytic HCC and Our Experience with Microwave Ablation of Type 2 Lesions

Purpose  The purpose of this article is to classify hepatocellular carcinoma (HCC) based on imaging and to evaluate the role of ultrasound-guided microwave ablation (MWA) in the management of type 2 exophytic HCC. Materials and Methods  A retrospective study was performed at our institution after approval by the Institutional Review Board. The study was undertaken from January 2017 to May 2022. Based on the location, HCC was classified and categorized on cross-sectional imaging into four types. All MWA procedures were performed using ultrasound guidance. Patients were followed up every 3 months with cross-sectional imaging. Results  During the study period, 225 lesions were reviewed. MWA was performed in 13 type 2 exophytic HCC patients. Segment 3 (38%) was the most common site when categorized as per Couinaud classification and segment 6 was the next common site. Technical success of complete ablation, evaluated by postprocedure contrast-enhanced computed tomography scan, was 100%. The median follow-up period was 24 months (range: 9-24 months). One patient presented with a residual lesion on the first follow-up at 30 days. Two other patients followed up to 9 months were free of HCC. Ten patients followed up at 1 year showed no recurrence, while 7 of them were followed up for 24 months, and 1 of whom showed multicentric recurrence which was treated by selective intra-arterial radiation therapy. Conclusion  A classification system for exophytic lesions can allow for better patient selection, planning, and reporting of ablative outcomes. MWA has performed well when ablating these technically challenging lesions with a certain degree of planning.

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.

Diagnostic Management of Gastroenteropancreatic Neuroendocrine Neoplasms: Technique Optimization and Tips and Tricks for Radiologists

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) comprise a heterogeneous group of neoplasms, which derive from cells of the diffuse neuroendocrine system that specializes in producing hormones and neuropeptides and arise in most cases sporadically and, to a lesser extent, in the context of complex genetic syndromes. Furthermore, they are primarily nonfunctioning, while, in the case of insulinomas, gastrinomas, glucagonomas, vipomas, and somatostatinomas, they produce hormones responsible for clinical syndromes. The GEP-NEN tumor grade and cell differentiation may result in different clinical behaviors and prognoses, with grade one (G1) and grade two (G2) neuroendocrine tumors showing a more favorable outcome than grade three (G3) NET and neuroendocrine carcinoma. Two critical issues should be considered in the NEN diagnostic workup: first, the need to identify the presence of the tumor, and, second, to define the primary site and evaluate regional and distant metastases. Indeed, the primary site, stage, grade, and function are prognostic factors that the radiologist should evaluate to guide prognosis and management. The correct diagnostic management of the patient includes a combination of morphological and functional evaluations. Concerning morphological evaluations, according to the consensus guidelines of the European Neuroendocrine Tumor Society (ENETS), computed tomography (CT) with a contrast medium is recommended. Contrast-enhanced magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI), is usually indicated for use to evaluate the liver, pancreas, brain, and bones. Ultrasonography (US) is often helpful in the initial diagnosis of liver metastases, and contrast-enhanced ultrasound (CEUS) can solve problems in characterizing the liver, as this tool can guide the biopsy of liver lesions. In addition, intraoperative ultrasound is an effective tool during surgical procedures. Positron emission tomography (PET-CT) with FDG for nonfunctioning lesions and somatostatin analogs for functional lesions are very useful for identifying and evaluating metabolic receptors. The detection of heterogeneity in somatostatin receptor (SSTR) expression is also crucial for treatment decision making. In this narrative review, we have described the role of morphological and functional imaging tools in the assessment of GEP-NENs according to current major guidelines.

Management of adreno-cortical adenomas using microwave ablation: study of the effects of the fat tissue

BACKGROUND AND OBJECTIVES

Adrenocortical neoplasms are the main causes of secondary hypertension and related comorbidities including hypokalemia and cardiovascular diseases. Conventional techniques for the management of this condition are often invasive and not resolutive. Recent studies proposed microwave thermal ablation (MWA) to eradicate adrenocortical adenomas arising in proximity to sensitive structures. This study explores a new MWA approach to selectively direct the electromagnetic energy into the target and shield the surrounding tissues. The new solution relies on the anatomical and dielectric characteristics of the adrenal gland and the surrounding fat capsule.

METHODS

A 3 D model of the adrenal gland is developed, and a cooled microwave applicator is placed parallel to the interface between the fat and adrenal tissue. Numerical simulations are conducted at 2.45 GHz accounting for two energy delivery settings, two orientations of the applicator and blood perfusion of the tissues. Ex vivo and in vivo ablation procedures are conducted on ovine adrenal glands. Histology analysis completes the experimental studies.

RESULTS

Numerical results show asymmetric ablation profiles in ex vivo and in vivo conditions. The asymmetry ratio is influenced by the procedure settings and orientation of the applicator. Ablation zones obtained experimentally agree with those predicted by the numerical simulations. Histology analysis confirms irreversible cellular changes only in the adrenal tissue close to the applicator.

CONCLUSIONS

The outcomes show that the dielectric contrast between the fat layer and tissue target can be a tool in MWA to shape ablation zones to protect the surrounding structures from excessive temperature increases.

Risk of intra-abdominal seeding after laparoscopic-assisted thermal ablation of exophytic hepatocellular carcinoma tumors

BACKGROUND

Laparoscopic-assisted thermal ablation has been used successfully to treat early hepatocellular carcinoma (HCC) tumors, defined as < 3 cm in diameter. This approach allows for ablation of tumors located in areas of the liver that are otherwise inaccessible for a percutaneous approach. Thermal ablation of exophytic tumors remains controversial due to a reported increased risk of tumor seeding of the abdominal cavity and incomplete ablation.

METHODS

This cohort study consisted of 663 HCC tumors treated with thermal ablation at a single, quaternary academic medical center between 2/2001 and 1/2021. Post treatment, patients were followed at a defined interval schedule beginning at one month post treatment, then every 3 months for 2 years, every 6 months in year 3, followed by yearly studies. Patients' medical records were reviewed for three years post ablation for evidence of complete ablation and intra-abdominal dissemination of disease.

RESULTS

326 patient records met the inclusion criteria. Comparing the exophytic and non-exophytic groups, there were statistically significant differences in etiology of liver disease (p = 0.048) and TNM stage (p = 0.03), as well as a higher rate of incomplete ablation in the non-exophytic group (10.2% vs 3.3%; p = 0.045). Otherwise, there were no statistically significant differences in baseline characteristics, tumor characteristics, or use of thermal ablation technology. Rates of intra-abdominal dissemination of HCC were low in both groups: 1.1% (n = 1) in the exophytic group and 1.7% (n = 4) in the non-exophytic group. There was no significant difference in intra-abdominal dissemination of HCC between the groups (p > 0.99, RR = 0.66; 95% CI 0.07-5.79). Additionally, no differences were seen in dissemination between microwave ablation and radiofrequency ablation (p > 0.99).

CONCLUSION

This study demonstrates that laparoscopic-assisted thermal ablation of small, exophytic tumors is safe and does not increase the risk for disseminated intra-abdominal HCC disease.

Microwave versus radiofrequency ablation for the treatment of liver malignancies: a randomized controlled phase 2 trial

Microwave (MWA) and radiofrequency ablation (RFA) are main ablative techniques for hepatocellular carcinoma (HCC) and colorectal liver metastasis (MT). This randomized phase 2 clinical trial compares the effectiveness of MWA and RFA as well as morphology of corresponding ablation zones. HCC and MT patients with 1.5–4 cm tumors, suitable for ablation, were randomized into MWA or RFA Groups. The primary endpoint was short-to-long diameter ratio of ablation zone (SLR). Primary technical success (TS) and a cumulative local tumor progression (LTP) after a median 2-year follow-up were compared. Between June 2015 and April 2020, 82 patients were randomly assigned (41 patients per group). For the per-protocol analysis, five patients were excluded. MWA created larger ablation zones than RFA (p = 0.036) although without differences in SLR (0.5 for both groups, p = 0.229). The TS was achieved in 98% (46/47) and 90% (45/50) (p = 0.108), and LTP was observed in 21% (10/47) vs. 12% (6/50) (OR 1.9 [95% CI 0.66–5.3], p = 0.238) of tumors in MWA vs. RFA Group, respectively. Major complications were found in 5 cases (11%) vs. 2 cases (4%), without statistical significance. MWA and RFA show similar SLR, effectiveness and safety in liver tumors between 1.5 and 4 cm.

Image-guided locoregional non-intravascular interventional treatments for hepatocellular carcinoma: Current status

Hepatocellular carcinoma (HCC) is one of the most deadly and frequent cancers worldwide, although great advancement in the treatment of this malignancy have been made within the past few decades. It continues to be a major health issue due to an increasing incidence and a poor prognosis. The majority of patients have their HCC diagnosed at an intermediate or advanced stage in theUSA or China. Curative therapy such as surgical resection or liver transplantation is not considered anoption of treatment at these stages.

Transarterial chemoembolization (TACE), the most widely used locoregional therapeutic approach, used to be the mainstay of treatment for cases with unresectable cancer entities. However, for those patients with hypovascular tumors or impaired liver function reserve, TACE is a suboptimal treatment option. For example, embolization does not result in complete coverage of a hypovascular tumor, and may rather promotes postoperative tumor recurrence, or leave residual tumor, in these TACE-resistance patients. In addition, TACE carries a higher risk of hepatic decompensation in patients with poor liver function or reserve.

Non-vascular interventional locoregional therapies for HCC include radiofrequency ablation (RFA), microwave ablation (MWA), high-intensity focused ultrasound (HIFU), laser-induced thermotherapy (LITT), cryosurgical ablation (CSA), irreversible Electroporation (IRE), percutaneous ethanol injection (PEI), and brachytherapy. Recent advancements in these techniques have significantly improved the treatment efficacy of HCC and expanded the population of patients who qualify for treatment. This review embraces the current status of imaging-guided locoregional non-intravascular interventional treatments for HCCs, with a primary focus on the clinical evaluation and assessment of the efficacy of combined therapies using these interventional techniques.

Radiofrequency versus microwave ablation for hepatocellular carcinoma within the Milan criteria in challenging locations: a retrospective controlled study

PURPOSE

The aim of this study was to compare the safety and efficacy of radiofrequency ablation (RFA) with microwave ablation (MWA) for hepatocellular carcinoma (HCC) within the Milan criteria in challenging locations.

METHODS

This study retrospectively investigated 201 consecutive patients with Milan criteria HCCs who underwent RFA (RFA group, n = 150) or MWA (MWA group, n = 51) between January 2012 and December 2016. Overall survival (OS), recurrence-free survival (RFS), local tumor control, and treatment-related complications were compared between the two groups. Prognostic factors were analyzed using the Cox proportional hazard regression model.

RESULTS

Median follow-up duration was 36.7 months (range: 6.2-64.0 months). Cumulative 1-, 3-, and 5-year OS rates were 97.9%, 92.3%, and 80.6% in the MWA group and 96.4%, 87.4%, and 78.2% in the RFA group, respectively, (P = 0.450). Cumulative RFS rates at 1, 3, and 5 years were 93.2%, 74.4%, and 63.7% in the MWA group and 80.3%, 57.3%, and 49.6% in the RFA group, respectively, (P = 0.097). Multivariate analyses showed that variable categories "patient age above 65 years" (P = 0.004) and "more than one tumor" (P = 0.004) were associated with overall mortality, and "patient age above 65 years" (P = 0.048) and "tumor size greater than 3 cm" (P = 0.009) were associated with inferior RFS. The incidences of major complications were not significantly different between the two groups (3.3% vs 3.9%, P = 0.843).

CONCLUSIONS

RFA and MWA were associated with comparable safety and efficacy for HCC within the Milan criteria in challenging locations. Further study in a large, multi-center patient cohort is necessary to validate the results.

Comparison of Percutaneous Radiofrequency Ablation for Subcapsular and Non-Subcapsular Colorectal Cancer Liver Metastases

Purpose

To evaluate the efficacy and safety of percutaneous radiofrequency ablation (RFA) for subcapsular colorectal cancer liver metastases (CLMs).

Materials and Methods

With the approval of the Institutional Review Board, the clinical data of CLM patients who underwent percutaneous RFA for the first time from August 2010 to August 2020 were continuously collected. All CLMs were divided into subcapsular and non-capsular groups. Baseline characteristic data, technical effectiveness, minimal ablative margin, complications, local tumor progression (LTP), and overall survival (OS) between the two groups were analyzed using the t-test or chi-square test. A Cox regression model was used to evaluate the prognostic factors of LTP.

Results

One hundred and ninety-nine patients (124 males; mean age, 60.2 years) with 402 CLMs (221 subcapsular; mean size, 16.0 mm) were enrolled in the study. Technical effectiveness was achieved in 93.5% (376/402) of CLMs, with a major complication rate of 5.5%. Compared with non-subcapsular tumors, the minimal ablative margin achieved in subcapsular CLM was smaller (χ² = -8.047, P < 0.001). With a median follow-up time of 23 months (range, 3−96 months), 37.1% of the tumors had LTP. The estimated cumulative OS at 1, 3, and 5 years was 96.1%, 66.0%, and 44.2%, respectively. There were no statistically significant differences between the two groups in terms of technical effectiveness (χ² = 0.484, P = 0.487), major complications (χ² = 0.082, P = 0.775), local tumor progression-free survival (LTPFS) (χ² = 0.881, P = 0.348), and OS (χ² = 2.874, P = 0.090). Minimal ablative margin, tumor size (≥20 mm), and technical effectiveness were predictors of LTP (all P < 0.05).

Conclusion

RFA is a safe and effective technique for local tumor control of subcapsular CLMs.

Efficacy and safety of percutaneous microwave ablation for hepatocellular carcinomas <4 cm in difficult location

OBJECTIVE

Tumor location is a critical factor for determining technical success and local recurrence following percutaneous ablation of hepatocellular carcinomas (HCC). The purpose of this retrospective study was to evaluate the safety and outcome measures of percutaneous microwave ablation (pMWA) for HCCs <4 cm in difficult locations.

METHODS

Retrospective review included 81 patients who underwent pMWA for HCCs <4 cm. Fourty-three patients (30 males and 13 females; mean age, 61 years) with 53 HCCs located near the diaphragm, heart, gallbladder, kidney, gastrointestinal tract, large vessel and exophytic location were included under difficult location group. Thirty-eight patients (29 males and nine females; mean age, 60 years) with 48 HCCs in other locations were included under control group. Baseline demographics were recorded. Technical efficacy, local tumor progression (LTP), and complication rates were evaluated.

RESULTS

Mean follow-up period was 3.4 months (range 1-7). There was no major complication in both the groups; two patients had a mild perihepatic hemorrhage in the difficult location group which was managed conservatively. There was no difference between the groups in the overall technical efficacy rate (84.9% vs 91.7%, p = 0.294), LTP rate (4.4% vs 2.2%. p = 0.57) or complication rate (4.6% vs 0%, p = 0.177).

CONCLUSION

Our data suggest that there is no significant difference in technical efficacy, LTP or complication rates for MWA in both difficult and normal locations.

ADVANCES IN KNOWLEDGE

With proper patient selection, pre-procedural planning and appropriate technique, pMWA is feasible, safe, and effective for small HCCs in difficult location with an acceptable range of complications.

Percutaneous cryoablation of subcapsular hepatocellular carcinoma: a retrospective study of 57 cases

PURPOSE This study aims to evaluate the safety and effectiveness of the percutaneous cryoablation for subcapsular hepatocellular carcinoma (HCC). METHODS A total of 57 patients with subcapsular (<1 cm form the liver edge) HCCs (68 lesions), who were treated with CT-guided percutaneous cryoablation in the Department of Interventional Radiology of our hospital between July 1, 2016 and September 1, 2018, were retrospectively included. Complete ablation rate, local tumor progression (LTP) and treatment-related complications were evaluated. Furthermore, the degree of intraoperative and postoperative pain was measured with the visual analog scale (VAS), and laboratory findings were compared before and after the procedure. RESULTS All patients successfully completed the treatment. The mean follow-up period was 12.8 months (range, 3-27 months), and the complete ablation rate was 97% (66/68). Local tumor progression occurred in 11 lesions (16.2%), and the 6-, 12- and 18-month cumulative LTP rates were 4.0%, 8.2% and 20.5%, respectively. Two patients (3.5%, 2/57) developed major complications, and 12 patients had minor complications (22.8%, 12/57). The mean VAS score during the operation was 1.65 points (range, 1-3 points). Postoperative pain worsened in 3 patients, and the VAS scores reached 4-5. Transient changes in biochemical and hematologic markers were observed. CONCLUSION Percutaneous cryoablation for subcapsular HCC is safe and effective, the procedure is simple and the patients suffer less pain.

Risk of needle tract seeding after coaxial ultrasound-guided percutaneous biopsy for primary and metastatic tumors of the liver: report of a single institution

Purpose

The objective of this study was to determine the incidence of needle track seeding after ultrasound-guided percutaneous biopsy of indeterminate liver lesions with a coaxial biopsy system without any other additional intervention or ablation therapy.

Methods

We identified 172 patients in a retrospective cohort study who underwent ultrasound-guided biopsy due to a liver mass in our institution between 2007 and 2016. The same coaxial biopsy system was used in all patients, no consecutive ablation was performed.

Results

None of the finally included 131 patients developed neoplastic seeding. There was one major complication (0.76%), the rest of the complications were minor (3.8%) and did not require further intervention.

Conclusion

Needle track seeding is a rare delayed complication after percutaneous liver biopsy. Coaxial liver biopsy is a safe method to obtain multiple samples with a single punch in patients with primary or metastatic liver lesions.

Outcome of Laparoscopic Assisted Percutaneous Microwave Ablation for Exophytic Versus Non-exophytic Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignancies and is the third cause of cancer-related death worldwide. Surgery is the optimal treatment for early HCC; however, the majority of cases are not suitable for curative resection at the time of diagnosis. Surgical resection difficulties may be related to size, site, number of tumors, extrahepatic involvement, and patient general condition. Exophytic tumors were considered as relative contraindication for thermal ablation because of the risk of incomplete ablation or major complications as hemorrhage and seeding.

AIM OF THIS STUDY

to evaluate the safety and efficacy of microwave ablation (MWA) of exophytic HCC in comparison with non-exophytic HCC.

METHODS

Prospective comparative study carried on 30 patients having 30 exophytic (six of those patients had another non-exophytic lesion) and 32 patients having 44 non-exophytic HCC lesions (22 had single lesion, 8 patients had 2 lesions, and 2 patients had 3 lesions) within Milan criteria. All patients were child A or B, they were subjected to full clinical assessment, laboratory investigations, and radiological investigations. Laparoscopic assisted percutaneous MWA was the procedure of choice in our study for all patients either having exophytic or non-exophytic lesions using no-touch wedge technique for exophytic lesions and direct puncture for non-exophytic lesions.

RESULTS

Technical success was 100% in both groups, all lesions were completely ablated as confirmed by LIOUS. There were no major complications or perioperative mortality and low incidence of local tumor progression in both exophytic and non-exophytic groups.

CONCLUSION

Laparoscopic assisted MWA of exophytic HCC is safe and effective with comparable results to non-exophytic HCC. Exophytic HCC is not contraindication for MWA with proper technique selection.

Ablation for hepatocellular carcinoma: beyond the standard indications

Hepatocellular carcinoma (HCC), the most common primary liver neoplasia, represents the fifth most common malignant disease in men. Percutaneous ablation treatment is recommended among the treatments suggested for HCC patients in the very early/early stage. In the last decade, very important results in terms of survival benefits have been obtained with local ablative therapies, also outside the standard indications, thanks to many technical innovations. In particular, important results of ablation as a safe and effective technique have been obtained in the treatment of intermediate- or advanced-stage patients with HCC, and in the treatment of unfavourable tumour locations. Moreover, awareness is growing regarding the necessity of overcoming the rigidity of traditional guidelines in the treatment of HCC due to the complexity of patients with HCC, focusing on Precision Medicine. In this context, it is important to know the standard and non-standard indications of ablation in the treatment of HCC in order to offer the best therapeutic option tailored for each patient. The aim of this study was to analyse the possible clinical applications of ablative therapies for HCC patients, beyond the traditional indications recommended in the most widespread clinical practice guidelines for the management of HCC.

Percutaneous thermal ablation of subcapsular hepatocellular carcinomas: influence of tumor-surface contact and protrusion on therapeutic efficacy and safety

PURPOSE

To evaluate therapeutic efficacy and complication of percutaneous thermal ablation of subcapsular hepatocellular carcinomas (HCCs), and how these may be influenced by the degree of tumor to liver surface contact and tumor protrusion from liver surface.

MATERIALS AND METHODS

Our retrospective study was approved by the Institutional Review Board. Between January 2006 and December 2013, 290 patients (82 women, 208 men; mean age, 64.5 years; range, 33-89 years) with 474 subcapsular (within 1 cm to the liver surface) HCCs (mean size, 23.7 mm; range, 6-71 mm) underwent percutaneous thermal ablation. The HCCs were divided into surface contact group (n = 243) and non-surface contact group (n = 231). The former was further subdivided into exophytic and non-exophytic HCCs. Technical success, primary technique efficacy, local tumor progression (LTP), and secondary technique efficacy rates were analyzed and compared by the chi-square test or Fisher exact test. Prognostic factors for LTP and secondary technique efficacy were assessed using the Cox regression model. Major complications were also assessed.

RESULTS

With median follow-up of 15 months (range, 1-87 months), technical success and primary technique efficacy were 98.7% and 95.7% % in the non-surface contact group; 96.4% and 94.0% in the non-exophytic group; and 100% and 94.7% in the exophytic group (p > 0.05). Tumor size > 3 cm was a significant predictor for LTP, but not for secondary efficacy. Overall major complication rate was 3.8% (24/624) and was not different among the three groups.

CONCLUSION

Subcapsular HCCs can be effectively treated with thermal ablation techniques. Degree of tumor-surface contact including moderate protrusion does not appear to limit feasibility or procedure effectiveness.

KEY POINTS

• Subcapsular HCCs can be effectively treated with thermal therapy when proper image-guided technique and assistive techniques are applied. • Degree of tumor surface contact including moderate protrusion does not appear to limit feasibility or procedure effectiveness. • Major complications after percutaneous thermal ablation of subcapsular HCCs such as tumor seeding can be minimized by avoiding breach of the tumor capsule exposed to the peritoneal surface and use of tract ablation.

Hepatic Microwave Ablation in Challenging Locations

In recent years, there has been increased utilization of microwave ablation (MWA) in the treatment of soft tissue tumors. MWA has several theoretical advantages over radiofrequency ablation (RFA) by achieving a more rapid and sustained heating of tissues, increased efficacy in tissues with poor thermal conductivity, and less susceptibility to heat sink effect. While its greater power output has led to appropriate caution when applying this energy to soft tissue tumors, many commonly held beliefs regarding contraindications to MWA are unsupported by data and have been passed along based on experience with RFA. The goal of this article is to review the use of MWA in challenging clinical situations along with the existing evidence for its use.

Individualized Ablation of Hepatocellular Carcinoma: Tailored Approaches across the Phenotype Spectrum

Ablation is now recommended by international guidelines for the definitive treatment of hepatocellular carcinoma (HCC). Extensive clinical studies have demonstrated outcomes comparable to surgical resection with shorter hospital stays, decreased costs, and improved quality of life. Successful ablation requires complete treatment of both tumor and margin while preserving critical adjacent structures. HCC exhibits highly variable presentations in both anatomic involvement and biology which have significant implications on choice of ablative therapy. There are now abundant ablation modalities and adjunctive techniques which can be used to individualize ablation and maximize curative results. This article provides a patient-centered summary of approaches to HCC ablation in the context of patient performance, hepatic reserve, tumor phenotype and biology, intra- and extrahepatic anatomy, and ablation technology.

No-Touch Multi-bipolar Radiofrequency Ablation for the Treatment of Subcapsular Hepatocellular Carcinoma ≤ 5 cm Not Puncturable via the Non-tumorous Liver Parenchyma

PURPOSE

The percutaneous ablation of subcapsular hepatocellular carcinoma (S-HCC) may involve a risk of complications such as hemorrhage and tumor seeding, mainly linked to the direct tumor puncture often inevitable with mono-applicator ablation devices. The purpose of this study was to assess the efficacy and safety of no-touch multi-bipolar radiofrequency ablation (NTMBP-RFA) for the treatment of S-HCC ≤ 5 cm not puncturable via the non-tumorous liver parenchyma.

MATERIALS AND METHODS

Between September 2007 and December 2014, 58 consecutive patients (median age: 63 years [46-86], nine females) with 59 S-HCC ≤ 5 cm (median diameter: 25 mm [10-50 mm]), not puncturable via the non-tumorous liver parenchyma, were treated with NTMBP-RFA. Response and follow-up were assessed by CT or MRI. Complications were graded using the Cardiovascular and Interventional Radiological Society of Europe classification. Overall local tumor progression (OLTP)-free survival was assessed using the Kaplan-Meier method. A Cox proportional model evaluated the factors associated with OLTP. Signs of peritoneal or parietal tumor seeding were noted during follow-up imaging studies.

RESULTS

A complete ablation was achieved in 57/58 patients (98.3%) after one (n = 51) or two (n = 6) procedures. Three patients (5.2%) experienced complications (sepsis, cirrhosis decompensation; CIRSE grade 2 or 3). After a median follow-up period of 30.5 months [1-97], no patients had tumor seeding. The 1, 2 and 3-year OLTP-free survival rates were 98%, 94% and 91%, respectively. No factors were associated with OLTP.

CONCLUSION

NTMBP-RFA is a safe and effective treatment for S-HCC not puncturable via the non-tumorous liver parenchyma.

Comparison of microwave ablation and radiofrequency ablation for hepatocellular carcinoma: a systematic review and meta-analysis

BACKGROUND

Microwave ablation (MWA) has several advantages over radiofrequency ablation (RFA) for the treatment of hepatocellular carcinoma (HCC). We aimed to compare the efficacy and safety of MWA with those of RFA for HCC from the perspectives of percutaneous and laparoscopic approaches.

METHODS

PubMed/MEDLINE, Embase, the Cochrane library, and China Biology Medicine databases were searched. Studies comparing the efficacy and safety of MWA with those of RFA in patients with HCC were considered eligible. Complete ablation (CA), local recurrence (LR), disease-free survival (DFS), overall survival (OS), and the major complication rate were compared between MWA and RFA.

RESULTS

Four randomized controlled trials and 10 cohort studies were included. For percutaneous ablation, no significant difference was found between MWA and RFA regarding CA, LR, DFS, OS, and the major complication rate. A subgroup analysis of tumors measuring ≥3 cm revealed no difference in CA and LR for percutaneous ablation. For laparoscopic ablation, a significantly lower LR rate and a non-significant trend toward a higher major complication rate were observed for the MWA group (odds ratio [OR] 2.16, 95% confidence interval [CI] 1.16-4.02, p = .01 for LR; OR 0.21, 95% CI 0.04-1.03, p = .05 for major complication rate). CA, DFS, and OS were similar between the two groups.

CONCLUSIONS

Percutaneous (P)-MWA had similar therapeutic effects compared with P-RFA for HCC. Patients undergoing laparoscopic MWA had a lower LR rate; however, their major complication rate appeared to be higher. The superiority of MWA over RFA remains unclear and needs to be confirmed by high-quality evidence.

The local efficacy and influencing factors of ultrasound-guided percutaneous microwave ablation in colorectal liver metastases: a review of a 4-year experience at a single center

PURPOSE

To investigate the clinical effectiveness and safety of ultrasound (US)-guided percutaneous microwave ablation (MWA) for colorectal liver metastasis (CRLM) and evaluate the influencing factors of local efficacy.

METHODS

From January 2013 to January 2017, 137 CRLM patients accepting US-guided percutaneous MWA were included. The 2450-MHz microwave ablation system and a cooled-shaft antenna were used. All patients were regularly followed up for at least 6 months. Technical success, complete ablation, local tumor progression (LTP), complications and side effects were assessed. Logistic regression analysis was used to identify the independent prognostic factors for LTP.

RESULTS

In total, 411 lesions (mean diameter 15.4 ± 7.2 mm, range 5-67 mm) were treated. Complete ablation was achieved in 99.27% (408/411) of lesions and 97.81% (134/137) of patients. LTP occurred in 5.35% (22/411) of lesions and 16.06% (22/137) of patients. LTP was more likely to occur in lesions larger than 3 cm in diameter (OR: 14.71; p < .001; 95% CI: 3.7 3-57.92), near a large vascular structure (OR: 7.04; p < .001; 95% CI: 2.41-20.60), near the diaphragm (OR: 4.02; p = .049; 95% CI: 1.05-16.11) and in patients with no response to chemotherapy before MWA (OR: 3.25; p = .032; 95% CI: 1.14-15.30). MWA was well tolerated, with a major complication rate of 3.65%, a minor complication rate of 8.03% and a mortality rate of 0%. Fever and pain were the most common side effects after MWA.

CONCLUSIONS

US-guided percutaneous MWA of CRLM is a safe and effective method that is expected to become a routine treatment for local tumor control of CRLM.

Computed tomography-guided percutaneous microwave ablation of hepatocellular carcinoma in challenging locations: safety and efficacy of high-power microwave platforms

OBJECTIVE

To evaluate the clinical efficacy/safety of CT-guided percutaneous microwave ablation for HCC in challenging locations using high-power microwave platforms.

MATERIALS AND METHODS

A retrospective review was conducted in 26 patients with 36 HCC tumours in challenging locations (hepatic dome, subcapsular, close to the heart/diaphragm/hepatic hilum, exophytic) undergoing CT-guided percutaneous microwave ablation in a single centre since January 2011. Two different microwave platforms were used both operating at 2.45 GHz: AMICA and Acculis MWA System. Patient demographics including age, sex, tumour size and location, as well as technical details were recorded. Technical success, treatment response, patients survival and complication rate were evaluated.

RESULTS

Treated tumours were located in the hepatic dome (n = 14), subcapsularly (n = 16), in proximity to the heart (n = 2) or liver hilum (n = 2), while two were exophytic tumours at segment VI (n = 2). Mean tumour diameter was 3.30 cm (range 1.4-5 cm). In 3/26 patients (diameter >4 cm), an additional session of DEB-TACE was performed due to tumour size. Technical success rate was 100%; complete response rate was recorded in 33/36 tumours (91.6%). According to Kaplan-Meier analysis, survival rate was 92.3% and 72.11% at 24- and 60-month follow-up, respectively. There were no major complications; two cases of minor pneumothorax and two cases of small subcapsular haematoma were resolved only with observation requiring no further treatment.

CONCLUSION

CT-guided percutaneous microwave ablation for hepatocellular carcinoma tumours in challenging locations and up to 5 cm in diameter can be performed with high efficacy and safety rates.

When and how should we perform a biopsy for HCC in patients with liver cirrhosis in 2018? A review

The role of liver biopsy in the diagnosis of hepatocellular carcinoma (HCC) has changed over time. The diagnostic algorithm for this tumor is nowadays mainly based on radiological imaging, relegating histology to controversial cases, in which imaging techniques cannot establish a clear-cut diagnosis. This most commonly happens in small lesions, where biopsies frequently become mandatory, or in larger hypovascularized lesions. In this case however, the histological examination may not be reliable enough to grade the lesion, as different cell clones, deriving from sequential mutations, can originate heterogeneous cell populations. The risk of complications of liver biopsy, such as tumor seeding and intra-abdominal bleeding, needs to be reconsidered in light of new scientific evidence and of the technical improvements that have been introduced. Furthermore, increasing knowledge of the immunohistochemical and molecular characteristics of hepatocellular carcinoma opens a new scenario in which biopsy may play a decisive role in defining prognosis, and even treatment, by identifying the patient populations who could most benefit from target-driven hepatocellular carcinoma treatments, and therefore improving the success rate of experimental therapies. All the above reasons suggest that, overall, the role of liver biopsy in the management of HCC needs a reappraisal.

Percutaneous microwave ablation of exophytic tumours in hepatocellular carcinoma patients: Safe or not?

BACKGROUND & AIMS

To explore the long-term outcomes and safety of ultrasound-guided percutaneous microwave ablation (MWA) of exophytic tumours in hepatocellular carcinoma (HCC) patients.

METHODS

One hundred and thirty-two patients with subcapsular HCC were enrolled in this retrospective study. These patients were divided into the exophytic group (n=71) and non-exophytic group (n=61) according to the location of the tumour(s). A special technology of puncture and ablation was performed to treat the exophytic tumours. The local tumour progression (LTP), progression free survival (PFS) and overall survival (OS) were analysed using Kaplan-Meier and Log-rank tests.

RESULTS

Sixty-nine of 71 exophytic tumours and 60 of 61 subcapsular tumours were completely ablated. The complete ablation rates were 97.2% and 98.4% respectively. The follow-up periods ranged from 6 to 62 months with a median of 31 months in the exophytic group, and ranged from 5 to 61 months, with a median of 27 months in the non-exophytic group. The 1-, 3- and 5-year cumulative LTP rates were 2.4%, 12.3%, 18.4% and 5.1%, 12.0%, 17.8% in the exophytic and non-exophytic groups respectively (P=.733). The 1-, 3- and 5-year OS rates were 100%, 75.7%, 52.9% and 95.0%, 73.8%, 61.5% in the exophytic group and non-exophytic group respectively (P=.980). There was no procedure-related mortality or major complication.

CONCLUSION

Ultrasound-guided percutaneous MWA is safe and effective for exophytic tumours in HCC patients. Treated by MWA, the HCC patients with exophytic tumours can get the similar local response and long-term outcome to those with non-exophytic subcapsular tumours.

Efficacy and safety of ultrasound-guided percutaneous microwave ablation for the treatment of hepatic alveolar echinococcosis: A preliminary study

The present study aims to assess the efficacy and safety of ultrasound-guided percutaneous microwave ablation (MWA) for hepatic alveolar echinococcosis (HAE) preliminarily.Seventeen patients diagnosed to HAE and treated with MWA (80 watts, 4 min) were retrospectively analyzed. The upper abdominal computed tomography (CT) was performed at 1, 6, 12 months after the MWA treatment. The complications were evaluated to assess the safety.The diameters of the lesions in the HAE patients ranged from 1.9 to 4.7 cm. The patients included 10 males and 7 females, aged 26 to 70 (45.82 ± 13.36) years, 5 patients infecting with chronic hepatitis viral B and 8 patients with positive hydatid antibody (IgG). The lesions observed in the postoperative CT (1, 6, 12 months) were calcified compared with those observed in the preoperative CT and without relapse. No serious treatment-related complications occurred after treatment.MWA is a novel and effective therapeutic method for HAE with a single lesion (diameter≤=5 cm). Further studies based on prospective random control trials to confirm our findings are necessary.

Needle track seeding after radiofrequency ablation for hepatocellular carcinoma: prevalence, impact, and management challenge

Neoplastic seeding may arise after radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC). A low risk of seeding after RFA (0–1.1%) has been reported, which may rise up to 2.5% if ablation followed diagnostic biopsy. Needle track seeding presents with one or multiple rounded nodules along the needle track located within the peritoneum, along the abdominal muscles, which were penetrated by the needle, pleural surface, or in the subcutaneous and cutaneous tissues. The most widely used method for the assessment of seeding nodules is ultrasound (US), which usually displays hypoechoic nodules with intralesional vascularization. Fine needle aspiration biopsy of the nodule suspicious for malignant implant is mandatory to confirm the diagnosis and plan therapy. Wide surgical excision is the treatment of choice for neoplastic seeding. Thanks to early diagnosis and prompt treatment, development of needle track seeding is not likely to affect the long-term survival of patients.