Percutaneous Tumor Ablation Research Articles

Volumetric 3D assessment of ablation zones after thermal ablation of colorectal liver metastases to improve prediction of local tumor progression.

The goal of this study was to develop and evaluate a volumetric three-dimensional (3D) approach to improve the accuracy of ablation margin assessment following thermal ablation of hepatic tumors. The 3D margin assessment technique was developed to generate the new 3D assessment metrics: volumes of insufficient coverage (VICs) measuring volume of tissue at risk post-ablation. VICs were computed for the tumor and tumor plus theoretical 5- and 10-mm margins. The diagnostic accuracy of the 3D assessment to predict 2-year local tumor progression (LTP) was compared to that of manual 2D assessment using retrospective analysis of a patient cohort that has previously been reported as a part of an outcome-centered study. Eighty-six consecutive patients with 108 colorectal cancer liver metastases treated with radiofrequency ablation (2002-2012) were used for evaluation. The 2-year LTP discrimination power was assessed using receiver operating characteristic area under the curve (AUC) analysis. A 3D assessment of margins was successfully completed for 93 out of 108 tumors. The minimum margin size measured using the 3D method had higher discrimination power compared with the 2D method, with an AUC value of 0.893 vs. 0.790 (p = 0.01). The new 5-mm VIC metric had the highest 2-year LTP discrimination power with an AUC value of 0.923 (p = 0.004). Volumetric semi-automated 3D assessment of the ablation zone in the liver is feasible and can improve accuracy of 2-year LTP prediction following thermal ablation of hepatic tumors. • More accurate prediction of local tumor progression risk using volumetric 3D ablation zone assessment can help improve the efficacy of image-guided percutaneous thermal ablation of hepatic tumors. • The accuracy of evaluation of ablation zone margins after thermal ablation of colorectal liver metastases can be improved using a volumetric 3D semi-automated assessment approach and the volume of insufficient coverage assessment metric. • The new 5-mm volume-of-insufficient-coverage metric, indicating the volume of tumor plus 5-mm margin that remained untreated, had the highest 2-year local tumor progression discrimination power.

Feasibility, efficacy, and safety of percutaneous MR-guided ablation of small (≤12 mm) hepatic malignancies.

Percutaneous tumor ablation is commonly performed using computed tomography (CT) or ultrasound (US) guidance, although reliable visualization of the target tumor may be challenging. MRI guidance provides more reliable visualization of target tumors and allows for real-time imaging and multiplanar capabilities, making it the modality of choice, in particular if lesions are small. To investigate the feasibility, technical success, and safety of percutaneous MR-guided ablation (RFA n = 27 / MWA n = 16) of small (≤12 mm) hepatic malignancies. Retrospective case study. In all, 45 patients (age: 61.1 ± 11.8) with hepatic malignancies and a lesion diameter of ≤12 mm scheduled for percutaneous MR-guided tumor ablation based on a tumor board decision were included. A 1.5T MR system was used for planning, targeting, and monitoring. Feasibility assessment included the detection of the target tumor, tumor delineation during MR-fluoroscopy guided targeting, and the number of attempts needed for precise applicator placement. Technical success was defined as successful performance of the procedure including a safety margin of 5 mm. Safety evaluation was based on procedure-related complications. Frequency. Tumor ablation (mean diameter 9.0 ± 2.1 mm) was successfully completed in 43/45 patients. Planning imaging was conducted without a contrast agent in 79% (n = 37). In 64% (n = 30), the target tumors were visible with MR-fluoroscopy. In six patients (13%), planning imaging revealed new, unexpected small lesions, which were either treated in the same session (n = 4) or changed therapy management (n = 2) due to diffuse tumor progress. Postprocedural imaging revealed a technical success of 100% (43/43), with no major complications. During follow-up, no local tumor progression was observed (mean follow-up 24.7 ± 14.0 months) although 28% (12) patients developed new hepatic lesions distant to the ablation zone. No major complications were observed. MR-guided ablation is a feasible approach for an effective and safe treatment of small hepatic malignancies. 4 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2019;49:374-381.

Expert consensus on image-guided radiofrequency ablation of pulmonary tumors: 2018 edition.

Lung cancer ranks first in incidence and mortality in China. Surgery is the primary method to cure cancer, but only 20–30% of patients are eligible for curative resection. In recent years, in addition to surgery, other local therapies have been developed for patients with numerous localized primary and metastatic pulmonary tumors, including stereotactic body radiation therapy and thermal ablative therapies through percutaneously inserted applicators. Percutaneous thermal ablation of pulmonary tumors is minimally invasive, conformal, repeatable, feasible, cheap, has a shorter recovery time, and offers reduced morbidity and mortality. Radiofrequency ablation (RFA), the most commonly used thermal ablation technique, has a reported 80–90% rate of complete ablation, with the best results obtained in tumors < 3 cm in diameter. Because the clinical efficacy of RFA of pulmonary tumors has not yet been determined, this clinical guideline describes the techniques used in the treatment of localized primary and metastatic pulmonary tumors in nonsurgical candidates, including mechanism of action, devices, indications, techniques, potential complications, clinical outcomes, post‐ablation surveillance, and use in combination with other therapies. In the future, the role of RFA in the treatment of localized pulmonary tumors should ultimately be determined by evidence from prospective randomized controlled trials comparing sublobar resection or stereotactic body radiation therapy.

Abstract No. 688 Technical effectiveness of navigation-assisted percutaneous ablation of malignant liver tumors

Abstract No. 688 Technical effectiveness of navigation-assisted percutaneous ablation of malignant liver tumors

4:12 PM Abstract No. 179 Percutaneous Emprint™ microwave ablation of malignant liver tumours: a report of the first 100 cases

A new MWA device, the Emprint™ Microwave Ablation System, is purported to achieve spherical and predictable ablation zones. We aim to evaluate the clinical efficacy and short-term safety profile this device in the percutaneous ablation of malignant liver tumors. This is a retrospective IRB-approved study of patients who underwent percutaneous MWA with the Emprint™ device from Jan 2015 to April 2017 in our institution. Patient demographics, technical success rates, as well as 30-day mortality and morbidity were examined. The presence of residual disease or recurrence was recorded after review of contrast-enhanced CT/MRI up to 24 months post procedure. A total of 119 ablations were performed in 102 patients, with a mean tumor diameter of 1.7 (1.0 – 5.6) cm. Technical success rate was 99.2%. Residual disease rate at 6 weeks was 6.2%, while a recurrence rate of 2.7% was recorded. There was no procedural related mortality. One major complication of hemorrhage requiring angioembolization was recorded (0.8%), while minor complication rate was 17.6% (pneumothorax n = 5, small subcapsular haematoma/haemoperitoneum n = 5, over sedation n = 5, pleural effusion n = 4, transfusion reaction to platelets n = 1, bacteremia n = 1, focal portal vein thrombosis n = 1). Our study suggests that the Emprint™ MWA device is a safe device that allows a high degree of technical success with a low rate of residual disease and short-term recurrence.

3:54 PM Abstract No. 246 Intraprocedural renal hilar nerve block during percutaneous renal tumor ablation: a postoperative opioid-sparing pain management technique

3:54 PM Abstract No. 246 Intraprocedural renal hilar nerve block during percutaneous renal tumor ablation: a postoperative opioid-sparing pain management technique

3:36 PM Abstract No. 256 Percutaneous tumor ablation in patients with metastatic sarcoma stable on chemotherapy

This is a phase II study in patients with metastatic soft tissue sarcoma who had been stable on six cycles of chemotherapy and then received ablation therapy to their residual disease. Following ablation, patients were not treated with any further therapy, but were followed by surveillance imaging to determine the progression-free rate. Patients had histologically/cytologically confirmed high-grade metastatic sarcoma stable on 6-12 cycles of one chemotherapeutic regimen with lesions that could be accurately measured in at least one dimension as >10 mm on cross sectional imaging, and could have no more than 10 treatable lesions. Eligible patients had their lesions ablated using the preferred ablation modality of the operator (cryoablation and radiofrequency ablation) based on lesion location/characteristics. Chemotherapy was stopped at initiation of ablation therapy and patients were followed with CT scans every 9 weeks for the first year, every 12 weeks for the second year, and then every 6 months until a new biopsy-proven lesion or a previously ablated lesion grew by 20% in size. The primary outcome was to determine the progression-free rate at 3 months. Over three years, eight patients enrolled who were eligible for this study. Histologies included leiomyosarcoma, malignant peripheral nerve sheath tumor, myxoid liposarcomas, and pleiomorphic rhabodmyosarcoma. The patients had between 1-8 lesions on CT at the start of chemotherapy. Following chemotherapy, patients had 1-4 sites of residual disease requiring ablation. The lesions ablated included pulmonary nodules and retroperitoneal and peritoneal lesions. Despite the fact that the trial was stopped early due to low enrollment, there was a 3-month progression-free rate (PFR) of 75% and median progression-free survival (PFS) was 19.74 months. There were two major complications of pneumothoraces following lung cryoablation requiring chest tubes. This is the first prospective study of ablation therapy following stability on chemotherapy in patients with metastatic sarcoma and strongly supports ablation for local tumor control and maintenance therapy with significant PFS along with a chemotherapy-free holiday.

Percutaneous Image-Guided Treatment of Benign Musculoskeletal Tumors in Children.

Percutaneous ablation of benign musculoskeletal tumors in children has become an area of significant clinical growth over the last decade. With growing research interest, the technologies available and techniques used are becoming increasingly safe and effective. We review some of the more common ablation technologies and their utility in several common benign bone and soft tissue tumors that occur in children and young adults.

Thoracic paravertebral block for the anesthetic management of percutaneous radiofrequency ablation of liver tumors.

Background and Aims:Percutaneous radiofrequency ablation (PRFA) is a minimally invasive treatment for hepatic tumors. We assessed and compared the efficacy of right thoracic paravertebral block (TPVB) with that of local anesthetic infiltration for the anesthetic management of PRFA of liver tumors.Material and Methods:Sixty patients with hepatic tumors aged 50–80 years were randomly allocated into two groups. Group I received local anesthetic infiltration along the path of the ablation device with sedation. Group II received right TPVB at the level T7 and T9 with sedation. The pain was assessed using visual analog scale (VAS) at 1 min and then every 5 min during PRFA procedure, on admission, and discharge from the post-PRFA observation area. The total dose of rescue analgesia during PRFA procedure, number of patients requiring general anesthesia, patient and radiologist satisfaction were reported.Results:VAS was significantly lower in group II than group I during and after PRFA procedure (P < 0.05). General anesthesia was administered in 7 patients in group I, whereas no patient required general anesthesia in group II (P < 0.05). Patient and radiologist satisfaction were significantly higher in group II compared to group I (P < 0.05). There were no significant complications in group II compared to group I (P > 0.05).Conclusions:Right TPVB with sedation is an effective and safe anesthetic technique for the management of PRFA procedure of hepatic tumors. It is more effective than local anesthesia with sedation in relieving pain during PRFA procedure of hepatic tumors.

The Effectiveness of Ultrasound-Guided Thoracic Paravertebral Block for Percutaneous Radiofrequency Ablation of Hepatic Tumors: A Pilot Study

The Effectiveness of Ultrasound-Guided Thoracic Paravertebral Block for Percutaneous Radiofrequency Ablation of Hepatic Tumors: A Pilot Study

In vitro artifact assessment of an MR-compatible, microwave antenna device for percutaneous tumor ablation with fluoroscopic MRI-sequences

Objective: To evaluate artifact configuration and diameters of a magnetic resonance (MR) compatible microwave (MW) applicator using near-realtime MR-fluoroscopic sequences for percutaneous tumor ablation procedures.Material and methods: Two MW applicators (14 G and 16 G) were tested in an ex-vivo phantom at 1.5 T with two 3 D fluoroscopic sequences: T1-weighted spoiled Gradient Echo (GRE) and T1/T2-weighted Steady State Free Precession (SSFP) sequence. Applicator orientation to main magnetic field (B0), slice orientation and phase encoding direction (PED) were systematically varied. The influence of these variables was assessed with ANOVA and post-hoc testing.Results: The artifact was homogenous along the whole length of both antennas with all tested parameters. The tip artifact diameter of the 16 G antenna measured 6.9 ± 1.0 mm, the shaft artifact diameter 8.6 ± 1.2 mm and the Tip Location Error (TLE) was 1.5 ± 1.2 mm.The tip artifact diameter of the 14 G antenna measured 7.7 ± 1.2 mm, the shaft artifact diameter 9.6 ± 1.5 mm and TLE was 1.6 ± 1.2 mm. Orientation to B0 had no statistically significant influence on tip artifact diameters (16 G: p = .55; 14 G: p = .07) or TLE (16 G: p = .93; 14 G: p = .26). GRE sequences slightly overestimated the antenna length with TLE(16 G) = 2.6 ± 0.5 mm and TLE(14 G) = 2.7 ± 0.7 mm.Conclusions: The MR-compatible MW applicator’s artifact seems adequate with an acceptable TLE for safe applicator positioning during near-realtime fluoroscopic MR-guidance.

Reduced microperfusion due to portal vein thrombosis: Impact on the outcome of percutaneous thermal tumor ablation.

To determine the influence of pre-interventionally existing portal vein thrombosis on the ablation success of percutaneous tumor ablation of HCC. 15 patients with HCC and pre-existing portal vein thrombosis underwent thermal tumor ablation. We retrospectively analyzed the pre- and post-interventionally performed CT and MRI scans in terms of technical success as well as the complication rate. The portal vein thrombosis was classified into segmental, lobar and central thrombus. In 13/15 cases (87%) complete ablation with no evidence of residual tumor tissue was seen 6 weeks after the procedure in contrast-enhanced MRI scans and contrast-enhanced ultrasound (CEUS). No major and 2 minor complications were observed after the ablation procedure. Reduced perfusion due to pre-interventionally existing portal vein thrombosis has no significant impact on the ablation success or the complication rate.

Percutaneous Image-Guided Ablation in the Treatment of Osseous Metastases from Non-small Cell Lung Cancer.

Percutaneous image-guided ablation is an emerging minimally invasive therapy for patients with metastatic bone disease for whom radiation therapy is ineffective or contraindicated. The purpose of this study was to examine the safety and efficacy of percutaneous ablation in achieving pain palliation and local tumor control of osseous metastases from non-small cell lung cancer (NSCLC). A retrospective review was performed of 76 musculoskeletal metastases in 45 patients treated with percutaneous ablation. 63% (48/76) were treated with radiofrequency ablation (RFA), 35% (27/76) with cryoablation, and 1.3% (1/76) with microwave ablation (MWA). In 70% (53/76) of cases, associated cementoplasty was performed. Primary outcomes measured were pre- and post-procedure pain scores 4weeks after treatment and local tumor control at 3-, 6-, and 12-month follow-up. Mean age of the cohort was 63.6±9.5years. Median tumor diameter was 3.60cm (range 1.0-10.0cm). Mean and median pain scores before treatment were 7.5±2.3 and 8.0, respectively. Post-procedure, patients reported significantly decreased pain scores at 4weeks (mean, 3.7±3.5; median, 3.0; p<0.00001). Radiographic local tumor control rates were 83% (35/42) at 3months, 77% (23/30) at 6months, and 68% (17/25) at 12months after treatment. The overall complication rate was 2.6% (2/76). Percutaneous tumor ablation is a well-tolerated, minimally invasive procedure associated with improving pain palliation and achieving local tumor control of osseous metastases from NSCLC. Level 4, case series.

Does intra-tumoural fat on MRI predict visibility of small (≤3 cm) hepatocellular carcinomas during ultrasound-guided tumour ablation?

To assess if intra-tumoural fat on magnetic resonance imaging (MRI) affects the ultrasonographic(US) visibility of small (≤3 cm) hepatocellular carcinomas (HCC) during radiofrequency ablation (RFA). Institutional review board approval was obtained. A retrospective review of all patients who underwent image-guided ablation between 1 January 2010 and 31 April 2015 was performed. Patients with HCC who underwent US RFA were included. Inclusion criteria included small tumours (≤3 cm), treatment-naive cases or new focus of HCC in a different and untreated segment, and pre-procedural MRI. The presence of intra-tumoural fat was determined retrospectively via in-and-out-of-phase MRI. Other factors that potentially affect ultrasonographic visibility, such as background fatty liver, presence of cirrhosis, tumour size, and distance from diaphragm, were recorded. Ninety procedures performed on 74 patients (62 men and 12 women; mean age: 67.3 years; range: 39-88 years). Seventy-two tumours were visible on US (hypoechoic n=35, hyperechoic n=28, heterogeneous n=9). Intra-tumoural fat was seen in 23 tumours (25.6%, hyperechoic n=17, hypoechoic n=6). The presence of intra-tumoural fat (p=0.005) and distance from diaphragm (p=0.007) were found to be statistically significant factors affecting tumour visibility on planning US. The presence of background fatty liver (p=0.485), cirrhosis (p=0.48), and tumour size (p=0.15) were not found to be significant. The present study shows that the presence of intra-tumoural fat in small HCCs on pre-procedural MRI can accurately predict their visibility on planning US during percutaneous tumour ablation.

Percutaneous thermal ablation of lung tumors - Radiofrequency, microwave and cryotherapy: Where are we going?

Main indications of percutaneous pulmonary thermal ablation are early stage non-small cell lung carcinoma (NSCLC) for patients who are not amenable to surgery and slow-evolving localized metastatic disease, either spontaneous or following a general treatment. Radiofrequency ablation (RFA) is the most evaluated technique. This technique offers a local control rate ranging between 80 and 90% for tumors <3cm in diameter. Other more recently used ablation techniques such as microwaves and cryotherapy could overcome some limitations of RFA. One common characteristic of these techniques is an excellent tolerance with very few complications. This article reviews the differences between these techniques when applied to lung tumors, indications, results and complications. Future potential associations with immunotherapy will be discussed.

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.

Semiautomated registration of pre- and intraoperative CT for image-guided percutaneous liver tumor ablation interventions.

In CT-guided liver tumor ablation interventions, registration of a preoperative contrast-enhanced CT image to the intraoperative CT image is hypothesized to improve guidance. This is a highly challenging registration task due to differences in patient poses and large deformations, and therefore high registration errors are expected. In this study, our objective is to develop a method that enables users to locally improve the registration where the registration fails, with minimal user interaction. The method is based on a conventional nonrigid intensity-based registration framework, extended with a novel point-to-surface penalty. The point-to-surface penalty serves to improve the alignment of the liver boundary, while requiring minimal user interaction during the intervention: annotating some points on the liver surface at those regions where the conventional registration seems inaccurate. The method is evaluated on 18 clinical datasets. It improves registration accuracy compared with the conventional nonrigid registration in terms of average surface distance (from 2.75 to 2.05mm) and target registration error (from 6.92 to 5.8mm). In this study, we introduce a semiautomated registration algorithm that improves the accuracy of image registration.

Robust Real-Time Needle Tracking in 2-D Ultrasound Images Using Statistical Filtering

Percutaneous image-guided tumor ablation is a minimally invasive surgical procedure for the treatment of malignant tumors using a needle-shaped ablation probe. Automating the insertion of a needle by using a robot could increase the accuracy and decrease the execution time of the procedure. Extracting the needle tip position from the ultrasound (US) images is of paramount importance for verifying that the needle is not approaching any forbidden regions (e.g., major vessels and ribs), and could also be used as a direct feedback signal to the robot inserting the needle. A method for estimating the needle tip has previously been developed combining a modified Hough transform, image filters, and machine learning. This paper improves that method by introducing a dynamic selection of the region of interest in the US images and filtering the tracking results using either a Kalman filter or a particle filter. Experiments where a biopsy needle has been inserted into a phantom by a robot have been conducted, guided by an infrared tracking system. The proposed method has been accurately evaluated by comparing its estimations with the needle tip’s positions manually detected by a physician in the US images. The results show a significant improvement in precision and more than 85% reduction of 95th percentile of the error compared with the previous automatic approaches. The method runs in real time with a frame rate of 35.4 frames/s. The increased robustness and accuracy can make our algorithm usable in autonomous surgical systems for needle insertion.

Changes in peripheral blood T-cell balance after percutaneous tumor ablation

Purpose: To evaluate the changes in T-cell balance in peripheral blood following percutaneous tumor ablation.Material and methods: Patients underwent thermal ablation including radiofrequency (n = 9) and microwave ablation (n = 5), or cryoablation (n = 5). Target tumors were located in the lung (n = 7), soft tissue (n = 5), liver (n = 4), and bone (n = 3). Patient peripheral blood samples were collected before and within 14 days after ablation. Peripheral blood populations of cytotoxic T-cells (CTL), type-1 (Th1) and type-2 helper T-cells (Th2), and regulatory T-cells (Treg) were measured using flow cytometry. Changes in CTL/Treg and Th1/Th2 ratios before and after ablation therapy were compared using paired t-tests.Results: Peripheral blood CTL population (27.5 ± 2.1% to 30.2 ± 2.5%, p < .03) and CTL/Treg ratios (18.8 ± 3.7% to 21.6 ± 3.6%, p < .05) increased significantly after ablation. Although a significant increase in CTL/Treg ratios was found after heat-based ablation (18.0 ± 4.4% to 21.6 ± 4.7%, p < .02), it remained unchanged after cryoablation (21.0 ± 7.0% to 21.5 ± 4.3%, p = .92). Th1/Th2 ratio (13.7 ± 3.0% to 17.2 ± 3.5%, p = .12) remained unchanged after ablation.Conclusion: Ablation therapy alters the T-cell balance by increasing the systemic CTL/Treg, ratio. Heat-based ablation might be a more effective approach than cryoablation to enhance systemic anti-tumor immunity.

Risk Factors for Local Progression after Percutaneous Radiofrequency Ablation of Lung Tumors: Evaluation Based on a Review of 147 Tumors

PurposeTo retrospectively evaluate risk factors related to incomplete computed tomography (CT)–guided radiofrequency (RF) ablation of metastatic and primary lung tumors. Materials and MethodsThis study included 93 patients with 147 tumors: 70 men, 23 women; median age 54 y (range, 19–81 y); 24 cases of primary lung tumors, 69 cases of metastases; average largest diameter of tumors, 1.8 cm ± 1.2 (range, 0.3–6.0 cm). Local efficacy was evaluated based on CT follow-up scans. Complete ablation rates (CARs) for tumors were calculated according to several variables; independent risk factors for local tumor progression (LTP) were examined by binary logistic regression analysis. ResultsCAR of tumors was 60.54% within first 6 months after lung RF ablation; median interval of LTP was 1.5 months (mean, 1.3 months ± 1.0; range, 0 days to 3 months). Compared with tumors > 3 cm, CAR of tumors ≤ 3 cm was significantly higher (68.55% vs 17.39%, P < .001). CAR of tumors with complete ablation margin (AM) was dramatically higher compared with tumors with incomplete AM (74.77% vs 16.67%, P < .001). Among tumors with complete AM, CAR of tumors with shortest distance between outer edge of tumor and AM (ablative margin D) ≥ 5 mm was compared with tumors with ablative margin D 1–4 mm (85.96% vs 62.96%, P = .005). Multivariate regression analysis showed that lobulation and/or spicules, contact with blood vessels, and ablative margin D < 5 mm were independent risk factors for incomplete lung RF ablation. LTP was likely to develop at the edge of ablated lesions and especially the site of incomplete AM or shortest AM. ConclusionsRF ablation for lung cancers should be individualized based on tumor size, morphology, and tumor type to obtain an adequate AM.