Stereotactic radiofrequency ablation (SRFA) of liver lesions: technique effectiveness, safety, and interoperator performance

Surgery or Percutaneous Ablation for Liver Tumors? The Key Points Are: When, Where, and How Large

The most recent comparisons between liver resection (LR) and percutaneous thermal ablation (PTA) reported similar efficacy and survival outcomes for primary and secondary liver tumors ≤ 3 cm in size. Nevertheless, LR still remains the most popular treatment strategy worldwide, and percutaneous ablation is usually reserved to patients who are not surgical candidates. However, in our opinion, the debate should no longer be what is the most effective treatment for patients with resectable small liver cancer who are not candidates for liver transplantation, but rather when LR or PTA are best suited to the individual patient. Subcapsular tumors or tumors closely adjacent to critical structures or vulnerable organs should undergo LR because ablation can often not achieve an adequate safety margin. Conversely, PTA should be considered the first choice to treat central tumors because it has lower complication rates, lower costs, and shorter hospital stay. Furthermore, recent technical improvements in tumor targeting and accurate assessment of the extent of the safety margin, such as stereotactic navigation, fusion imaging and software powered by Artificial Intelligence enabling the immediate comparison between the pre-procedure planned margins and the ablation area, are also changing the approach to tumors larger than 3 cm. The next trials should be aimed at investigating up to what tumor size PTA supported by these advanced technologies can achieve outcomes comparable to LR.

Micro-robotic percutaneous targeting of type II endoleaks in the angio-suite

PURPOSE

Endovascular aneurysm repair has emerged as the standard therapy for abdominal aortic aneurysms. In 9-30% of cases, retrograde filling of the aneurysm sac through patent branch arteries may result in persistence of blood flow outside the graft and within the aneurysm sac. This condition is called an endoleak type II, which may be treated by catheter-based embolization in case of continued sac enlargement. If an endovascular access is not possible, percutaneous targeting of the perfused nidus remains the only option. However, this can be very challenging due to the difficult access and deep puncture with risk of organ perforation and bleeding. Innovative targeting techniques such as robotics may provide a promising option for safe and successful targeting.

METHODS

In nine consecutive patients, percutaneous embolization of type II endoleaks was performed using a table-mounted micro-robotic targeting platform. The needle path from the skin entry to the perfused nidus was planned based on the C-arm CT image data in the angio-suite. Entry point and path angle were aligned using the joystick-operated micro-robotic system under fluoroscopic control, and the coaxial needle was introduced until the target point within the perfused nidus was reached.

RESULTS

All punctures were successful, and there were no puncture-related complications. The pre-operative C-arm CT was executed in 11-15 s, and pathway planning required 2-3 min. The robotic setup and sterile draping were performed in 1-2 min, and the alignment to the surgical plan took no longer than 30 s.

CONCLUSION

Due to the small size, the micro-robotic platform seamlessly integrated into the routine clinical workflow in the angio-suite. It offered significant benefits to the planning and safe execution of double-angulated deeply localized targets, such as type II endoleaks.

Robotic Stereotactic Body Radiation Therapy for Oligometastatic Liver Metastases: A Systematic Review of the Literature and Evidence Quality Assessment

INTRODUCTION

The role of stereotactic body radiation therapy (SBRT) as a locally effective therapeutic approach for liver oligometastases from tumors of various origin is well established. We investigated the role of robotic SBRT (rSBRT) treatment on oligometastatic patients with liver lesions.

MATERIAL AND METHODS

This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The PubMed and Scopus databases were accessed by two independent investigators concerning robotic rSBRT for liver metastases, up to 3 October 2023.

RESULTS

In total, 15 studies, including 646 patients with 847 lesions that underwent rSBRT, were included in our systematic review. Complete response (CR) after rSBRT was achieved in 40.5% (95% CI, 36.66-44.46%), partial response (PR) in 19.01% (95% CI, 16.07-22.33%), whereas stable disease (SD) was recorded in 14.38% (95% CI, 11.8-17.41%) and progressive disease (PD) in 13.22% (95% CI, 10.74-16.17%) of patients. Progression-free survival (PFS) rates at 12 and 24 months were estimated at 61.49% (95% CI, 57.01-65.78%) and 32.55% (95% CI, 28.47-36.92%), respectively, while the overall survival (OS) rates at 12 and 24 months were estimated at 58.59% (95% CI, 53.67-63.33%) and 44.19% (95% CI, 39.38-49.12%), respectively. Grade 1 toxicity was reported in 13.81% (95% CI, 11.01-17.18%), Grade 2 toxicity in 5.57% (95% CI, 3.82-8.01%), and Grade 3 toxicity in 2.27% (955 CI, 1.22-4.07%) of included patients.

CONCLUSIONS

rSBRT represents a promising method achieving local control with minimal toxicity in a significant proportion of patients. Further studies are needed to evaluate the role of rSBRT in the management of metastatic liver lesions.

Hepatocellular carcinoma

An update on the management of Hepatocellular carcinoma (HCC) is provided in the present article for those interested in the UEMS/EBSQ exam in Surgical Oncology. The most recent publications in HCC, including surveillance, guidelines, and indications for liver resection, liver transplantation, and locoregional or systemic therapies, are summarised. The objective is to yield a set of main points regarding HCC that are required in the core curriculum of hepatobiliary oncological surgery.

Stereotactic ablation: A game changer?

For both primary and metastatic liver cancer, thermal ablation represents an interesting alternative to surgery. However, except for a small fraction of patients, conventional ultrasound- and CT-guided single-probe approaches have not achieved oncologic outcomes comparable with surgery. In this overview, we describe our stereotactic ablation workflow and discuss the short- and long-term results of stereotactic radiofrequency ablation (SRFA) and stereotactic microwave ablation (SMWA) for the treatment of primary and secondary liver tumours. The advantages of this method are discussed together with a summary of the existing stereotactic techniques for thermal ablation and the clinical data that support them. Stereotactic ablation is based on an optical navigation system and a specialized aiming tool. The workflow includes advanced three-dimensional planning, precise needle/probe placements according to the plan and intraoperative image fusion to check the needle positions and the ablation margins. Stereotactic ablation offers all the advantages of a minimally invasive procedure while producing oncological results comparable with surgery. The number of locally treatable liver cancers may be significantly expanded with these cutting-edge instruments and methods. We firmly believe that it can become a cornerstone in the treatment of liver cancers.

Unresectable Intermediate-Size (3-5 cm) Colorectal Liver Metastases: Stereotactic Ablative Body Radiotherapy Versus Microwave Ablation (COLLISION-XL): Protocol of a Phase II/III Multicentre Randomized Controlled Trial

BACKGROUND

Although microwave ablation (MWA) has a low complication rate and good efficacy for small-size (≤ 3 cm) colorectal liver metastases (CRLM), local control decreases with increasing size. Stereotactic body radiotherapy (SBRT) is gaining interest as a potential means to treat intermediate-size CRLM and might be less susceptible to increasing volume. The objective of this study is to compare the efficacy of MWA to SBRT in patients with unresectable, intermediate-size (3-5 cm) CRLM.

METHODS

In this two-arm, multicentre phase II/ III randomized controlled trial, 68 patients with 1-3 unresectable, intermediate-size CRLM suitable for both MWA and SBRT, will be included. Patients will be treated with MWA or SBRT as randomised. The Primary endpoint is local tumour progression-free survival (LTPFS) at 1 year (intention-to-treat analysis). Main secondary endpoints are overall survival, overall and distant progression-free survival (DPFS), local control (LC) and procedural morbidity and mortality and assessment of pain and quality of life.

DISCUSSION

Current guidelines lack clear recommendations for the local treatment of liver only intermediate-size, unresectable CRLM and studies comparing curative intent SBRT and thermal ablation are scarce. Although safety and feasibility to eradicate tumours ≤ 5 cm have been established, both techniques suffer from lower LTPFS and LC rates for larger-size tumours. For the treatment of unresectable intermediate-size CRLM clinical equipoise has been reached. We have designed a two-armed phase II/ III randomized controlled trial directly comparing SBRT to MWA for unresectable CRLM 3-5 cm.

LEVEL OF EVIDENCE

Level 1, phase II/ III Randomized controlled trial.

TRIAL REGISTRATION

NCT04081168, September 9th 2019.

Lipid Nanoparticles-Based Therapy in Liver Metastasis Management: From Tumor Cell-Directed Strategy to Liver Microenvironment-Directed Strategy

Metastasis to the liver, as one of the most frequent metastatic patterns, was associated with poor prognosis. Major drawbacks of conventional therapies in liver metastasis were the lack of metastatic-targeting ability, predominant systemic toxicities and incapability of tumor microenvironment modulations. Lipid nanoparticles-based strategies like galactosylated, lyso-thermosensitive or active-targeting chemotherapeutics liposomes have been explored in liver metastasis management. This review aimed to summarize the state-of-art lipid nanoparticles-based therapies in liver metastasis management. Clinical and translational studies on the lipid nanoparticles in treating liver metastasis were searched up to April, 2023 from online databases. This review focused not only on the updates in drug-encapsulated lipid nanoparticles directly targeting metastatic cancer cells in treating liver metastasis, but more importantly on research frontiers in drug-loading lipid nanoparticles targeting nonparenchymal liver tumor microenvironment components in treating liver metastasis, which showed promise for future clinical oncological practice.

Ablative Therapy in Non-HCC Liver Malignancy

Surgical extirpation of liver tumors remains a proven approach in the management of metastatic tumors to the liver, particularly those of colorectal origin. Ablative, non-resective therapies are an increasingly attractive primary therapy for liver tumors as they are generally better tolerated and result in far less morbidity and mortality. Ablative therapies preserve greater normal liver parenchyma allowing better post-treatment liver function and are particularly appropriate for treating subsequent liver-specific tumor recurrence. This article reviews the current status of ablative therapies for non-hepatocellular liver tumors with a discussion of many of the clinically available approaches.

Reliability of Stereotactic Radiofrequency Ablation (SRFA) for Malignant Liver Tumors: Novice versus Experienced Operators

PURPOSE

To compare the results of a novice with those of experienced interventional radiologists (IRs) for stereotactic radiofrequency ablation (SRFA) of malignant liver tumors in terms of safety, technical success, and local tumor control.

METHODS

A database, including all SRFA procedures performed in a single center between January 2011 and December 2018 was retrospectively analyzed. A total of 39 ablation sessions performed by a novice IR were compared to the results of three more experienced IRs. Comparative SRFA sessions were selected using propensity score matching considering tumor type, age, sex, tumor size, and tumor number as matching variables. Overall, 549 target tumors were treated in 273 sessions. Median tumor size was 2.2 cm (1.0-8.5 cm) for 178 hepatocellular carcinomas (HCCs) and 3.0 cm (0.5-13.0 cm) for 371 metastases. A median of 2 (1-11) tumors were treated per session.

RESULTS

No significant differences were observed when comparing the results of more experienced IRs with those of a novice IR regarding the rates of major complications (6.8% [16/234] vs. 5.1% [2/39]; p = 0.477), mortality (1.3% [2/234] vs. 0% [0/39]; p = 0.690), primary technical efficacy (98.5% [525/533] vs. 98.9% [94/95]; p = 0.735), and local recurrence (5.6% [30/533] vs. 5.3% [5/95]; p = 0.886). However, the median planning/placement time was significantly shorter for the experienced IRs (92 min vs. 119 min; p = 0.002).

CONCLUSIONS

SRFA is a safe, effective, and reliable treatment option for malignant liver tumors and favorable outcomes can be achieved even by inexperienced operators with minimal supervision.

Identification and characterization of patients being exposed to computed-tomography associated radiation-doses above 100 mSv in a real-life setting

Rationale and objectives

Patients receiving high cumulative effective doses (CED) from recurrent computed tomography (CT) in a real-life setting are not well identified. Evaluation of causes and patient characteristics may help to define individuals potentially at risk of radiation-induced secondary malignancies.

Materials and methods

Patients who received a CED > 100 mSv from CT scans during October 2012 and April 2020 at a tertiary university center were identified with the help of a radiological radiation dose monitoring system. The primary disease and referral diagnosis, number of CT exams, time period, age, BMI and gender distribution of the 1000 patients with the highest CED were analysed.

Results

3431 patients had a CED of more than 100 mSv, which corresponded to 2.75% of all patients who received a CT exam. From the 1000 patients with the highest CED, mean number of CT exams per patient was 14.6, mean CED was 257 mSv (SD 98, range 177-1339). Mean age of patients was 63.9 years (SD 10.6), male to female ratio 3:2, and mean BMI 28.7 kg/m2 (SD 5.5). 728 (72.9%) patients had cancer. The leading primary diagnosis was liver cirrhosis in 197 patients and 103 patients had a liver transplantation. In patients with liver cirrhosis, 750 exams were indicated for the follow-up of the disease, 662 for the clarification of an acute clinical condition, and 202 for CT-guided stereotactic radiofrequency ablation.

Conclusion

Recurrent CT scans of patients with cancer, liver cirrhosis and liver transplantation may lead to critically high CED.

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.

Stereotactic and Robotic Minimally Invasive Thermal Ablation of Malignant Liver Tumors: A Systematic Review and Meta-Analysis

Background

Stereotactic navigation techniques aim to enhance treatment precision and safety in minimally invasive thermal ablation of liver tumors. We qualitatively reviewed and quantitatively summarized the available literature on procedural and clinical outcomes after stereotactic navigated ablation of malignant liver tumors.

Methods

A systematic literature search was performed on procedural and clinical outcomes when using stereotactic or robotic navigation for laparoscopic or percutaneous thermal ablation. The online databases Medline, Embase, and Cochrane Library were searched. Endpoints included targeting accuracy, procedural efficiency, and treatment efficacy outcomes. Meta-analysis including subgroup analyses was performed.

Results

Thirty-four studies (two randomized controlled trials, three prospective cohort studies, 29 case series) were qualitatively analyzed, and 22 studies were included for meta-analysis. Weighted average lateral targeting error was 3.7 mm (CI 3.2, 4.2), with all four comparative studies showing enhanced targeting accuracy compared to free-hand targeting. Weighted average overall complications, major complications, and mortality were 11.4% (6.7, 16.1), 3.4% (2.1, 5.1), and 0.8% (0.5, 1.3). Pooled estimates of primary technique efficacy were 94% (89, 97) if assessed at 1–6 weeks and 90% (87, 93) if assessed at 6–12 weeks post ablation, with remaining between-study heterogeneity. Primary technique efficacy was significantly enhanced in stereotactic vs. free-hand targeting, with odds ratio (OR) of 1.9 (1.2, 3.2) (n = 6 studies).

Conclusions

Advances in stereotactic navigation technologies allow highly precise and safe tumor targeting, leading to enhanced primary treatment efficacy. The use of varying definitions and terminology of safety and efficacy limits comparability among studies, highlighting the crucial need for further standardization of follow-up definitions.

Recurrence and survival following microwave, radiofrequency ablation, and hepatic resection of colorectal liver metastases: A systematic review and network meta-analysis

BACKGROUND

Gold standard for colorectal liver metastases (CRLM) remains hepatic resection (HR). However, patients with severe comorbidities, unresectable or deep-situated resectable CRLM are candidates for ablation. The aim of the study was to compare recurrence rate and survival benefit of the microwave ablation (MWA), radiofrequency ablation (RFA) and HR by conducting the first network meta-analysis.

DATA SOURCES

Systematic search of the literature was conducted in the electronic databases. Both updated traditional and network meta-analyses were conducted and the results were compared between them.

RESULTS

HR cohort demonstrated significantly less local recurrence rate and better 3- and 5-year disease-free (DFS) and overall survival (OS) compared to MWA and RFA cohorts. HR cohort included significantly younger patients and with significantly lower preoperative carcinoembryonic antigen (CEA) by 10.28 ng/mL compared to RFA cohort. Subgroup analysis of local recurrence and OS of solitary and ≤ 3 cm CRLMs did not demonstrate any discrepancies when compared with the whole sample.

CONCLUSIONS

For resectable CRLM the treatment of choice still remains HR. MWA and RFA can be used as a single or adjunct treatment in patients with unresectable CRLM and/or prohibitive comorbidities.

Update on the association of hepatitis B with intrahepatic cholangiocarcinoma: Is there new evidence?

Intrahepatic cholangiocarcinoma (iCCA) is a subgroup of cholangiocarcinoma that accounts for about 10%-20% of the total cases. Infection with hepatitis B virus (HBV) is one of the most important predisposing factors leading to the formation of iCCA. It has been recently estimated based on abundant epidemiological data that the association between HBV infection and iCCA is strong with an odds ratio of about 4.5. The HBV-associated mechanisms that lead to iCCA are under intense investigation. The diagnosis of iCCA in the context of chronic liver disease is challenging and often requires histological confirmation to distinguish from hepatocellular carcinoma. It is currently unclear whether antiviral treatment for HBV can decrease the incidence of iCCA. In terms of management, surgical resection remains the mainstay of treatment. There is a need for effective treatment modalities beyond resection in both first- and second-line treatment. In this review, we summarize the epidemiological evidence that links the two entities, discuss the pathogenesis of HBV-associated iCCA, and present the available data on the diagnosis and management of this cancer.

Stereotactic Thermal Ablation of Liver Tumors: 3D Planning, Multiple Needle Approach, and Intraprocedural Image Fusion Are the Key to Success-A Narrative Review

Thermal ablation is an emerging, potentially curative approach in treating primary and metastatic liver cancer. Different technologies are available, with radiofrequency ablation (RFA) and microwave ablation (MWA) being the most widely used. Regardless of the technique, destruction of the entire tumor, including an adequate safety margin, is key. In conventional single-probe US- or CT-guided thermal ablation, the creation of such large necrosis zones is often hampered by technical limitations, especially for large tumors (i.e., >2-3 cm). These limitations have been overcome by stereotactic RFA (SRFA): a multiple needle approach with 3D treatment planning and precise stereotactic needle placement combined with intraprocedural image fusion of pre- and post-interventional CT scans for verification of treatment success. With these sophisticated tools and advanced techniques, the spectrum of locally curable liver malignancies can be dramatically increased. Thus, we strongly believe that stereotactic thermal ablation can become a cornerstone in the treatment of liver malignancies, as it offers all the benefits of a minimally invasive method while providing oncological outcomes comparable to surgery. This article provides an overview of current stereotactic techniques for thermal ablation, summarizes the available clinical evidence for this approach, and discusses its advantages.

Stereotactic radiofrequency ablation of a variety of liver masses in children

BACKGROUND AND AIMS

Surgical resection is currently the cornerstone of liver tumor treatment in children. In adults radiofrequency ablation (RFA) is an established minimally invasive treatment option for small focal liver tumors. Multiprobe stereotactic RFA (SRFA) with intraoperative image fusion to confirm ablation margins allows treatment for large lesions. We describe our experience with SRFA in children with liver masses.

METHODS

SRFA was performed in 10 patients with a median age of 14 years (range 0.5-17.0 years) suffering from liver adenoma (n = 3), hepatocellular carcinoma (n = 1), hepatoblastoma (n = 2), myofibroblastic tumor (n = 1), hepatic metastases of extrahepatic tumors (n = 2) and infiltrative hepatic cysts associated with alveolar echinococcosis (n = 1). Overall, 15 lesions with a mean lesion size of 2.6 cm (range 0.7-9.5 cm) were treated in 11 sessions.

RESULTS

The technical success rate was 100%, as was the survival rate. No transient adverse effects higher than grade II (Clavien and Dindo) were encountered after interventions. The median hospital stay was 5 d (range 2-33 d). In two patients who subsequently underwent transplant hepatectomy complete ablation was histologically confirmed. Follow-up imaging studies (median 55 months, range 18-129 months) revealed no local or distant recurrence of disease in any patient.

CONCLUSIONS

SRFA is an effective minimal-invasive treatment option in pediatric patients with liver tumors of different etiologies.

Software-based planning of ultrasound and CT-guided percutaneous radiofrequency ablation in hepatic tumors

Objectives

Radiofrequency ablation (RFA) can be associated with local recurrences in the treatment of liver tumors. Data obtained at our center for an earlier multinational multicenter trial regarding an in-house developed simulation software were re-evaluated in order to analyze whether the software was able to predict local recurrences.

Methods

Twenty-seven RFA ablations for either primary or secondary hepatic tumors were included. Colorectal liver metastases were shown in 14 patients and hepatocellular carcinoma in 13 patients. Overlap of the simulated volume and the tumor volume was automatically generated and defined as positive predictive value (PPV) and additionally visually assessed. Local recurrence during follow-up was defined as gold standard. Sensitivity and specificity were calculated using the visual assessment and gold standard.

Results

Mean tumor size was 18 mm (95% CI 15–21 mm). Local recurrence occurred in 5 patients. The PPV of the simulation showed a mean of 0.89 (0.84–0.93 95% CI). After visual assessment, 9 incomplete ablations were observed, of which 4 true positives and 5 false positives for the detection of an incomplete ablation. The sensitivity and specificity were, respectively, 80% and 77% with a correct prediction in 78% of cases. No significant correlation was found between size of the tumor and PPV (Pearson Correlation 0.10; p = 0.62) or between PPV and recurrence rates (Pearson Correlation 0.28; p = 0.16).

Conclusions

The simulation software shows promise in estimating the completeness of liver RFA treatment and predicting local recurrence rates, but could not be performed real-time. Future improvements in the field of registration could improve results and provide a possibility for real-time implementation.

Thermal ablation of CT 'invisible' liver tumors using MRI fusion: a case control study

Purpose: To evaluate whether 'invisible' liver tumors on CT can be treated by stereotactic radiofrequency ablation (SRFA) using fusion of pre-ablation MRI.Methods: In this retrospective case-control study, 60 patients (14 with Hepatocellular carcinoma (HCC) and 46 with metastatic liver tumors) with CT 'invisible' lesions underwent SRFA using MRI-fusion between June 2005 and June 2018 ('fusion group'). For comparison, 60 patients who underwent SRFA without image fusion were selected using nearest neighbor propensity score matching ('control group'). Endpoints consisted of local tumor control, safety, overall and disease-free survival.Results: Major complications occurred in 6/69 ablations (8.7%) in the fusion group and in 6/89 ablations (6.7%) in the control group (p = 0.434). Primary technical efficacy rate (i.e., successful initial ablation) was 96.6% (28/29) for HCC and 97.9% (166/170) for metastatic disease in the fusion group and 100% (33/33) and 93.3% (184/194) in the control group, respectively (p = 0.468 and 0.064). Local recurrence (LR) was observed in 1/29 (3.5%) HCCs and in 6/170 metastases (4.0%) in the fusion group and 1/33 (3.0%) and 21/196 (10.7%) in the control group, respectively. The LR rate of metastasis in the control group was significantly higher (p = 0.007), although differences in OS and DFS did not reach statistical significance.Conclusions: Image fusion using pre-procedural MRI allows for ablation of CT-'invisible' liver tumors that are otherwise untreatable. Moreover, local oncological control was higher in metastatic liver tumors versus matched controls which suggests it could be useful tool for all stereotactic radiofrequency ablation procedures.

Stereotactic Image-Guided Microwave Ablation for Malignant Liver Tumors-A Multivariable Accuracy and Efficacy Analysis

Background: Therapeutic success of thermal ablation for liver tumors depends on precise placement of ablation probes and complete tumor destruction with a safety margin. We investigated factors influencing targeting accuracy and treatment efficacy of percutaneous stereotactic image-guided microwave ablation (SMWA) for malignant liver neoplasms. Materials and methods: All consecutive patients treated with SMWA for malignant liver tumors over a 3-year period were analyzed. A computed tomography-based navigation system was used for ablation probe trajectory planning, stereotactic probe positioning, and validation of probe positions and ablation zones. Factors potentially influencing targeting accuracy [target positioning error (TPE)] and treatment efficacy within 6 months [ablation site recurrence (ASR)] were analyzed in a multivariable regression model, including challenging lesion locations (liver segments I, VII, and VIII; subphrenic location). Results: Three hundred one lesions (174 hepatocellular carcinomas, 87 colorectal liver metastases, 17 neuroendocrine tumors, and 23 others) were targeted in 191 interventions in 153 patients. The median TPE per ablation probe was 2.9 ± 2.3 mm (n = 384). Correction of ablation probe positions by repositioning was necessary in 4 out of 301 lesions (1%). Factors significantly influencing targeting accuracy were cirrhosis (R 0.67, CI 0.22-1.12) and targeting trajectory length (R 0.21, CI 0.12-0.29). Factors significantly influencing early ASR were lesion size >30 mm (OR 5.22, CI 2.44-11.19) and TPE >5 mm (OR 2.48, CI 1.06-5.78). Challenging lesion locations had no significant influence on targeting accuracy or early ASR. Conclusions: SMWA allows precise and effective treatment of malignant liver tumors even for lesions in challenging locations, with treatment efficacy depending on targeting accuracy in our model. Allowing for many tumors to be safely reached, SMWA has the potential to broaden treatment eligibility for patients with otherwise difficult to target tumors.

Simultaneous Stereotactic Radiofrequency Ablation of Multiple (≥ 4) Liver Tumors: Feasibility, Safety, and Efficacy

PURPOSE

To assess feasibility, safety, and clinical outcome of simultaneous stereotactic radiofrequency (RF) ablation of multiple (≥ 4) primary and metastatic liver tumors.

MATERIALS AND METHODS

This retrospective observational study included 92 patients (29 women, 62 men), 35 with ≥ 4 hepatocellular carcinomas (HCCs) and 57 with ≥ 4 metastatic liver tumors at initial stereotactic RF ablation between 2005 and 2018. The median size of 178 HCCs and 371 metastases was 2.2 cm (range, 1.0-8.5 cm) and 3.0 cm (range, 0.5-13 cm), respectively. At initial stereotactic RF ablation, 17 (48.6%) patients with HCC and 19 (33.3%) with metastases had 4 liver tumors, 11 (31.4%) and 19 (33.3%) had 5 tumors, and 7 (20%) and 19 (33.3%) had ≥ 6 tumors.

RESULTS

Major complications occurred in 2 of 35 ablations (5.4%) in patients with HCCs and in 7 of 63 (10%) with metastases. The primary technical efficacy rate (ie, successful initial ablation) was 100% (178/178) in HCCs and 98.8% (363/371) in metastases. Local recurrence was observed in 4 of 178 (2.2%) HCCs and in 17 of 371 (4.6%) metastases. Overall survival (OS) rates at 1, 3, and 5 years from the date of the first stereotactic RF ablation were 88.0%, 54.0%, and 30.4% for patients with HCCs with a median OS of 38.2 months and 86.1%, 53.1%, and 37.3% for patients with metastases with a median OS of 37.4 months.

CONCLUSIONS

Stereotactic RF ablation is a feasible, safe, and efficacious option in simultaneous management of multiple primary and metastatic liver tumors.

Stereotactic radiofrequency ablation of subcardiac hepatocellular carcinoma: a case-control study

Purpose: The purpose of this study is to evaluate the safety and efficacy of stereotactic radiofrequency ablation (SRFA) for the treatment of subcardiac hepatocellular carcinoma (HCC). Material and methods: From 2003 to 2018, 79 consecutive patients underwent 104 multi-probe SRFA sessions for the treatment of 114 subcardiac HCC with a median size of 2.5 cm (0.5-9.5 cm). The results were compared with a randomly selected control group of 79 patients with 242 HCC with a median size of 2.0 cm (0.5-12 cm) following SRFA in other (non-subcardiac) locations with propensity score matching. Results: The 95.6% of the tumors were successfully treated by the first ablation session (primary technical efficacy rate) and 99.1% after the second session (secondary technical efficacy rate). Local tumor recurrence developed in 8 nodules (7.0%). Major complication and perioperative mortality rates were 7.7% (8/104) and 1% (1/104), respectively. The overall survival (OS) rates from the date of the first SRFA with single subcardiac HCCs were 92%, 77% and 65% at 1, 3 and 5 years, respectively, with a median OS of 90.6 months. The disease-free survival (DFS) after SRFA was 75, 34 and 34%, at 1, 3 and 5 years, respectively, with a median DFS of 19.1 months. There was no statistically significant difference with the control group in terms of local tumor control, safety, OS and DFS. Conclusion: SRFA of subcardiac tumors is as safe and efficacious as when treating tumors remote from the heart.

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.

Stereotactic Radiofrequency Ablation of Liver Tumors in Octogenarians

Purpose: This study aimed to evaluate the efficacy and overall clinical outcome of patients over the age of 80 undergoing stereotactic radiofrequency ablation (SRFA) and to compare the results to a younger population with propensity score matching.

Materials and Methods: Between 2006 and 2018 36 patients aged between 80 and 90 years underwent 46 SRFA sessions of 70 primary and secondary liver tumors. For comparison of treatment safety and efficacy 36 younger patients were selected with propensity score matching by the R package “MatchIt” in this retrospective, single-center study.

Results: 68/70 tumors were successfully ablated at first ablation session (97% primary technical efficacy rate). Local tumor recurrence developed in 5 of 70 nodules (7.1%). The complication rate above Clavien-Dindo Grade III was 6.5% (3 of 46). The overall survival (OS) rates at 1-, 3-, and 5- years from the date of the first SRFA were 84.6, 50.5, and 37.9% for HCC patients and 87.5%, 52.5% at 1-, and 3-years for CRC patients. The disease-free survival (DFS) for HCC patients after SRFA was 79.1, 35.6, and 23.7%, at 1-, 3-, and 5- years, and 75%, 22.5% at 1-, and 3-years for CRC patients. There were no significant differences in terms of technical efficacy, local recurrences, major complications, OS and DFS compared to the control group.

Conclusion: SRFA in octogenarians is a safe, feasible and useful option in the management of primary or metastatic liver tumors with no significant difference in outcomes compared to a younger control group.

Local Treatment of Breast Cancer Liver Metastasis

Breast cancer represents a leading cause of death worldwide. Despite the advances in systemic therapies, the prognosis for patients with breast cancer liver metastasis (BCLM) remains poor. Especially in case of failure or cessation of systemic treatments, surgical resection for BCLMs has been considered as the treatment standard despite a lack of robust evidence of benefit. However, due to the extent and location of disease and physical condition, the number of patients with BCLM who are eligible for surgery is limited. Palliative locoregional treatments of liver metastases (LM) include transarterial embolization (TAE), transarterial chemoembolization (TACE), and selective internal radiotherapy (SIRT). Percutaneous thermal ablation methods, such as radiofrequency ablation (RFA) and microwave ablation (MWA), are considered potentially curative local treatment options. They are less invasive, less expensive and have fewer contraindications and complication rates than surgery. Because conventional ultrasound- and computed tomography-guided single-probe thermal ablation is limited by tumor size, multi-probe stereotactic radiofrequency ablation (SRFA) with intraoperative image fusion for immediate, reliable judgment has been developed in order to treat large and multiple tumors within one session. This review focuses on the different minimally invasive local and locoregional treatment options for BCLM and attempts to describe their current and future role in the multidisciplinary treatment setting.

Stereotactic Radiofrequency Ablation of Hepatocellular Carcinoma: a Histopathological Study in Explanted Livers

This retrospective study was performed to evaluate the efficacy of three-dimensional (3D)-navigated multiprobe radiofrequency ablation (RFA) with intraprocedural image fusion for treatment of hepatocellular carcinoma (HCC) by histopathological examination. From 2009 to 2018, 97 patients (84 men, 13 women; median age, 60 years; range, 1-71) were transplanted after bridging therapy of 195 HCCs by stereotactic RFA (SRFA). The median interval between the first SRFA and transplantation was 6.8 months (range, 0-71). The rate of residual vital tissue (RVT) could be assessed in 188 of 195 lesions in 96 of 97 patients by histological examination of the explanted livers using hematoxylin and eosin (H&E) and Tdt-mediated UTP nick-end labeling (TUNEL) stains. Histopathological results were compared with the findings of the last computed tomography (CT) imaging before liver transplantation (LT). Median number and size of treated tumors were 1 (range, 1-8) and 2.5 cm (range, 1-8). Complete radiological response was achieved in 186 of 188 nodules (98.9%) and 94 of 96 patients (97.9%) and complete pathological response in the explanted liver specimen in 183 of 188 nodules (97.3%) and 91 of 96 patients (94.8%), respectively. In lesions ≥3 cm, complete tumor cell death was achieved in 50 of 52 nodules (96.2%). Residual tumor did not correlate with tumor size (P = 0.5). Conclusion: Multiprobe SRFA with intraprocedural image fusion represents an efficient, minimally invasive therapy for HCC, even with tumor sizes larger than 3 cm, and without the need of a combination with additional treatments. The results seem to justify the additional efforts related to the stereotactic approach.

Combined ultrasound/computed tomography guidance in percutaneous radiofrequency ablation after transarterial chemoembolization for hepatocellular carcinoma in the hepatic dome

Purpose

To assess the value of the combined ultrasound (US)/computed tomography (CT) guidance (US guidance was firstly used for puncture with the electrode needle to the site close to the tumor, and subsequently, CT guidance was used for precise positioning of the electrode tips) in percutaneous radiofrequency ablation (RFA) after transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) in the hepatic dome.

Methods

From January 1, 2013 to June 30, 2017, medical records of 65 patients with HCCs in the hepatic dome who received TACE treatment before RFA procedure were retrospectively analyzed. Among them, 34 patients with 35 liver tumors underwent percutaneous RFA under combined US/CT guidance, and 31 patients with 35 liver tumors received percutaneous RFA under CT guidance alone. The efficacy of combined US/CT-guided RFA was analyzed, and the procedure time and safety between the two groups were compared.

Results

In the combined US/CT-guided RFA group, the 1-, 3-, and 5-year local recurrence rates were 3%, 6%, 9%, respectively, and the 1-, 3-, and 5-year overall survival rates were 100%, 97%, 94%, respectively. The mean procedure time in the CT-guided RFA group was significantly longer than that of the combined US/CT-guided RFA group (P<0.001). Although the overall complication rates between the two groups were not statistically significant, there were no occurrences of RFA-related complications in the combined US/CT-guided RFA group. The incidence of postoperative adverse reaction of right upper quadrant pain in the CT-guided RFA group was greater than that of the combined US/CT-guided RFA group (P=0.01).

Conclusion

Percutaneous RFA under the combined US/CT guidance was helpful for HCC in the hepatic dome.

Systemic Hypotension Following Intravenous Administration of Nonionic Contrast Medium During Computed Tomography: Iopromide Versus Iodixanol

BACKGROUND

In light of the increasing number of radiologic interventions performed under general anesthesia, the effects of contrast media (CM) on circulation and organ perfusion are of paramount importance. The objectives of this study were to systematically quantify effects on blood pressure, heart rate, and kidney function following intravenous administration of nonionic CM with normal and low osmolality.

METHODS

In this controlled, double-blinded phase IV clinical trial, 40 consecutive patients were randomly assigned to receive repeated measures of either low-osmolar iopromide or iso-osmolar iodixanol. Normal saline solution (NSS) served as control. Blood pressure and heart rate were measured continuously from 1 minute before until 3 minutes after administration of CM and NSS. Urine output was recorded hourly.

RESULTS

Administration of iopromide resulted in systemic hypotension lasting up to 300 seconds (105 ± 61 seconds) with the lowest mean arterial pressure of 39 mm Hg (56.7 ± 12.2 mm Hg). Iopromide caused a systolic/diastolic decrease of 31/26 mm Hg (P < .001), significant increase in heart rate (P = .042), and significant diuresis with a 2-fold higher per-hour urine output (P = .010). Administration of iodixanol and NSS had no significant influence on blood pressure (P > .640).

CONCLUSIONS

Administration of low-osmolar iopromide was followed by a significant transient decrease in blood pressure and a rise in heart rate. Anesthetists and radiologists should be aware of these effects in patients in whom short episodes of disturbed tissue microcirculation may pose a clinical risk.

Multi-Operational Selective Computer-Assisted Targeting of hepatocellular carcinoma-Evaluation of a novel approach for navigated tumor ablation

Objective

To facilitate precise local ablation of hepatocellular carcinoma (HCC) in a setting of combined ablation and transarterial chemoembolization (TACE), we evaluated accuracy and efficiency of a novel technique for navigated positioning of ablation probes using intrahepatic tumor referencing and electromagnetic (EM) guidance, in a porcine model.

Methods

An angiographic wire with integrated EM reference sensor at its tip was inserted via a transarterial femoral access and positioned in the vicinity of artificial liver tumors. The resulting offset distance between the tumor center and the intrahepatic endovascular EM reference was calculated. Subsequently, EM tracked ablation probes were inserted percutaneously and navigated toward the tumor center, relying on continuous EM guidance via the intrahepatic reference. Targeting accuracy was assessed as the Euclidean distance between the tip of the ablation probe and the tumor center (Target Positioning Error, TPE). Procedural efficiency was assessed as time efforts for tumor referencing and tumor targeting.

Results

In 6 animals, 124 targeting measurements were performed with an offset distance < 30 mm (clinically most feasible position), resulting in a mean TPE of 2.9 ± 1.6 mm. No significant correlation between the TPE and different intrahepatic offset distances (range 21 to 61 mm, n = 365) was shown as long as the EM reference was placed within the liver. However, the mean TPE increased when placing the EM reference externally on the animal skin (p < 0.01). TPE was similar when targeting under continuous ventilation or in apnea (p = 0.50). Mean time for tumor referencing and navigated targeting was 6.5 ± 3.8 minutes and 14 ± 8 seconds, respectively.

Conclusion

The proposed technique allows precise and efficient navigated positioning of ablation probes into liver tumors in the animal model. We introduce a simple approach suitable for combined ablation and TACE of HCC in a single treatment session.

Stereotactically navigated percutaneous microwave ablation (MWA) compared to conventional MWA: a matched pair analysis

PURPOSE

To compare CT-navigated stereotactic microwave ablation (SMWA) to non-navigated conventional MWA (CMWA) for percutaneous ablation of liver malignancies.

METHODS

A matched pair analysis of 36 patients who underwent MWA of primary or secondary liver malignancies (10 hepatocellular carcinoma and 8 metastases) was conducted. A total of 18 patients undergoing SMWA were included in this prospective study. Patients were matched in terms of tumor size, liver segment and entity to retrospective CMWA procedures. The endpoints were procedure time, accuracy of needle placement, technical success rate, complication rate and dose-length product (DLP).

RESULTS

The procedure durations were 23.9 min (SD 3.7) for CMWA and 21.8 min (SD 16.3) for SMWA (p = 0.22). The procedural accuracy for SMWA and CMWA was identical for both groups (3.7 mm). The total DLP was significantly lower for SMWA than for CMWA (2115 mGy cm (SD 276) vs. 3109 mGy cm (SD 1137), respectively; p < 0.01). Complete ablation without residual tumor was observed in 94% (17 of 18) of SMWA and in 83% (15 of 18) of CMWA patients (p = 0.31). No complications occurred.

CONCLUSIONS

SMWA is highly accurate and reduces the radiation dose without increasing the procedure time.

Stereotactic Radiofrequency Ablation for Breast Cancer Liver Metastases

PURPOSE

To evaluate outcomes in patients with liver metastases from breast cancer treated with stereotactic radiofrequency (RF) ablation.

MATERIALS AND METHODS

A retrospective analysis of 29 stereotactic RF ablation treatment sessions in 26 consecutive patients with 64 biopsy-proven breast cancer liver metastases (BCLMs) was conducted. Patients were included only if systemic treatment failed and all visible BCLMs were treatable.

RESULTS

Primary and secondary technical success rates were 96.9% (62 of 64) and 100%, respectively. There were no perioperative mortalities. Local recurrence was identified in 5 tumors (7.8%), with no significant differences among tumor sizes (P = .662): < 3 cm (9.3%), 3-5 cm (0%), and > 5 cm (8.3%). Median estimated overall survival (OS) from first stereotactic ablation treatment was 29.3 months ± 8.9 (95% confidence interval [CI], 11.9-46.8 mo; mean, 28.7 mo) after a median follow-up of 23.1 months (mean, 31.3 mo; range, 0.1-100.8 mo). No significant differences in OS (P = .223) were observed among tumor volumes < 50 cm³ (median, 84.9 mo ± 53.1; mean, 58.4 mo), 50-100 cm³ (median, 37.8 mo ± 5.7; mean, 36.3 mo), and > 100 cm³ (median, 17.1 mo ± 3.5; mean, 21.8 mo). Numbers of metastases did not affect estimated OS, with a median OS of 32.7 months ± 10.4 (mean, 35.8 mo) for single lesions vs 17.7 months ± 3.2 (mean, 25.9 mo) for 2/3 lesions and a mean of 68.4 months ± 17.23 for > 3 lesions (P = .113).

CONCLUSIONS

Multiple-electrode stereotactic RF ablation proved to be a safe minimally invasive alternative to surgical liver resection in selected patients with BCLMs.

Liver investigations: Updating on US technique and contrast-enhanced ultrasound (CEUS)

Over the past few years, the cross sectional imaging techniques (Computed Tomography - CT and Magnetic Resonance - MR) have improved, allowing a more efficient study of focal and diffuse liver diseases. Many papers had been published about the results of a routinely clinical use of the dual source/dual energy CT techniques and the use of hepatobiliary contrast agents in MR liver studies. As a consequence, these new improvements have diverted the attention away from the Ultrasound technique and its technical and conceptual evolutions. In these years of disinterest, US and especially Contrast Enhanced Ultrasound (CEUS) have consolidated and grown in their application in clinical routine for liver pathologies. In particular, thanks to the introduction of new, dedicated software packages, CEUS has allowed not only qualitative, but also quantitative analysis of lesion microcirculation, thus opening a new era in the evaluation of lesion characterization and response to therapy. Moreover, the renewed interest in liver elastography, a baseline ultrasound-based imaging modality, has led to the development of a competitive technique to assess liver stiffness and then for the evaluation of the progression towards cirrhosis, and characterization of focal liver lesions, opening the way to avoid, in selected cases, liver biopsy. The aim of this review is to offer an up-to-date overview on the state of the art of clinical applications of US and CEUS in the study of focal and diffuse liver pathologies. Besides, it aims to highlight the emerging role of perfusion techniques in the assessment of local and systemic treatment response and to show how the liver evolution from steatosis to fibrosis can be revealed by elastography.

Planning and guidance: New tools to enhance the human skills in interventional oncology

Navigation systems have the potential to achieve a high accuracy for percutaneous ablation of tumors even for those in difficult locations. In the last years, successful research has been conducted to make navigation devices applicable to percutaneous tumor ablation with special planning software that now allows high accuracy even for deep-located small lesions close to critical structures. Because of the high number of available navigation systems, this review focuses on those with preexisting clinical studies.

Comparison of real-time contrast-enhanced ultrasonography and standard ultrasonography in liver cancer microwave ablation

Primary liver cancer has a high incidence and high mortality rates, and currently the only viable option is surgery, although there are a number of difficulties related to this method. The aim of the present study was to investigate the potential advantages of the real-time contrast-enhanced ultrasonography (CEUS) for microwave ablation of primary liver cancer. One hundred patients with primary liver cancer were included in the study. The patients were divided into the ordinary ultrasonography and the CEUS groups. For the ordinary ultrasonography group, the ordinary ultrasonography-guided microwave ablation method was used, while microwave ablation under the guidance of CEUS was conducted for the CEUS group. The size of lesions and clearness of the tumor boundary prior to surgery in the two groups were compared. Additionally, postoperative complications and the survival rate were monitored. Lesion boundary areas measured by CEUS were significantly larger than those measured with ordinary ultrasonography. The incidence rate of postoperative pain, fever, intra-abdominal hemorrhage and infection and other complications in the ordinary ultrasonography group were significantly higher than that in the CEUS group. The tumor recurrence rate in the CEUS group was significantly lower than that in the ordinary ultrasonography group. Seventy-two percent of patients in the CEUS group showed no progress, compared to 48% of in the ordinary ultrasonography group. The progress-free survival rate in the CEUS group after 6 months was significantly higher than that in the ordinary ultrasonography group. Disease-free survival time in the CEUS group was considerably longer than the control group. In conclusion, the guidance of real-time CEUS on the primary liver cancer microwave ablation treatment can achieve good intra-operative results. It offers a real-time guidance effect, improves survival time and reduces the incidence of complications.

Clinical experience with cone-beam CT navigation for tumor ablation

PURPOSE

To describe clinical use and potential benefits of cone-beam computed tomography (CT) navigation to perform image-guided percutaneous tumor ablation.

MATERIALS AND METHODS

All ablations performed between February 2011 and February 2013 using cone-beam CT navigation were included. There were 16 patients who underwent 20 ablations for 29 lesions. Cone-beam CT ablation planning capabilities include multimodality image fusion and tumor segmentation for visualization, depiction of the predicted ablation zones for intraprocedural planning, and segmentation of the ablated area for immediate verification after treatment. Number and purpose of cone-beam CT scans were examined. The initial ablation plan, defined as number of probes and duration of energy delivery, was recorded for the 20 of the 29 lesions ablated. Technical success and local recurrences were recorded. Primary and secondary effectiveness rates were calculated.

RESULTS

Image fusion was used for 16 lesions, and intraprocedural ultrasound was used for 4 lesions. Of the 20 ablations, where the ablation plans were recorded, there was no deviation from the plan in 14 ablations. In the remaining 6 ablations, iterative planning was needed for complete tumor coverage. An average of 8.7 cone-beam CT scans ± 3.2 were performed per procedure, including 1.3 ± 0.5 for tumor segmentation and planning, 1.7 ± 0.7 for probe position confirmation, and 3.9 ± 2 to ensure complete coverage. Mean follow-up time was 18.6 months ± 6.5. Ablations for 28 of 29 lesions were technically successful (96.5%). Of ablations performed with curative intent, technical effectiveness at 1 month was 25 of 26 lesions (96.1%) and 22 of 26 lesions (84.6%) at last follow-up. Local tumor progression was observed in 11.5% (3 of 26 lesions).

CONCLUSIONS

Cone-beam CT navigation may add information to assist and improve ablation guidance and monitoring.

Comparison of the effectiveness and safety of ultrasound- and CT-guided percutaneous radiofrequency ablation of non-operation hepatocellular carcinoma

To retrospectively compare the effectiveness and safety of ultrasound (US)- and computer tomography (CT)-guided percutaneous radiofrequency ablation (PRFA) in treating patients with non-operation hepatocellular carcinoma (HCC). Forty patients with non-operation HCC who were treated with US-guided PRFA (20 patients with 24 HCC lesions) or CT-guided PRFA (20 patients with 27 HCC lesions) were enrolled in this study. Follow-up was performed with US and CT/MRI. Complete ablation rate, local recurrence rate, and overall survival rate were used to evaluate the efficacy of the two therapeutic choices. The PRFA-related complications including hilar bile duct injury, sepsis, liver failure, renal dysfunction, peritoneal hemorrhage, and skin burn were assessed. The operation time of CT-guided group was significantly longer than that of the US-guided group (P < 0.05). The single ablation times for tumors with similar size showed no significant difference between the two groups (P > 0.05). The differences in complete ablation rate (79.2 vs. 88.9 %, P > 0.05) and local recurrence rate (16.7 vs. 14.8 %, P > 0.05) between US- and CT-guided groups were not statistically significant. In the US-guided group, the 1-, 2-, and 3-year overall survival rates were 85, 74, and 68 %, respectively, while they were 84, 72, and 58 % in the CT-guided group. The differences were not statistically significant (P > 0.05). No severe complications were found in the two groups. Both US- and CT-guided PRFA are safe and effective therapies for patients with HCC when surgical options are precluded.

Role of local ablative therapy for hepatocellular carcinoma

Percutaneous local ablation (PLA) techniques are currently considered as the best treatment option for patients with early-stage hepatocellular carcinoma (HCC) who are not candidates for surgical resection. They are safe, minimally invasive, efficacious and cost-effective. Radiofrequency ablation (RFA) is considered as the first line treatment in some centers, though most of the guidelines recommend it for small HCCs, where surgical resection is not feasible. In developing countries percutaneous ethanol injection (PEI) and percutaneous acetic acid injection (PAI) may be used instead of RFA. For large HCCs, advances in electrode designs and newer techniques of ablation, including microwave ablation, are increasingly been used. Combination treatment modalities have shown promising results as compared to single modality for large tumors. The selection of the most appropriate modality depends on the size, number of lesions, the liver function status, patient's financial resources, availability of a particular technique and the expertise available.

Radiofrequency ablation for intrahepatic recurrent hepatocellular carcinoma: long-term results and prognostic factors in 168 patients with cirrhosis

PURPOSE

To analyze the clinical outcome of radiofrequency ablation (RFA) for recurrent intrahepatic hepatocellular carcinoma (HCC) after variable first-line treatment.

MATERIALS AND METHODS

From January 2006 to December 2007, 168 consecutive patients (133 male, 35 female; mean age 66.7 ± 10.1 years) with cirrhosis (Child-Pugh class A/B [146/22]) who underwent RFA for treatment for recurrent intrahepatic HCC ≤5 cm, and in up to three nodules (214 HCCs; mean diameter 20.8 ± 7.5 mm; 38 multinodular forms), were included. Univariate and multivariate analyses for potential clinical, tumor-related, and radiologic factors affecting overall and recurrence-free patient survival were performed using the Cox proportional hazard model.

RESULTS

Major complications occurred in 5 patients (5 of 168, 3.0 %), although there were no procedure-related deaths. Complete ablation was achieved in 161 patients (161 of 168, 95.8 %). After a mean follow-up period of 4 ± 21 months, local tumor progression, distant intrahepatic recurrence, and extrahepatic metastasis occurred in 22, 132, and 41 patients, respectively. Overall 5-year survival and recurrence-free survival were 48.0 and 11.9 %, respectively. Significant predicting factors for overall patient survival were Child-Pugh class B (relative risk [RR] = 4.52, 95 % confidence interval [CI] 1.97-10.34; P < 0.001), serum alpha-fetoprotein (AFP) level (RR = 1.01, 95 % CI 1.01-1.01; P < 0.001), number of HCC nodules (RR = 1.70, 95 % CI 1.04-2.76; P = 0.033), tumor size (RR = 1.40, 95 % CI 1.07-1.83; P = 0.014), and presence of portosystemic collaterals (RR = 1.78, 95 % CI 1.09-2.92; P = 0.022).

CONCLUSION

RFA is a safe and effective treatment modality for recurrent intrahepatic HCC and has a 5-year survival rate of 48.0 %. Serum AFP level, Child-Pugh class, tumor number and size, and presence of portosystemic collaterals significantly affect overall patient survival.

Meta-analysis of radiofrequency ablation in combination with transarterial chemoembolization for hepatocellular carcinoma

AIM: To compare radiofrequency ablation (RFA) and transcatheter arterial chemoembolization (TACE) with RFA monotherapy in hepatocellular carcinoma (HCC).

METHODS: We searched PubMed, Medline, Embase and Chinese databases (CBMdisc and Wanfang data) for randomized controlled trails comparing RFA plus TACE and RFA alone for treatment of HCC from January 2000 to December 2012. The overall survival rate, recurrence-free survival rate, tumor progression rate, and safety were analyzed and compared. The analysis was conducted on dichotomous outcomes and the standard meta-analytical techniques were used. Pooled odds ratios (ORs) with 95%CIs were calculated using either the fixed-effects or random-effects model. For each meta-analysis, the χ² and I² tests were first calculated to assess the heterogeneity of the included trials. For P < 0.05 and I² > 50%, the assumption of homogeneity was deemed invalid, and the random-effects model was used; otherwise, data were assessed using the fixed-effects model. All statistical analysis was conducted using Review manager (version 4.2.2.) from the Cochrane collaboration.

RESULTS: Eight randomized controlled trials were identified as eligible for inclusion in this analysis and included 598 patients with 306 treated with RFA plus TACE and 292 with RFA alone. Our data analysis indicated that RFA plus TACE was associated a significantly higher overall survival rate (OR_1-year = 2.96, 95%CI: 1.84-7.74, P < 0.001; OR_2-year = 3.72, 95%CI: 1.24-11.16, P = 0.02; OR_3-year = 2.65, 95%CI: 1.81-3.86, P < 0.001) and recurrence-free survival rate (OR_3-year = 3.00, 95%CI: 1.75-5.13, P < 0.001; OR_5-year = 2.26, 95%CI: 1.43-3.57, P = 0.0004) vs that of RFA alone. The tumor progression rate in patients treated with RFA alone was higher than that of RFA plus TACE (OR = 0.60, 95%CI: 0.42-0.88, P = 0.008) and there was no significant difference on major complications between two different kinds of treatment (OR = 1.20, 95%CI: 0.31-4.62, P = 0.79). Additionally, the meta-analysis data of subgroups revealed that the survival rate was significantly higher in patients with intermediate- and large-size HCC underwent RFA plus TACE than in those underwent RFA monotherapy; however, there was no significant difference between RFA plus TACE and RFA on survival rate for small HCC.

CONCLUSION: The combination of RFA with TACE has advantages in improving overall survival rate, and provides better prognosis for patients with intermediate- and large-size HCC.

[Radiofrequency ablation of hepatocellular carcinoma]

Percutaneous radiofrequency ablation (RFA) is well established in the treatment of hepatocellular carcinoma (HCC). Due to its curative potential, it is the method of choice for non resectable BCLC (Barcelona Liver Clinic) 0 and A. RFA challenges surgical resection for small HCC and is the method of choice in bridging for transplantation and recurrence after resection or transplantation. The technical feasibility of RFA depends on the size and location of the HCC and the availability of ablation techniques (one needle techniques, multi-needle techniques). More recently, stereotactic multi-needle techniques with 3D trajectory planning and guided needle placement substantially improve the spectrum of treatable lesions including large volume tumors. Treatment success depends on the realization of ablations with large intentional margins of tumor free tissue (A0 ablation in analogy to R0 resection), which has to be documented by fusion of post- with pre-ablation images, and confirmed during follow-up imaging.

Novel approaches to treatment of hepatocellular carcinoma and hepatic metastases using thermal ablation and thermosensitive liposomes

Because of the limitations of surgical resection, thermal ablation is commonly used for the treatment of hepatocellular carcinoma and liver metastases. Current methods of ablation can result in marginal recurrences of larger lesions and in tumors located near large vessels. This review presents a novel approach for extending treatment out to the margins where temperatures do not provide complete treatment with ablation alone, by combining thermal ablation with drug-loaded thermosensitive liposomes. A history of the development of thermosensitive liposomes is presented. Clinical trials have shown that the combination of radiofrequency ablation and doxorubicin-loaded thermosensitive liposomes is a promising treatment.

[Stereotactic Radiofrequency Ablation (SRFA) of intrahepatic cholangiocellular carcinomas: a minimal invasive alternative to liver resection]

Up to now resection and liver transplantation are concerned as the only curative treatment options for intrahepatic cholangiocellular carcinomas (ICCs). For patients with inoperable ICCs systemic chemotherapy and various locoregional therapies including transarterial (chemo)embolization (TACE), selective internal radiation therapy (SIRT), radiofrequency ablation (RFA) and microwave ablation (MWA) are applied. Stereotactic RFA (SRFA) allows for precise 3D planning and positioning of multiple RF electrodes. Due to overlapping necroses tumors > 5 cm can be completely ablated in one session. 17 inoperable consecutive patients with 52 ICCs were treated with stereotactic RFA (SRFA). A median overall survival of 60 months was achieved. The two largest tumors with diameters > 10 cm were completely ablated. These SRFA data of irresectable ICCs are superior to the published data on resection. SRFA is a minimal invasive alternative treatment to resection and may be considered as the first-line local treatment of patients with ICCs in selected patients.

Percutaneous stereotactic radiofrequency ablation of colorectal liver metastases

OBJECTIVES

To evaluate the outcome of patients with colorectal liver metastasis (CRLM) treated with stereotactic radiofrequency ablation (SRFA).

METHODS

Following IRB approval, a retrospective evaluation of 98 SRFA treatment sessions of 189 CRLMs in 63 consecutive patients was performed. Local recurrence rate (LR), overall survival (OS) and disease-free survival (DFS) were analysed.

RESULTS

LR was identified in 16% of the tumours (31/189), with no significant differences (P = 0.635) when comparing tumour sizes <3 cm (17.7%), 3-5 cm (11.1%) and >5 cm (17.4%). The median OS from SRFA treatment was 33.2 months after a mean follow-up of 25 months (range 2-66); the corresponding 1-, 3- and 5- year survival rates were 87%, 44% and 27%. The median OS was significantly different when comparing unresectable and resectable patients (27 vs. 58 months, P = 0.002) with OS rates of 92%, 66% and 48% at 1, 3 and 5 years in resectable patients. Tumour size did not affect OS and DFS.

CONCLUSION

Due to the favourable outcome, SRFA challenges resection as first-line local treatment of patients with CRLM. As long as randomised studies are pending, we recommend entering an individual decision-making process with every patient.

KEY POINTS

Large colorectal liver metastases can be effectively treated by stereotactic radiofrequency ablation (SRFA). Using SRFA the overall survival is not affected by tumour size. SRFA achieves similar overall and disease-free survival rates as surgical resection. SRFA challenges surgical resection as the first-line treatment for colorectal liver metastases.

Stereotactic radiofrequency ablation of unresectable intrahepatic cholangiocarcinomas: a retrospective study

PURPOSE

To evaluate treatment effects, complications, and outcome of percutaneous stereotactic radiofrequency ablation (SRFA) of intrahepatic cholangiocarcinoma (ICC).

PATIENTS AND METHODS

Eleven consecutive patients (nine men and two women) with a total of 36 inoperable ICCs (18 initial lesions, 16 lesions newly detected during follow-up, and two local recurrences) underwent SRFA between December 2004 and June 2010. Two different radiofrequency ablation (RFA) devices with internally cooled electrodes were used. Tumor diameters ranged from 0.5 to 10 cm (median 3.0 cm). A total of 23 SRFA sessions were performed. The efficacy of SRFA was evaluated by contrast-enhanced computed tomography or magnetic resonance imaging 1 month after treatment and then every 3 months.

RESULTS

Primary technical effectiveness rate was 92%. Further follow-up every 3 months revealed three local recurrences (8%), two of which were successfully retreated, resulting in a secondary technical effectiveness rate of 98%. After a total of 23 RFA sessions, three major complications occurred (13%) that could be managed interventionally. Mean follow-up time was 35 months (range 12-81 months). One- and 3-year overall survival rates were 91 and 71%, respectively. The median overall survival was 60 months (according to the life table method). Eight (73%) of 11 patients were still alive at the end of follow-up.

CONCLUSION

SRFA is effective in the treatment of unresectable ICC even if the tumor is large and located close to major vessels. SRFA shows a survival benefit compared to other palliative treatment options and may also be considered as the first-line local treatment of ICCs in selected patients.