Hepatic Tumor Ablation

Transvaginal radiofrequency ablation: a therapeutic option for managing symptomatic uterine fibroids in women with reproductive desires

Objective

To evaluate whether transvaginal radiofrequency (RF) ablation of fibroids is a technique that can be offered to women with reproductive desires.

Design

Unicentric, prospective, observational study.

Setting

University Hospital.

Patients

Twenty-seven individuals who desired to become mothers after undergoing RF ablation for symptomatic fibroids.

Interventions

Transvaginal RF ablation for symptomatic fibroids with a maximum total volume of 145 cm3.

Main Outcome Measures

The reduction in the size of the fibroids, improvement of symptoms, and reproductive outcomes during the 24 months after the ablation. For patients who achieved pregnancy, we assessed the type of conception, course of gestation, type of delivery, neonatal outcomes, and occurrence of both maternal and fetal complications.

Results

A statistically significant reduction in symptoms related to the fibroids 6 months after the ablation was demonstrated through the implementation of the Symptom Severity Scale. No patient required hospitalization after the procedure, and on average from the third day after intervention, they resumed their work activities without the need for analgesics. Among those patients who attempted pregnancy during the 24-month follow-up period, 73.68 % (14/19) achieved motherhood. There were no cases of uterine rupture, premature birth, or intrauterine fetal death.

Conclusions

Radiofrequency ablation for fibroids seems to be a promising, safe, and low-complexity alternative that does not appear to interfere with the development of a normal term gestation.

Less contrast, more clarity, innovative visualization technique for management of multiple colorectal liver metastases using microwave ablation through a portal venous access

Colorectal cancer, a leading cause of cancer-related deaths, often results in liver metastases, with about half of patients affected. For those ineligibles for surgery, percutaneous microwave ablation (MWA) offers a viable alternative. Conventionally, visualizing liver lesions prior to MWA demands significant IV contrast, often needing repeated sessions. We introduce a technique using minimal IV contrast to treat multiple metastatic lesions simultaneously. A case of a 47-year-old male with stage 4 colorectal adenocarcinoma and multiple liver metastases is presented. Instead of the typical 100-150 cc of IV contrast, our method used just 25 cc, successfully ablating 6 hepatic metastases in 1 session. This approach not only reduces contrast volume but also optimizes treatment efficiency.

Ultrasound single-phase CBE imaging for monitoring radiofrequency ablation of the liver tumor: A preliminary clinical validation

Radiofrequency ablation (RFA) is an alternative treatment for early-stage hepatocellular carcinoma (HCC). The production of gas bubbles by RFA indicates threshold temperature of tissue necrosis and results in changes in backscattered energy (CBE) when ultrasound monitors RFA. In this study, ultrasound single-phase CBE imaging was used as a means of monitoring RFA of the liver tumor by analyzing the backscattering of ultrasound from gas bubbles in the liver. A total of 19 HCC patients were enrolled in the study. An ultrasound system was used during RFA to monitor the ablation process and acquire raw image data consisting of backscattered signals for single-phase CBE imaging. On the basis of single-phase CBE imaging, the area corresponding to the range of gas bubbles was compared with the tumor sizes and ablation zones estimated from computed tomography. During RFA, ultrasound single-phase CBE imaging enabled improved visualization of gas bubbles. Measured gas bubble areas by CBE were related to tumor size (the Spearman correlation coefficient r_s = 0.86; p < 0.05); less dependent on the ablation zone. Approximately 95% of the data fell within the limits of agreement in Bland-Altman plots, and 58% of the data fell within the 95% CI. This study suggests that single-phase CBE imaging provides information about liver tumor size because of the abundant vessels in liver tumors that promote the generation of gas bubbles, which serve as natural contrast agents in RFAs to enhance ultrasound backscattering. Ultrasound single-phase CBE imaging may allow clinicians to determine if the required minimum RFA efficacy level is reached by assessing gas bubbles in the liver tumors.

Microwave ablation for colorectal cancer metastasis to the liver: a single-center retrospective analysis

Background

The purpose of this study is to evaluate the safety and intermediate-term efficacy of percutaneous microwave (MW) ablation for the treatment of colorectal liver metastases (CRLM) at a single institution.

Methods

A retrospective review was performed of all CRLM treated with MW ablation from 3/2011 to 7/2020 (102 tumors; 72 procedures; 57 patients). Mean age was 60 years (range, 36-88) and mean tumor size was 1.8 cm (range, 0.5-5.0 cm). The patient population included 19 patients with extra-hepatic disease. Chemotherapy (pre- and/or post-ablation) was given in 98% of patients. Forty-five sessions were preceded by other focal CRLM treatments including resection, ablation, radiation, and radioembolization. Kaplan-Meier curves were used to estimate local tumor progression-free survival (LTPFS), disease-free survival (DFS), and overall survival (OS) and multivariate analysis (Cox Proportional Hazards model) was used to test predictors of OS.

Results

Technical success (complete ablation) was 100% and median follow-up was 42 months (range, 1-112). There was a 4% major complication rate and an overall complication rate of 8%. Local tumor progression (LTP) rate during the entire study period was 4/98 (4%), in which 2 were retreated with MW ablation for a secondary LTP-rate of 2%. LTP-free survival at 1, 3, and 5 years was 93%, 58%, and 39% and median LTP-free survival was 48 months. OS at 1, 3, and 5 years was 96%, 66%, 47% and median OS was 52 months. There were no statistically significant predictors of OS.

Conclusions

MW ablation of hepatic colorectal liver metastases appears safe with excellent local tumor control and prolonged survival compared to historical controls in selected patients. Further comparative studies with other local treatment strategies appear indicated.

A Systematic Review of the Treatment of Uterine Myomas Using Transcervical Ultrasound-Guided Radiofrequency Ablation with the Sonata System

OBJECTIVE

To evaluate the treatment success, possible side effects, and safety of radiofrequency ablation with the Sonata System.

DATA SOURCES

An electronic literature search in the PubMed and Medline databases was carried out from inception to August 2020.

METHODS OF STUDY SELECTION

The review was performed in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Keywords such as "Sonata," "transcervical ablation," and "uterine myoma" were used to identify all relevant articles independently by both authors. Full-text articles in English that reported at least 1 of the following outcomes were included in the study: reduction in perfused/total myoma volume, effect of treatment on bleeding intensity and myoma-related symptoms, number of surgical reinterventions, adverse events, return to activities of daily life, effects on surrounding tissue, and safety during pregnancy.

TABULATION, INTEGRATION, AND RESULTS

10 studies matching the inclusion criteria were identified and used for further analysis. A reduction in total and perfused myoma volume of 63.2% and 64.5% was achieved. One of the studies showed a 53.8 ± 50.5% (n = 48) reduction in Menstrual Pictogram Score, and another study showed a 51.1 ± 40.9% (n = 142) reduction in Pictorial Blood Loss Assessment Chart at 12 months. 87.2% (n = 190) of the patients reported a clinically meaningful reduction in menstrual blood loss after 12 months. While Symptom Severity Scores dropped by 28.8 ± 19.3, 23.3 ± 23.7, and 23.7 ± 19.4 points at 3, 6, and 12 months, respectively, Health-Related Quality of Life Scores increased to 77.5 ± 22.0, 82.8 ± 19.0, and 83.3 ± 20.5 points. One study had an 8% reintervention rate after 12 months, and another study showed a 0.7% and 5.2% rate after 12 and 24 months. After an average of 64 months after ablation, the reintervention rate was 11.8%. Time to return to activities of daily life was 2.9 ± 2.5 days. No related complications during pregnancy and delivery were reported.

CONCLUSION

Radiofrequency ablation with the Sonata System represents a minimally invasive, organ-preserving treatment option in patients with symptomatic uterine myomas, associated with clinically meaningful improvement of myoma-related symptoms.

The development of a predictive risk model on post-ablation hemobilia: a multicenter matched case-control study

Objective:

This study aimed to develop a predictive risk model for post-ablation hemobilia.

Methods:

This was a retrospective, multicenter, matched case–control study. The case group comprised patients with hepatocellular carcinoma who developed post-ablation hemobilia (n = 21); the control group (n = 63) comprised patients with hepatocellular carcinoma but no post-ablation hemobilia; for each case, we included three controls matched for age, sex, platelet count, year of ablation therapy, and center. Univariate and multivariate regression analyses were performed to identify the risk factors for hemobilia. A risk score model was developed based on adjusted odds ratios (ORs).

Results:

The independent risk factors for occurrence of post-ablation hemobilia were maximum tumor diameter >47 mm [OR = 5.983, 95% CI (1.134–31.551)] and minimum distance from the applicator to the portal trunk ≤8 mm [OR = 4.821, 95% CI (1.225–18.975)]. The risk model was developed using the adjusted ORs; thus a score of 6 was assigned to the former and a score of 5 for the latter. The area under the curve of this risk model was 0.76. Significant hemodynamic instability and inaccurate embolization might increase the risk of recurrence of hemobilia.

Conclusion:

Tumor size >47 mm and distance of the applicator from the portal trunk ≤8 mm are independent risk factors for hemobilia. A predictive risk model for post-ablation hemobilia was developed using these risk factors.

Advances in knowledge:

This is the first study that developed a risk score model of post-ablation hemobilia. Risk factors of the recurrence of post-ablation hemobilia were also been identified.

Robotically Assisted Sonic Therapy (RAST) for Noninvasive Hepatic Ablation in a Porcine Model: Mitigation of Body Wall Damage with a Modified Pulse Sequence

PURPOSE

Robotically assisted sonic therapy (RAST) is a nonthermal, noninvasive ablation method based on histotripsy. Prior animal studies have demonstrated the ability to create hepatic ablation zones at the focal point of an ultrasound therapy transducer; however, these treatments resulted in thermal damage to the body wall within the path of ultrasound energy delivery. The purpose of this study was to evaluate the efficacy and safety of a pulse sequence intended to mitigate prefocal body wall injury.

MATERIALS AND METHODS

Healthy swine (n = 6) underwent hepatic RAST (VortxRx software version 1.0.1.3, HistoSonics, Ann Arbor MI) in the right hepatic lobe. A 3.0 cm spherical ablation zone was prescribed for each. Following treatment, animals underwent MRI which was utilized for ablation zone measurement, evaluation of prefocal injury, and assessment of complications. Each animal was euthanized, underwent necropsy, and the tissue was processed for histopathologic analysis of the ablation zone and any other sites concerning for injury.

RESULTS

No prefocal injury was identified by MRI or necropsy in the body wall or tissues overlying the liver. Ablation zones demonstrated uniform cell destruction, were nearly spherical (sphericity index = 0.988), and corresponded closely to the prescribed size (3.0 × 3.1 × 3.4 cm, p = 0.70, 0.36, and 0.01, respectively). Ablation zones were associated with portal vein (n = 3, one occlusive) and hepatic vein thrombosis (n = 4, one occlusive); however, bile ducts remained patent within ablation zones (n = 2).

CONCLUSIONS

Hepatic RAST performed with a modified ultrasound pulse sequence in a porcine model can mitigate prefocal body wall injuries while maintaining treatment efficacy. Further study of hepatic RAST appears warranted, particularly in tumor models.

Two-dimensional ultrasound-computed tomography image registration for monitoring percutaneous hepatic intervention

PURPOSE

Deformable registration of ultrasound (US) and contrast enhanced computed tomography (CECT) images are essential for quantitative comparison of ablation boundaries and dimensions determined using these modalities. This comparison is essential as stiffness-based imaging using US has become popular and offers a nonionizing and cost-effective imaging modality for monitoring minimally invasive microwave ablation procedures. A sensible manual registration method is presented that performs the required CT-US image registration.

METHODS

The two-dimensional (2D) virtual CT image plane that corresponds to the clinical US B-mode was obtained by "virtually slicing" the 3D CT volume along the plane containing non-anatomical landmarks, namely points along the microwave ablation antenna. The initial slice plane was generated using the vector acquired by rotating the normal vector of the transverse (i.e., xz) plane along the angle subtended by the antenna. This plane was then further rotated along the ablation antenna and shifted along with the direction of normal vector to obtain similar anatomical structures, such as the liver surface and vasculature that is visualized on both the CT virtual slice and US B-mode images on 20 patients. Finally, an affine transformation was estimated using anatomic and non-anatomic landmarks to account for distortion between the colocated CT virtual slice and US B-mode image resulting in a final registered CT virtual slice. Registration accuracy was measured by estimating the Euclidean distance between corresponding registered points on CT and US B-mode images.

RESULTS

Mean and SD of the affine transformed registration error was 1.85 ± 2.14 (mm), computed from 20 coregistered data sets.

CONCLUSIONS

Our results demonstrate the ability to obtain 2D virtual CT slices that are registered to clinical US B-mode images. The use of both anatomical and non-anatomical landmarks result in accurate registration useful for validating ablative margins and comparison to electrode displacement elastography based images.

The Role of a Curved Electrode with Controllable Direction in the Radiofrequency Ablation of Liver Tumors Behind Large Vessels

PURPOSE

To investigate the role of a novel curved radiofrequency ablation (RFA) electrode with controllable direction in the ablation of tumors behind large hepatic vessels in ex vivo bovine and in vivo canine liver experiments.

MATERIALS AND METHODS

Approval from the institutional animal care and use committee was obtained. In ex vivo experiments, conventional multi-tines expandable electrodes, conventional monopolar straight electrodes and novel curved electrodes were used in the ablation of the bovine liver (n = 90). The ablated area, parallel axis, vertical axis and shape of different electrodes were compared. Then, 24 beagle dogs (10 months old, female) were used for in vivo experiments. Visual tumor targets deeply located in the portal vein were established, and ultrasound-guided liver ablation was performed with different electrodes. The ablation range, target coverage rate, percentage of normal tissue injury and damage to adjacent vessels were evaluated. The Kruskal-Wallis test and the Chi-squared test were used for statistical analysis.

RESULTS

For the ex vivo study with a 3-cm electrode, the ablation area of the multi-tines expandable electrode group (7.14 ± 0.16 cm²) was significantly larger than that of the novel curved electrode group (5.01 ± 0.30 cm², P < 0.001) and the monopolar straight electrode group (5.43 ± 0.15 cm², P < 0.001). The results obtained with the 4-cm electrode in the three groups were in accordance with those of the 3-cm electrode. In vivo, the normal tissue damage area of the novel curved electrode group was smaller than that of the multi-tines expandable electrode group (1.10 ± 0.18 cm² vs. 4.00 ± 0.18 cm², P < 0.001). The target coverage rate of the novel curved electrode group was better than that of the monopolar straight electrode group (100% vs. 80.86 ± 1.68%, P < 0.001). The hematoxylin and eosin (H&E) and TUNEL staining results showed that the ablation necrosis area was adjacent to large vessels, but the vascular wall was not significantly damaged in the novel curved electrode group.

CONCLUSION

Our preliminary results showed that the novel curved RFA electrode with controllable direction could achieve accurate ablation for tumors behind large hepatic vessels, with a better target coverage rate and less damage to normal tissue, than conventional multi-tines expandable electrodes and monopolar straight electrodes.

A novel 3-dimensional electromagnetic guidance system increases intraoperative microwave antenna placement accuracy

BACKGROUND

Failure to locate lesions and accurately place microwave antennas can lead to incomplete tumor ablation. The Emprint™ SX Ablation Platform employs real-time 3D-electromagnetic spatial antenna tracking to generate intraoperative laparoscopic antenna guidance. We sought to determine whether Emprint™ SX affected time/accuracy of antenna-placement in a laparoscopic training model.

METHODS

Targets (7-10 mm) were set in agar within a laparoscopic training device. Novices (no surgical experience), intermediates (surgical residents), and experts (HPB-surgeons) were asked to locate and hit targets using a MWA antenna (10-ultrasound only, 10-Emprint™ SX). Time to locate target, number of attempts to hit the target, first-time hit rate, and time from initiating antenna advance to hitting the target were measured.

RESULTS

Participants located 100% of targets using ultrasound, with experts taking significantly less time than novices and intermediates. Using ultrasound only, successful hit-rates were 70% for novices and 90% for intermediates and experts. Using Emprint™ SX, successful hit rates for all 3-groups were 100%, with significantly increased first-time hit-rates and reduced time required to hit targets compared to ultrasound only.

DISCUSSION

Emprint™ SX significantly improved accuracy and speed of antenna-placement independent of experience, and was particularly beneficial for novice users.

Delineation of Post-Procedure Ablation Regions with Electrode Displacement Elastography with a Comparison to Acoustic Radiation Force Impulse Imaging

We compared a quasi-static ultrasound elastography technique, referred to as electrode displacement elastography (EDE), with acoustic radiation force impulse imaging (ARFI) for monitoring microwave ablation (MWA) procedures on patients diagnosed with liver neoplasms. Forty-nine patients recruited to this study underwent EDE and ARFI with a Siemens Acuson S2000 system after an MWA procedure. On the basis of visualization results from two observers, the ablated region in ARFI images was recognizable on 20 patients on average in conjunction with B-mode imaging, whereas delineable ablation boundaries could be generated on 4 patients on average. With EDE, the ablated region was delineable on 40 patients on average, with less imaging depth dependence. Study of tissue-mimicking phantoms revealed that the ablation region dimensions measured on EDE and ARFI images were within 8%, whereas the image contrast and contrast-to-noise ratio with EDE was two to three times higher than that obtained with ARFI. This study indicated that EDE provided improved monitoring results for minimally invasive MWA in clinical procedures for liver cancer and metastases.

A New Paradigm for Uterine Fibroid Treatment: Transcervical, Intrauterine Sonography-Guided Radiofrequency Ablation of Uterine Fibroids with the Sonata System

Purpose of Review

This article provides the current evidence related to transcervical radiofrequency ablation of uterine fibroids under integrated intrauterine sonography guidance (the Sonata System).

Recent Findings

Published data on the treatment of fibroids with the Sonata System has demonstrated significant median reductions in total (73.3%) and perfused (73.3%) uterine fibroid volume, menstrual bleeding (72.3%), symptom severity (62.5%), and improvements in health-related quality of life (127%) at 12 months post-ablation. A clinical trial under an FDA Investigational Device Exemption is in progress.

Summary

The Sonata System is a promising treatment modality for uterine fibroids. As an incisionless, minimally invasive treatment that does not require general anesthesia or hospitalization, it has the potential for redefining the current paradigm for management of symptomatic fibroids.

Advantage of sorafenib combined with radiofrequency ablation for treatment of hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of death worldwide. Among the surgical and nonsurgical treatments available, radiofrequency ablation (RFA) and sorafenib have been shown to have efficacy. There is little evidence whether combination of these therapies would have additional benefits.

METHODS

In a mouse model of HCC, effects of sorafenib were determined by tumor size, RFA-induced necrosis area (triphenyltetrazolium chloride staining), microvascular density (MVD; 4',6-diamidino-2-phenylindole and anti-CD31 antibody staining), and tumor perfusion (magnetic resonance imaging).

RESULTS

The RFA-induced necrosis area was 80.98 ± 9.14 and 69.49 ± 7.46 mm2 in mice administered 80 and 40 mg/kg sorafenib, respectively, but only 57.29 ± 3.39 mm2 in controls. Sorafenib also reduced tumor volume and enhanced RFA-induced tumor destruction in a dose-dependent manner, and reduced both MVD and tumor perfusion.

CONCLUSIONS

The results of our study suggest a potential role for combining RFA with sorafenib for treatment of HCC. Sorafenib could enhance RFA efficiency, possibly through its angiogenesis suppressive effects.

Locoregional Therapies of Cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CC) is the second most primary liver malignancy with increasing incidence in Western countries. Currently, surgical R0 resection is regarded as the only potentially curative treatment. The results of systemic chemotherapy and best supportive care (BSC) in patients with metastatic disease are often disappointing in regard to toxicity, oncologic efficacy, and overall survival. In current practice, the use of different locoregional therapies is increasingly more accepted.

METHODS

A review of the literature on locoregional therapies for intrahepatic cholangiocarcinoma (ICC) was undertaken.

RESULTS

There are no prospective randomized controlled trials. For localized ICC, either primary or recurrent, radiofrequency ablation (RFA) is by far the most commonly used thermal ablation modality. Thereby, a systematic review and meta-analysis reports major complication in 3.8% as well as 1-, 3-, and 5-year overall survival rates of 82, 47, and 24%, respectively. In selected patients (e.g. with a tumor diameter of ≤3 cm), oncologic efficacy and survival after RFA are comparable with surgical resection. For diffuse ICC, different transarterial therapies, either chemotherapy-based (hepatic artery infusion (HAI), transarterial chemoembolization (TACE)) or radiotherapy-based (transarterial radioembolization (TARE)), show extremely promising results. With regard to controlled trials (transarterial therapy versus systemic chemotherapy, BSC or no treatment), tumor control is virtually always better for transarterial therapies and very often accompanied by a dramatic survival benefit and improvement of quality of life. Of note, the latter is the case not only for patients without extrahepatic metastatic disease but also for those with liver-dominant extrahepatic metastatic disease. There are other locoregional therapies such as microwave ablation, irreversible electroporation, and chemosaturation; however, the current data support their use only in controlled trials or as last-line therapy.

CONCLUSION

Dedicated locoregional therapies are commonly used for primary and recurrent ICC as well as liver-only and liver-dominant extrahepatic metastatic disease. Currently, the best evidence and most promising results are available for RFA, HAI, TACE, and TARE. In cohort studies, the overall survival rates are similar to those obtained with surgery or systemic therapies. Prospective randomized controlled trials are warranted to compare safety and efficacy between different surgical, interventional, and systemic therapies, as well as their combinations.

Post-Procedure Evaluation of Microwave Ablations of Hepatocellular Carcinomas Using Electrode Displacement Elastography

Microwave ablation has been used clinically as an alternative to surgical resection. However, lack of real-time imaging to assess treated regions may compromise treatment outcomes. We previously introduced electrode displacement elastography (EDE) for strain imaging and verified its feasibility in vivo on porcine animal models. In this study, we evaluated EDE on 44 patients diagnosed with hepatocellular carcinoma, treated using microwave ablation. The ablated region was identified on EDE images for 40 of the 44 patients. Ablation areas averaged 13.38 ± 4.99 cm² on EDE, compared with 7.61 ± 3.21 cm² on B-mode imaging. Contrast and contrast-to-noise ratios obtained with EDE were 232% and 98%, respectively, significantly higher than values measured on B-mode images (p < 0.001). This study indicates that EDE is feasible in patients and provides improved visualization of the ablation zone compared with B-mode ultrasound.