Radiofrequency Ablation Of Tumors Research Articles

Endoscopic ultrasound-guided radiofrequency ablation of pancreatic tumors.

Surgery is a cornerstone in the management of pancreatic cancer and precancerous pancreatic lesions. However, many patients are not suitable candidates for surgery at the time of diagnosis for various reasons. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) appears to be a promising treatment option for patients who are ineligible for surgery for management of pancreatic adenocarcinoma (PDAC), and pancreatic neuroendocrine tumors (PNETs), and pancreatic cystic lesions (PCLs). EUS-RFA may serve as an adjunct to chemotherapy or palliative measures for inoperable cases of PDAC. Given its feasibility and efficacy, EUS-RFA has an evolving niche as a minimally invasive and potentially definitive treatment for PNETs and high-risk PCLs such as intraductal papillary mucinous neoplasms (IPMNs). EUS-RFA is a generally well tolerated procedure, with abdominal pain and acute pancreatitis being the most common adverse effects, though the risk can be mitigated through prophylactic measures. There is an increasing body of evidence to support the use of EUS-RFA in managing pancreatic lesions, either as definitive, adjunctive, or palliative treatment, depending on lesion type.

Echocardiography-Guided Radiofrequency Ablation for Cardiac Tumors

Echocardiography-Guided Radiofrequency Ablation for Cardiac Tumors

First experience of endoscopic radiofrequency ablation in tumor-induced stenosis of extrahepatic bile ducts

Aim. To evaluate technical features, safety and efficiency of radiofrequency ablation in tumor strictures of extrahepatic bile ducts. Materials and methods. An ongoing prospective observational study from September 2022 to June 2023 enrolled patients with unresectable extrahepatic bile duct tumors. Examination involved esophagogastroduodenoscopy, endoscopic ultrasound, retrograde cholangiopancreatography and video choledochoscopy with biopsy. Ductalradiofrequency ablation with polymeric or self-expanding metallic stent placement was applied as the main treatment method for the first time in Russia. Results. 3 patients (75 %) were diagnosed with cholangiocarcinoma of stage IIb–IIIa, 1 patient – with mucinous cystic tumor with signs of severe intraepithelial neoplasia. Radiofrequency ablation was successfully performed in all patients: tumor stenosis was completely eliminated, no complications reported in the immediate and distant period. The median follow-up period amounted to 8 months. Conclusion. The results of the first application of ductal radiofrequency ablation in unresectable tumors of extrahepatic bile ducts with stenosis prove to be positive. The method is considered to be effective, minimally invasive and safe.

Endoscopic radiofrequency ablation of pancreatic neuroendocrine tumors

Aim. To present the first experience of EUS-guided radiofrequency ablation in the treatment of patients with functioning neuroendocrine tumors of the pancreas. Materials and methods. Endoscopic radiofrequency ablation was performed in 2 patients with insulin-producing neuroendocrine tumor of the pancreatic head and clinical picture of organic hyperinsulinism. The radiofrequency ablation system includes a 19-gauge needle electrode to be conducted through the forceps aperture, a generator and an intraelectrode cooling system. Results. The efficacy of ultrasound-guided radiofrequency ablation in the cases presented above appears to be clinically proven. The outcomes include stabilization of the blood glucose level, a complete elimination of hypoglycemia-associated clinical symptoms. Both observations reveal no complications after the procedure. Conclusion. EUS-guided radiofrequency ablation appears to possess a potential for wider application as a minimally invasive intervention, thus introducing an alternative to surgical treatment of patients with neuroendocrine tumors of the pancreas. An experience of EUS-guided radiofrequency ablation is worth to be accumulated and outcomes of the method application to be analyzed on a larger number of clinical observations.

Risk Factors for Hospitalization Duration Longer Than 24 Hours Following Percutaneous Radiofrequency Ablation of Liver Tumours.

Prior studies have described complications of radiofrequency ablation (RFA) of liver tumours. The aim of this study was to identify risk factors for hospitalization duration longer than 24 hours following RFA of liver tumours. This retrospective, single-centre study included patients with liver tumours undergoing RFA between October 2017 and July 2020. Medical records were reviewed to collect patient, tumours, and procedure characteristics for each RFA session. The association between potential risk factors and duration of hospitalization (less than or more than 24 hours) was analyzed using univariate and multivariate logistic regressions. Our study included 291 patients (mean age: 65.2 ± 11.2 [standard deviation]; 201 men) undergoing 324 RFA sessions. Sixty-eight sessions (21.0%) resulted in hospitalization of more than 24 hours. Multivariate analysis identified each additional needle insertion per session (OR 1.4; 95% CI [1.1-1.9]; P = .02), RFA performed in segment V (OR 2.8; 95% CI [1.4-5.7]; P = .004), and use of artificial pneumothorax (OR 14.5; 95% CI [1.4-146.0]; P = .02) as potential risk factors. A history of hepatic encephalopathy (OR 2.6; 95% CI [1.1-6.0]; P = .03) was only significant in univariate analysis. Post-hoc, subgroup analysis of patients with hepatocellular carcinoma (69.8%) did not identify other risk factors. Risk factors for a hospitalization duration longer than 24 hours include a higher number of needle insertions per session, radiofrequency ablation in segment V, and use of an artificial pneumothorax.

Study on Radiofrequency Ablation of Lung and Kidney Tumors With and Without Nanoparticles Using Multi-Tined Electrode

Abstract Radio frequency ablation (RFA) is an alternative method for the cure of malign tumors in the liver, lung, and kidney. In the present work, finite element method (FEM) analysis is conducted to study the effect of nanoparticles on the temporal and spatial temperature distribution during RFA. Three-dimensional thermoelectrically FEM model consisting of a multitined radio frequency electrode (nine-tine, deployed up to 2 cm) and a cubical tumor of size 50 mm3 is developed. Numerical simulation is carried out under the temperature-controlled mode (95 °C) with 10 min ablation time. A study using multitined electrodes is carried out on different tissues, i.e., lung and kidney, with and without nanoparticles. Results show that the nanoparticles increase the heat conduction rate and decrease the ablation time up to 13% for the inclusion of 6% nanoparticles. It has been found that the spatial temperature distribution becomes uniform with nanoparticle assistance.

Mid- to long-term outcome of laparoscopic ultrasound–guided radiofrequency ablation for malignant hepatic tumors

BackgroundThis study aimed to evaluate the long-term outcomes of fully laparoscopic ultrasound–guided radiofrequency ablation (LURFA) in malignant hepatic tumors that are difficult to curatively treat with the percutaneous approach or laparoscopic liver resection (LLR). MethodsBetween 2011 and 2021, 62 patients with malignant hepatic tumors (37 hepatocellular carcinomas [HCCs] and 25 metastatic colorectal cancers [mCRCs]), who were not feasible to be curatively treated by percutaneous radiofrequency ablation or LLR, were enrolled and treated only by LURFA. Patients who underwent concurrent surgical resection were excluded. The cumulative incidence rates of local recurrence (LR) and survival were analyzed. ResultsAll 93 tumors with a median diameter of 22.0 mm (IQR, 8.0–50.0) and a median number of 1.5 tumors (IQR, 1.0–6.0) in 62 patients were successfully treated. According to the IWATE criteria for LLR, 33 of 62 patients (53.2%) had tumors in difficult locations (segments I, VII, VIII, and IVa). Over a median follow-up period of 92.4 months (IQR, 60.0–128.0), the 1-, 2-, 3-, 5-, 8-, and 10-year cumulative incidence rates of LR were 6.9%, 13.8%, 17.2%, 17.2%, 20.9%, and 20.9%, respectively. In patients with HCC, 1-, 3-, 5-, and 8-year survival rates were 97.2%, 80.6%, 55.6%, and 40.1%, respectively. In patients with mCRC, 1-, 3-, 5-, and 8-year survival rates were 100.0%, 36.4%, 27.3%, and 16.4%, respectively. Adverse events of grade 3 occurred in only 3 of 62 patients (4.8%). ConclusionFull LURFA is a safe and effective treatment for malignant hepatic tumors, even in difficult percutaneous ablation or LLR areas.

Effectiveness of integrated prophylactic antibiotics prescription in patients undergoing radiofrequency and microwave ablation of liver tumors: a retrospective cohort study

An institutionalised in-house antibiotic prophylaxis (AP) guideline was developed in May 2019 to standardize AP prescription. This retrospective cohort study evaluated the effectiveness and clinical outcomes of the newly launched AP guideline on patients undergoing radiofrequency (RFA) and microwave (MWA) ablation of the liver from November 2018 to March 2020. Patients without high risk of biliary tree contamination were recommended a single dose of 2g IV cefazolin (or 600mg IV clindamycin in cases of beta-lactam allergy). Univariate analysis was conducted to evaluate the clinical outcomes.
 
 The study included 87 patients who underwent 93 procedures consisting of 18 RFAs and 75 MWAs for liver tumours. Concordance with AP guidelines improved significantly (38.5% vs. 87.0%; p<0.001). There were no ablation-related infections and mortality within 30 days post-ablation, and post-procedural nausea and vomiting were significantly reduced (15.4% vs. 1.9%; p=0.020). No significant difference in post-procedural fever (7.7% vs. 5.6%; p-value=0.693), chest and/or abdominal pain (5.1% vs. 7.4%; p=1.000) were noted.
 
 The newly implemented in-house antibiotic prophylaxis guideline streamlined AP prescribing in patients undergoing RFA and MWA. Additional research is needed to determine the effects on infection and mortality in patients with high-risk factors such as bile duct stents, sphincterotomies, and biliary-enteric anastomoses.

Peripheral T-cell subsets in radiofrequency ablation for tumors from different origins

BackgroundsRadiofrequency ablation (RFA) is known to destroy tumoral tissue and activate immune cells. This study aimed to investigate the impact of RFA on peripheral T-cell responses and its relationship with tumor origin and hepatitis status. MethodsA retrospective analysis was conducted on 62 patients with various types of tumors, including hepatocellular carcinoma, colorectal cancer, lung cancer, breast cancer, and others, who underwent RFA treatment between June 2017 and December 2018. Blood samples were collected before and one day after RFA treatment. The peripheral T-cell subsets were measured by flow cytometry, and their changes were analyzed. ResultsThe study found a decrease in the CD4+CD8-and CD4-CD8+ T-cell subsets after RFA, but no significant changes were observed in the populations of CD4+CD8+ and the CD4+CD8-/CD4-CD8+ ratio. Furthermore, no significant differences were observed in peripheral T-cell subsets concerning tumor type or hepatitis status. ConclusionsThe study suggests that RFA treatment may have a short-term impact on peripheral T-cell responses, characterized by a decrease in certain T-cell subsets. However, these changes do not seem to be related to the tumor type or hepatitis status of the patients.

Diaphragmatic Liver Herniation after Radiofrequency Ablation of a Secondary Liver Tumor.

Radiofrequency thermal ablation (RFA) is widely used and has been accepted for the treatment of unresectable tumors. The leading technique that is used is percutaneous RFA under CT or US guidance. Multicenter surveys report acceptable morbidity and mortality rates for RFA. The mortality rate ranges from 0.1% to 0.5%, the major complication rate ranges from 2% to 3%. Diaphragmatic injury is a rare complication and it is described after RFA of subdiaphragmatic tumors. Most of them are without clinical importance. There are some case reports about diaphragmatic herniation of the intestine into the pleural cavity. We present a case of diaphragmatic perforation resulting in the herniation of the liver into the pleural cavity. A thoracotomy was performed, the liver was lowered back into the peritoneal cavity and the perforation was closed with mesh.

Complication Rates and Risk of Recurrence After Percutaneous Radiofrequency Ablation and Microwave Ablation for the Treatment of Liver Tumors: a Meta-analysis

The rate of complications and risk of local recurrence following percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) for liver tumors varies significantly between investigations. This meta-analysis aimed to assess complication rates and risk of local recurrence after percutaneous RFA and MWA. PubMed, Medline, Web of Science, the Cochrane Library, Embase, Google Scholar, and CINAHL were systematically searched from database inception until August 2022 to retrieve articles reporting the complication rates and risk of recurrence after percutaneous RFA and MWA for the treatment of liver tumors. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated and displayed by forest plots. To measure heterogeneity, Cochran Q and I2 statistics were also applied. Egger's test and funnel plots were also performed to assess any potential publication bias. Additionally, subgroup analysis was done to investigate the source of heterogeneity. 26 studies including 2026 and 1974 patients for RFA and MWA, respectively, were included. The rate of minor complications was significantly higher after MWA compared to RFA, yielding an overall OR of 0.688 (95% CI: 0.549-0.862, P = 0.001). Similarly, the rate of major complications was significantly higher after MWA than RFA (P = 0.012), yielding an overall OR of 0.639 (95% CI: 0.450-0.907). No significant difference was found between RFA and MWA in terms of local recurrence after ablation (P > 0.05). In addition, there was no statistical evidence of publication bias. When most factors are considered equally, percutaneous RFA and MWA can be considered safe modalities for the treatment of liver tumors, with RFA superior in terms of the incidence of minor and major complications.

Research and Design of High-precision Voltage Sampling Circuit for Tumor Radiofrequency Ablation Medical Instrument

Radiofrequency ablation is a minimally invasive procedure in which tiny radiofrequency electrodes are implanted into the diseased tissue under the guidance of medical imaging (X-ray imager, CT or ultrasound), and neutral electrodes are attached to the skin of the body to carry out radiofrequency ablation, which is carried out by forming a circuit through the human body to the diseased tissue. At present, RF ablation can be applied to lung tumors, liver tumors, kidney tumors and certain heart diseases. The core component of tumor RF ablation surgery equipment is RF power source, which is a fixed frequency sinusoidal AC output signal with a frequency of 400-500Khz. The detection technology of RF voltage is extremely important, which determines the accuracy of RF ablation energy output and energy control. In this paper, we use STM32 microcontroller as the core of acquisition and control, and propose a simple and practical sampling method with high accuracy. Moreover, we have realized to control the voltage measurement error below 1% by using the error curve fitting method for software calibration.

Feasibility of the chick chorioallantoic membrane model for preclinical studies on tumor radiofrequency ablation

BackgroundWe evaluated the feasibility of a chick chorioallantoic membrane (CAM) tumor model for preclinical research on tumor radiofrequency ablation (RFA).MethodsFertilized chicken eggs were incubated and divided into five cohorts: RFA for 30 s (n = 5), RFA for 60 s (n = 5), RFA for 120 s (n = 4), sham (n = 8), and controls (n = 6). Xenografting using pancreatic neuroendocrine tumor cells of the BON-1 cell line was performed on embryonic day (ED) 8. The RFA was performed on ED 12. Survival, stereomicroscopic observations, and histological observations using hematoxylin–eosin (H&E) and Ki67 staining were evaluated.ResultsThe survival rates in the 30-s, 60-s, and 120-s, sham and control cohort were 60%, 60%, 0%, 100%, and 50%, respectively. Signs of bleeding and heat damage were common findings in the evaluation of stereomicroscopic observations. Histological examination could be performed in all but one embryo. Heat damage, bleeding, thrombosis, and leukocyte infiltration and hyperemia were regular findings in H&E-stained cuts. A complete absence of Ki67 staining was recorded in 33.3% and 50% of embryos in the 30-s and 60-s cohorts that survived until ED 14, respectively.ConclusionsThe CAM model is a feasible and suiting research model for tumor RFA with many advantages over other animal models. It offers the opportunity to conduct in vivo research under standardized conditions. Further studies are needed to optimize this model for tumor ablations in order to explore promising but unrefined strategies like the combination of RFA and immunotherapy.Relevance statementThe chick chorioallantoic membrane model allows in vivo research on tumor radiofrequency ablation under standardized conditions that may enable enhanced understanding on combined therapies while ensuring animal welfare in concordance with the “Three Rs.”Key points• The chorioallantoic membrane model is feasible and suiting for tumor radiofrequency ablation.• Radiofrequency ablation regularly achieved reduction but not eradication of Ki67 staining.• Histological evaluation showed findings comparable to changes in humans after RFA.• The chorioallantoic membrane model can enable studies on combined therapies after optimization.Graphical

P55. Radiofrequency ablation and vertebral augmentation for spinal metastatic tumors: a systematic review and meta-analysis of safety and treatment outcomes

P55. Radiofrequency ablation and vertebral augmentation for spinal metastatic tumors: a systematic review and meta-analysis of safety and treatment outcomes

High-security automatic path planning of radiofrequency ablation for liver tumors

Background and objectiveRadiofrequency ablation (RFA) is an effective method for the treatment of liver tumors. Preoperative path planning, which plays a crucial role in RFA treatment, requires doctors to have significant experience and ability. Specifically, correct and highly active preoperative path planning should ensure the safety of the whole puncturing process, complete ablation of tumors and minimal damage to healthy tissues. MethodsIn this paper, a high-security automatic multiple puncture path planning method for liver tumors is proposed, in which the optimization of the ablation number, puncture number, target positions and puncture point positions subject to comprehensive clinical constraints are studied. In particular, both the safety of the puncture path and the distribution of ablation ellipsoids are taken into consideration.The influence of each constraint on the safety of the whole puncturing process is discussed in detail. On this basis, the efficiency of the planning method is obviously improved by simplifying the computational data and optimized variables. In addition, the performance and adaptability of the proposed method to large and small tumors are compared and summarized. ResultsThe proposed method is evaluated on 10 liver tumors of various geometric characteristics from 7 cases. The test results show that the average path planning time and average ablation efficiency are 41.4 s and 60.19%, respectively. For tumors of different sizes, the planning results obtained from the proposed method have similar healthy tissue coverage. Through the clinical evaluation of doctors, the planning results meet the needs of RFA for liver tumors. ConclusionsThe proposed method can provide reasonable puncture paths in RFA planning, which is beneficial to ensure the safety and efficiency of liver tumor ablation.

A Safety and Feasibility Trial of Ultrasound-Guided Radiofrequency Ablation of Parotid Warthin's Tumor.

To determine if ultrasound-guided (USG) radiofrequency ablation (RFA) of Parotid Warthin's tumor under local anesthesia is a safe and effective procedure. Safety and feasibility study. Tertiary academic medical center. This is an IDEAL phase 2a trial in a tertiary referral center. Twenty patients with Parotid Warthin's tumor were recruited. RFA was done between September and December 2021 for all 20 patients using a CoATherm AK-F200 machine with a disposable, 18G × 7 mm radiofrequency electrode. Results and follow-up statistics were compared with a historic sample of patients with parotid Warthin's tumor who underwent parotidectomy between 2019 and 2021 in the same center. Nineteen patients were included in the analysis as 1 patient dropped out after 4 weeks of follow-up. The mean age for the RFA group was 67 years old with most of them being male smokers. At a median of 45 weeks (44-47 weeks) postprocedure there was a 7.48 mL (68.4%) volume reduction compared to baseline. Three patients had transient facial nerve (FN) paresis, 1 recovered within hours, and the other 2 by 12 weeks follow-up. Three patients had great auricular nerve numbness; 1 patient had infected hematoma treated in an out-patient manner. Compared to a historic cohort of parotidectomy patients for Warthin's tumor, there was no significant difference in FN paresis and other minor complications between the 2 treatment modalities. The current analysis suggests that USG RFAof Warthin's Tumor is a safe alternative to parotidectomy with shorter operative time and length of stay.

Selection of kilovolt based on body mass index reduced radiation dose for computed tomography-guided radiofrequency ablation of liver tumors

Selection of kilovolt based on body mass index reduced radiation dose for computed tomography-guided radiofrequency ablation of liver tumors

Flexible Needle Steering with Tethered and Untethered Actuation: Current States, Targeting Errors, Challenges and Opportunities

Accurate needle targeting is critical for many clinical procedures, such as transcutaneous biopsy or radiofrequency ablation of tumors. However, targeting errors may arise, limiting the widespread adoption of these procedures. Advances in flexible needle (FN) steering are emerging to mitigate these errors. This review summarizes the state-of-the-art developments of FNs and addresses possible targeting errors that can be overcome with steering actuation techniques. FN steering techniques can be classified as passive and active. Passive steering directly results from the needle-tissue interaction forces, whereas active steering requires additional forces to be applied at the needle tip, which enhances needle steerability. Therefore, the corresponding targeting errors of most passive FNs and active FNs are between 1 and 2mm, and less than 1mm, respectively. However, the diameters of active FNs range from 1.42 to 12mm, which is larger than the passive steering needle varying from 0.5 to 1.4mm. Therefore, the development of active FNs is an area of active research. These active FNs can be steered using tethered internal direct actuation or untethered external actuation. Examples of tethered internal direct actuation include tendon-driven, longitudinal segment transmission and concentric tube transmission. Tendon-driven FNs have various structures, and longitudinal segment transmission needles could be adapted to reduce tissue damage. Additionally, concentric tube needles have immediate advantages and clinical applications in natural orifice surgery. Magnetic actuation enables active FN steering with untethered external actuation and facilitates miniaturization. The challenges faced in the fabrication, sensing, and actuation methods of FN are analyzed. Finally, bio-inspired FNs may offer solutions to address the challenges faced in FN active steering mechanisms.

Highlighting the effect of heterogeneous blood perfusion on radio-frequency ablation of human brain tumors: An image-based numerical investigation

Radio-frequency ablation (RFA) is a minimally invasive treatment that can provide highly localized and precise cancer therapy. Despite these advantages, its application in clinical practice remains limited. This is primarily due to the insufficient ablation volume, where blood perfusion plays a significant role. In this study, computational modeling is applied to examine the effects of heterogeneous blood perfusion on the tissue temperature, resultant thermal damage, and ablation volume in the RFA treatment. Two patients' heterogeneous blood perfusion and 3D brain tumor geometry are extracted from their dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) data. This patient-specific information is imported into the bioheat transfer model developed in OpenFOAM to predict thermal effects. Results show that the heterogeneous blood perfusion leads to deeper heat penetration in the tumor tissue compared to the simulation in which blood perfusion is assumed to be uniform across the entire tumor. On average, the predicted tissue temperature and ablation volume are 10–11% and 30–38% higher for both patients, respectively, when the heterogeneous blood perfusion is adopted. In addition, the ablation volume is highly susceptible to the applied RF voltage and coolant temperature. These two factors can be optimized to maximize the treatment. However, the optimal settings vary for each patient, highlighting the demand for patient-specific design. Results obtained from this study can assist clinicians and surgeons in optimizing RFA parameters for a specific patient that can improve the treatment efficacy.

Abstract No. 548 Mid- to Long-Term Outcome of Laparoscopic Ultrasound-Guided Radiofrequency Ablation for Malignant Hepatic Tumors

Abstract No. 548 Mid- to Long-Term Outcome of Laparoscopic Ultrasound-Guided Radiofrequency Ablation for Malignant Hepatic Tumors