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Background: Neuroendocrine tumors (NET) constitute a heterogeneous group of malignancies whose incidence has been on the rise over the past two decades, currently documented at 5.25 per 100,000. Liver metastasis develops in over 60% of NET patients. Even after resection recurrence rates are high, underscoring the importance of parenchymal-sparing interventions. In this study, we conducted 105 surgical microwave ablations and examined outcomes related to survival and local recurrence. Methods: Retrospective review of patients who underwent a surgical microwave ablation (MWA) at a single-center, high-volume institution from September 2007 through December 2022 using a prospective database. Primary outcome was overall survival. Results: A total of 105 operations were performed on 94 patients, with 397 tumors undergoing MWA. Median tumor size was 1.3 cm (range 0.3–8.0), and the median number of tumors ablated was 2 (range 1–12). Laparoscopic approach was utilized 69.5% of the time. The most common concomitant procedure performed was hepatectomy (33.3%) and cholecystectomy (23.8%). Clavien–Dindo grade III or IV complications occurred in 9 patients (9.6%). Mortality within 30 days occurred in 1 patient (1.1%). The rate of incomplete ablation was 0.3% per tumor. Local recurrence occurred in 2.8% of tumors. Median OS was 9.43 years [95% CI 4.23–14.63 years], with a 5- and 10-year survival probability of 70.2% and 48.2%, respectively. Conclusion: Surgical MWA offers an efficacious, parenchymal-sparing treatment of hepatic metastasis of NET, with low rates of incomplete ablation and local recurrence per tumor. [ABSTRACT FROM AUTHOR]

Background and purpose: Thermochromic gel phantoms provide a controlled medium for visual assessment of thermal ablation device performance. However, there are limited studies reporting on the comparative assessment of ablation profiles assessed in thermochromic gel phantoms against those in ex vivo tissue. The objective of this study was to compare microwave ablation zones in a thermochromic tissue‐mimicking gel phantom and ex vivo bovine liver and to report on measurements of the temperature‐dependent dielectric and thermal properties of the phantom. Methods: Thermochromic polyacrylamide phantoms were fabricated following a previously reported protocol. Phantom samples were heated to temperatures in the range of 20°C–90°C in a temperature‐controlled water bath, and colorimetric analysis of images of the phantom taken after heating was used to develop a calibration between color changes and the temperature to which the phantom was heated. Using a custom, 2.45 GHz water‐cooled microwave ablation antenna, ablations were performed in fresh ex vivo liver and phantoms using 65 W applied for 5 min or 10 min (n = 3 samples in each medium for each power/time combination). Broadband (500 MHz–6 GHz) temperature‐dependent dielectric and thermal properties of the phantom were measured over the temperature range of 22°C–100°C. Results: Colorimetric analysis showed that the sharp change in gel phantom color commences at a temperature of 57°C. Short and long axes of the ablation zone in the phantom (as assessed by the 57°C isotherm) for 65 W, 5 min ablations were aligned with the extents of the ablation zone observed in ex vivo bovine liver. However, for the 65 W, 10 min setting, ablations in the phantom were on average 23.7% smaller in the short axis and 7.4 % smaller in the long axis than those observed in ex vivo liver. Measurements of the temperature‐dependent relative permittivity, thermal conductivity, and volumetric heat capacity of the phantom largely followed similar trends to published values for ex vivo liver tissue. Conclusion: Thermochromic tissue‐mimicking phantoms provides a controlled, and reproducible medium for comparative assessment of microwave ablation devices and energy delivery settings. However, ablation zone size and shapes in the thermochromic phantom do not accurately represent ablation sizes and shapes observed in ex vivo liver tissue for high energy delivery treatments (65 W, 10 min). One cause for this limitation is the difference in temperature‐dependent thermal and dielectric properties of the thermochromic phantom compared to ex vivo bovine liver tissue, as reported in the present study. [ABSTRACT FROM AUTHOR]

Objective: Microwave lung ablation (MWA) is a minimally invasive and inexpensive alternative cancer treatment for patients who are not candidates for surgery/radiotherapy. However, a major challenge for MWA is its relatively high tumor recurrence rates, due to incomplete treatment as a result of inaccurate planning. We introduce a patient-specific, deep-learning model to accurately predict post-treatment ablation zones to aid planning and enable effective treatments. Materials and methods: Our IRB-approved retrospective study consisted of ablations with a single applicator/burn/vendor between 01/2015 and 01/2019. The input data included pre-procedure computerized tomography (CT), ablation power/time, and applicator position. The ground truth ablation zone was segmented from follow-up CT post-treatment. Novel deformable image registration optimized for ablation scans and an applicator-centric co-ordinate system for data analysis were applied. Our prediction model was based on the U-net architecture. The registrations were evaluated using target registration error (TRE) and predictions using Bland-Altman plots, Dice co-efficient, precision, and recall, compared against the applicator vendor's estimates. Results: The data included 113 unique ablations from 72 patients (median age 57, interquartile range (IQR) (49–67); 41 women). We obtained a TRE ≤ 2 mm on 52 ablations. Our prediction had no bias from ground truth ablation volumes (p = 0.169) unlike the vendor's estimate (p < 0.001) and had smaller limits of agreement (p < 0.001). An 11% improvement was achieved in the Dice score. The ability to account for patient-specific in-vivo anatomical effects due to vessels, chest wall, heart, lung boundaries, and fissures was shown. Conclusions: We demonstrated a patient-specific deep-learning model to predict the ablation treatment effect prior to the procedure, with the potential for improved planning, achieving complete treatments, and reduce tumor recurrence. Clinical relevance statement: Our method addresses the current lack of reliable tools to estimate ablation extents, required for ensuring successful ablation treatments. The potential clinical implications include improved treatment planning, ensuring complete treatments, and reducing tumor recurrence. Key Points: Reliable tools to predict the extent of ablation treatments are currently lacking. Our novel patient-specific deep-learning algorithm was shown to predict ablation zones with higher accuracy and less bias compared to the currently used estimates provided by applicator vendor. Our method for ablation prediction allows for real-time clinical deployment, with potential for improved treatment planning and reduced tumor recurrence. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the efficacy and safety of ultrasound (US)-guided microwave ablation (MWA) without artificial ascites (AA) inpatients with sub-cardiac (SC) liver cancers. Methods: This retrospective study included patients with the left lobe and caudate lobe of the liver cancer who underwent US-guided MWA in our institute from January 2020 to December 2022. According to whether the target lesion was located ≤5 mm from the pericardium, patients were divided into the SC group and the non-sub-cardiac (NSC) group. In the SC group, AA was not employed during the ablation procedure. The results of technical success, technical efficiency, local tumour progression (LTP), and major complications were recorded. Results: A total of 79 patients with 87 lesions were enrolled. There were 38 patients with 38 lesions in the SC group and 41 patients with 49 lesions in the NSC group. The median follow-up of all patients was 15 (range, 3-44) months. There was no significant difference in technical success rates (100% vs 100%), technique efficiency rates (100% vs 95.7%), LTP rates (2.63% vs 0%,), and major complication rates (2.63% vs 7.32%) between the SC group and the NSC group (P > .05). No cardiac-related complications occurred. Conclusions: US-guided MWA without AA for SC liver cancers was safe and effective. Advances in knowledge: The clinical prognosis of thermal ablation without AA in the treatment of SC liver cancers is still unclear. The finding of this study provided evidence supporting the efficacy and safety of US-guided MWA without AA for treating this tricky location. [ABSTRACT FROM AUTHOR]

Primary lung cancer is the leading cause of cancer‐related death worldwide. Recent statistics estimate 1.8 million new cases and 1.6 million deaths per year. Despite significant advances in surgery, chemotherapy, and radiotherapy, the 5‐year survival rate remains at just 18%. Thermal ablation is an established treatment that is safe and effective. It refers to the local application of controlled heat to induce irreversible cell injury and ultimately tumor apoptosis and necrosis. This approach is particularly suitable for the treatment of small tumors in patients who are not suitable for surgery. However, the lack of suitable benchtop models to assess ablation devices complicates prognostic prediction and the development of effective treatment strategies. In this context, the development of a 3D lung tumor model is presented using a cancer cell‐laden hydrogel composed of 2% hyaluronic acid–tyramine (HA‐TA) and 0.5% agarose, resulting in a tumor mimetic of clinically relevant size. This innovative model provides a valuable platform for testing ablation devices and provides insights that can significantly improve prognostic ability and refine treatment approaches for lung cancer patients. [ABSTRACT FROM AUTHOR]

Purpose: The major limitation of tumor microwave ablation (MWA) operation is the lack of predictability of the ablation zone before surgery. Operators rely on their individual experience to select a treatment plan, which is prone to either inadequate or excessive ablation. This paper aims to establish an ablation prediction model that guides MWA tumor surgical planning. Methods: An MWA process was first simulated by incorporating electromagnetic radiation equations, thermal equations, and optimized biological tissue parameters (dynamic dielectric and thermophysical parameters). The temperature distributions (the short/long diameters, and the total volume of the ablation zone) were then generated and verified by 60 cases ex vivo porcine liver experiments. Subsequently, a series of data were obtained from the simulated temperature distributions and to further fit the novel ablation coagulated area prediction model (ACAPM), thus rendering the ablation-dose table for the guiding surgical plan. The MWA clinical patient data and clinical devices suggested data were used to validate the accuracy and practicability of the established predicted model. Results: The 60 cases ex vivo porcine liver experiments demonstrated the accuracy of the simulated temperature distributions. Compared to traditional simulation methods, our approach reduces the long-diameter error of the ablation zone from 1.1cm to 0.29cm, achieving a 74% reduction in error. Further, the clinical data including the patients’ operation results and devices provided values were consistent well with our predicated data, indicating the great potential of ACAPM to assist preoperative planning. [ABSTRACT FROM AUTHOR]

Objectives Methods Results Conclusions This study aimed to identify the risk factors for lung parenchyma hemorrhage and hemoptysis during computed tomography‐guided microwave ablation (MWA) in patients with stage I non‐small cell lung cancer (NSCLC).A total of 417 patients from two medical centers were included, of whom 353 were from center 1 and 64 were from center 2. The risk factors for lung parenchyma hemorrhage and hemoptysis were selected by univariable and multivariable logistic analyses in the center 1 dataset. The selected risk factors were validated in the center 2 dataset.The risk factors for lung parenchyma hemorrhage during MWA were focal blood supplies (odds ratio [OR], 2.602; 95% confidence interval [CI], 1.609–4.210; p < 0.001), near vessels larger than 2 mm (OR, 4.145; 95% CI, 1.963–8.755; p < 0.001), and traversing vessels in the track of ablation (OR, 2.961; 95% CI, 1.492–5.874; p = 0.002). The risk factors for hemoptysis were lung parenchyma hemorrhage (OR, 34.165; 95% CI, 12.255–95.247; p < 0.001), needle track traversing the lung parenchyma by >25 mm (OR, 4.494; 95% CI, 1.833–11.018; p = 0.001), and traversing vessels in the track of ablation (OR, 5.402; 95% CI, 2.269–12.865; p < 0.001).Focal blood supplies, near vessels larger than 2 mm, and traversing vessels in the track of ablation were independent risk factors for lung parenchyma hemorrhage during MWA. Lung parenchyma hemorrhage, needle track traversing the lung parenchyma by >25 mm, and traversing vessels in the track of ablation were independent risk factors for hemoptysis during MWA. [ABSTRACT FROM AUTHOR]

Background/Objectives: Microwave ablation (MWA) is the leading therapy method for treating patients with liver cancer. MWA simulation is used to further improve the therapy and to help develop new devices. Methods: A water-cooled ablation needle was reconstructed. MWA simulations of a polyacrylamide phantom were carried out and compared with a representative clinical example (tumor diameter: 8.75 mm). The Arrhenius damage model and a critical temperature approach of 60 °C were applied to assess the necrosis zones. Finally, the simulation results were compared to the corresponding MR measurements. Results: Most of the heating in the simulation took place at a distance of 5 mm along the transverse axis and 20 mm along the longitudinal axis above the needle tip. The calculated Dice scores for the Arrhenius model were 0.77/0.53 for the phantom/clinical case. For the critical temperature approach, Dice scores of 0.60/0.66 for the phantom/clinical case were achieved. Conclusions: The comparison between simulated and measured temperature increases showed an excellent agreement. However, differences in the predicted necrosis volume might be caused by omitting consideration of the heat sink effect, especially in the clinical case. Nevertheless, this workflow enables short MWA simulation times (approximately 3 min) and demonstrates a step towards possible integration into daily clinical use. [ABSTRACT FROM AUTHOR]

Background: Ablation is an effective, parenchymal-sparing treatment for primary liver cancer and liver metastases. The purpose of this study was to report our initial experience with laparoscopic microwave ablation regarding postoperative complications, rate of conversions to open procedure, and technical efficacy. Methods: This was a quality improvement project carried out at a tertiary care center in Denmark. Patients ≥ 18 years old with liver malignancies, not available for percutaneous ablation, and treated with ultrasound-guided laparoscopic ablation were included. Results: From March 2023 to December 2023, 39 patients were referred for laparoscopic ablation after a multidisciplinary team conference. Of these, two procedures were converted to open procedures due to adhesion and tumor progression. Three patients rejected the sharing of medical information, two procedures were canceled and in one case the strategy was changed perioperatively. Therefore, 32 procedures in 31 patients were available for analysis. Complete ablation was evaluated after 1 month and was achieved in 100% of the procedures. None of the patients died, and no complications were reported in 21 cases (65.6%). Most patients with complications had a grade 1 complication based on the Clavien–Dindo classification, which among others included abdominal and shoulder pain, atrial fibrillation, and subcutaneous hematoma. Two patients had a complication grade 2 (wound infection and decompensated cirrhosis) and one had a grade 4b (sepsis due to pneumonia and urinary tract infection). The median Comprehensive Complication Index was 12.2 (interquartile range 8.7–24.2). Furthermore, univariable logistic regression showed that ≥ 2 tumors treated were associated with a higher risk of complications (odds ratio 6.37, 95% confidence interval [1.20;33.85], p-value = 0.0297). Conclusion: Ultrasound-guided laparoscopic microwave ablation of liver malignancies is feasible and safe with little risk for complications, a high technical efficacy, and a low rate of conversions to open procedures. [ABSTRACT FROM AUTHOR]

Background: To evaluate the safety and efficacy of percutaneous biopsy and microwave ablation (B + MWA) in patients with pulmonary nodules (PNs) who are receiving antithrombotic therapy by rivaroxaban as bridging therapy. Methods: The study comprised 187 patients with PNs who underwent 187 B + MWA sessions from January 1, 2020, to December 31, 2021. The enrolled patients were divided into two groups: Group A, who received antithrombotic therapy five days before the procedure and received rivaroxaban as a bridging drug during hospitalization, and group B, who had no antithrombotic treatment. Information about the technical success rate, positive biopsy rate, complete ablative rate, and major complications were collected and analyzed. Results: Group A comprised 53 patients and group B comprised 134 patients. The technical success rate was 100% in both groups. The positive biopsy rates were 88.68% and 91.04%, respectively (p = 0.6211, X2 = 0.2443). In groups A and B, the complete ablative rates at 6, 12, and 24 months were 100.0% versus 99.25%, 96.23% versus 96.27%, and 88.68% versus 89.55%, respectively. There were no significant differences in bleeding and thrombotic complications between the two groups. No grade 5 complications occurred. Conclusions: It is generally considered safe and effective that patients who are on antithrombotic therapy by rivaroxaban as bridging to undergo B + MWA for treating PNs. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to compare the combination therapy of transarterial chemoembolization (TACE) and microwave ablation (MWA) with MWA alone in treating liver metastases from colorectal cancer (LMCRC). Materials and methods: In this retrospective study, a total of 251 patients with unresectable and not to chemotherapy responding LMCRC were included. Group A consisted of 184 patients (104 male and 80 females; mean age: 64 ± 11.4 years) with 442 metastases who received a combination of TACE and MWA. A total of 67 patients (49 male and 18 females; mean age: 63.2 ± 11.8 years) with 173 metastases patients were included in group B, who received only MWA. Parameters assessed were local tumor progression (LTP), hepatic distant tumor progression (hDTP), hepatic progression-free survival (hPFS), and overall survival (OS). Results: The rate of LTP was 4.9% in group A and 4.5% in group B (p-value: 0.062). The rate of hDTP was 71.7% and 83.6% for groups A and B (p-value: 0.81), respectively. The mean hPFS was 13.8 months (95% CI 10.9–16.8) for group A and 8.1 months (95% CI 6.1–10.1) for group B (p-value: 0.03). The median OS time for group A was 30 months (95% CI 26–34), with 1-, 2-, 3-, and 4-year OS rates of 84.2%, 61.1%, 40.8% and 31.3%, respectively. In group B however, the median OS time was 26 months (95% CI 18–34) with 1-, 2-, 3-, and 4-year OS rates of 82.3%, 53.2%, 34.6% and 28.2%, respectively (p-value: 0.67). Conclusion: The combination therapy of TACE and MWA is superior to the monotherapy of MWA for LMCRC, especially regarding hDTP, hPFS and OS. [ABSTRACT FROM AUTHOR]

Purpose: Investigating the performance of the new Dophi™ M150E Microwave Ablation System, in terms of temperature distribution, ablation size and shape, reproducibility. Materials and Methods: The Dophi™ M150E Microwave Ablation System was tested on ex vivo liver, lung and kidney, at 6 different settings of time, power and number of MW antennas (single antenna: 50 and 100 W at 5 and 10 min; double antenna: 75 W at 5 and 10 min). The temperature distribution was recorded by Fiber Bragg Grating sensors, placed at different distances from the antennas. The ablation axes were measured and the sphericity index was calculated. Results: The standard deviation of ablation axes was < 5 mm, except at the highest energy and time setting for the lung. A maximum temperature rise of ~ 80 °C was measured. The measured ablation axes are overall comparable with the manufacture's values, especially at lower power and with one MW antenna (average maximum difference is 7 mm). The mean sphericity index of 0.95, 0.79 and 0.9 was obtained for the liver, lung and kidney, respectively, with a single antenna. With double antenna setup, the sphericity index was closer to 1 when 75 W for 10 min were used. Conclusions: Dophi™ M150E allows good reproducibility of ablation axes for all cases except in the lung at the highest energy level. With one antenna, an almost spherical ablation area for the liver and kidney was obtained. Using double antenna results in more homogeneous temperature distribution within the tissue compared to single antenna. [ABSTRACT FROM AUTHOR]

Twin reversed arterial perfusion (TRAP) sequence carries a high mortality risk to the "pump twin." Management involves disrupting blood flow to the acardiac mass. In this case, the pregnant patient presented at 20 weeks 6 days with Stage IIb TRAP Sequence and underwent percutaneous ultrasound‐guided microwave ablation (MWA) of the acardiac mass at 21 weeks 0 days. The probe traversed the thorax of the acardiac mass and ablated the confluence of the umbilical vessels. A healthy child was delivered at 33 weeks 5 days gestation. This report demonstrates the utility of MWA in TRAP sequence and describes a novel approach. [ABSTRACT FROM AUTHOR]

Drawing inspiration from recent advances in microwave ablation (MWA) induced in situ tumor vaccination, a colloidal hydrogel comprising amphoteric gelatin nanoparticles and poly (acrylic acid) (PAA)‐calcium carbonate nanorods (PAA‐CaCO3 NRs) is developed to deliver the microwave‐sensitive agent sodium fluoride (NaF) which can also act as a glycolysis inhibitor in conjunction with the blockade of the T‐cell Ig and ITIM domain (TIGIT), a coinhibitory receptor expressed by both natural killer (NK) cells and T cells. The combination of NaF with microwave (MW) thermal‐dynamic sensitization effectively reversed the acidic and immunosuppressive tumor microenvironment (TME). Moreover, the incorporation of anti‐TIGIT monoclonal antibody (aTIGIT) molecules amplified both the innate and adaptive immune responses by counteracting the exhaustion of NK and effective CD8+ T cells. This augmentation resulted in enhanced tumor elimination and suppression of tumor metastasis and recurrence. Thus, this study underscores the potential of colloidal hydrogel‐sensitized MWA therapy, in conjunction with aTIGIT treatments, as a promising clinical strategy for in situ cancer vaccination. [ABSTRACT FROM AUTHOR]

Background Purpose Methods Results Conclusion Microwave ablation (MWA) is a minimally invasive alternative for the treatment of unresectable liver tumors. To verify the effectiveness and safety of MWA, it is critical to measure the temperature variation and assess the regions of the microwave‐induced thermal lesions.Recent studies have indicated that the locations of optimally matched Gabor atoms (LOMGA) from ultrasound radiofrequency (RF) echo signals allow accurate and stable scatterer spacing estimation. Herein, a harmonic‐based LOMGA method is proposed to estimate the scatterer spacing for improving the assessment of microwave‐induced thermal lesions.The mean scatterer spacing (MSS) is estimated via the LOMGA method incorporating the selection of concise atoms from separated second‐harmonic RF echo signals with the pulse‐inversion algorithm for thermal lesion evaluation. In vitro experiments, 10 fresh porcine liver samples were ablated at different time nodes during the ablation period, and 200 sets of second‐harmonic and fundamental RF echo signals were randomly selected from the regions of interest in the coagulated liver samples for MSS estimation. The means and standard deviations of the MSSs, as well as the linear regression for the mean MSSs, were calculated from fundamental and second‐harmonic signals for comparison and evaluation, the receiver operating characteristic (ROC) curves for the 200 sets of fundamental‐based and harmonic‐based MSS estimates from the 10 liver samples at five pairs of adjacent time nodes were calculated, and one‐way analysis of variance (ANOVA) tests were performed for the five pairs of adjacent time nodes. The fundamental and harmonic‐based p‐values in the ANOVA tests and the areas under the ROC curves (AUCs) were calculated to statistically analyze the differences in the MSSs between adjacent time nodes.The harmonic‐based increments in the intensity variation and coherent components were larger than the fundamental‐based increments with the increasing ablation time. The harmonic‐based MSSs from the 10 liver samples at five pairs of adjacent time nodes were found to be highly statistically significant (p < 0.01). Thus, the harmonic‐based MSSs had greater variations. Compared with the fundamental‐based results, for the five preset ST values, the average increment in the harmonic‐based mean slopes was 69.22% and the average decrement in the mean standard deviations was 11.67% for the linear‐fitting MSS results, and the results were statistically significant (p < 0.05).Harmonic‐based MSSs are more sensitive and robust to variations in coagulated tissues, which is advantageous for the assessment of microwave‐induced thermal lesions. [ABSTRACT FROM AUTHOR]

Objective Patients and Methods Results Conclusion To conduct a comprehensive comparison of microwave ablation (MWA) vs radiofrequency ablation (RFA) outcomes in the treatment of small renal masses (SRMs), specifically: TRIFECTA ([i] complete ablation, [ii] absence of Clavien–Dindo Grade ≥III complications, and [iii] absence of ≥30% decrease in estimated glomerular filtration rate) achievement, operative time (OT), and local recurrence rate (LRR).We retrospectively analysed 531 patients with SRMs (clinical T1a–b) treated with MWA or RFA at a single centre (2008–2022). First, multivariable logistic regression models were used for testing TRIFECTA achievement. Second, multivariable Poisson regression models were used to evaluate variables associated with longer OT. Finally, Kaplan–Meier plots depicted LRR over time. All analyses were repeated after 1:1 propensity score matching (PSM).Of 531 patients with SRMs, 373/531 (70.2%) underwent MWA and 158/531 (29.8%) RFA. MWA demonstrated superior TRIFECTA achievement (314/373 [84.2%]) compared to RFA (114/158 [72.2%], P = 0.001). These differences were driven by higher rates of complete ablation in MWA‐ vs RFA‐treated patients (348/373 [93.3%] vs 137/158 [86.7%], P < 0.001). In multivariable logistic regression models, MWA was associated with higher TRIFECTA achievement, compared to RFA, before (odds ratio [OR] 1.92, P = 0.008) and after PSM (OR 1.99, P = 0.023). Finally, the median OT was shorter for MWA vs RFA (105 vs 115 min; P = 0.002). At Poisson regression analyses, MWA predicted shorter OT before (incidence rate ratio [IRR] 0.86, P < 0.001) and after PSM (IRR 0.85, P < 0.001). Local recurrence occurred in 17/373 (4.6%) MWA‐treated patients and 21/158 (13.3%) RFA‐treated patients (P = 0.29) after a median (interquartile range) follow‐up of 24 (8–46) months. There were no differences in the LRR in Kaplan–Meier plots before (P = 0.29) and after PSM (P = 0.42).Microwave ablation provides higher TRIFECTA achievement, and shorter OT than RFA. No significant differences were found regarding the LRR. [ABSTRACT FROM AUTHOR]

Objective: To compare therapeutic outcomes of predicted proliferative and nonproliferative hepatocellular carcinoma (HCC) after microwave ablation (MWA) using a previously developed imaging-based predictive model, the SMARS score. Methods: This multicenter retrospective study included consecutive 635 patients with unresectable HCC who underwent MWA between August 2013 and September 2020. Patients were stratified into predicted proliferative and nonproliferative phenotypes according to the SMARS score. Overall survival (OS) and recurrence-free survival (RFS) were compared between the predicted proliferative and nonproliferative HCCs before and after propensity score matching (PSM). OS and RFS were also compared between the two groups in subgroups of tumor size smaller than 30 mm and tumor size 30–50 mm. Results: The SMARS score classified 127 and 508 patients into predicted proliferative and nonproliferative HCCs, respectively. The predicted proliferative HCCs exhibited worse RFS but equivalent OS when compared with nonproliferative HCCs before (p < 0.001 for RFS; p = 0.166 for OS) and after (p < 0.001 for RFS; p = 0.456 for OS) matching. Regarding subgroups of tumor size smaller than 30 mm (p = 0.098) and tumor size 30–50 mm (p = 0.680), the OSs were similar between the two groups. However, predicted proliferative HCCs had worse RFS compared to nonproliferative HCCs in the subgroup of tumor size 30–50 mm (p < 0.001), while the RFS did not differ in the subgroup of tumor size smaller than 30 mm (p = 0.141). Conclusion: Predicted proliferative HCCs have worse RFS than nonproliferative ones after MWA, especially in tumor size larger than 30 mm. However, the phenotype of the tumor may not affect the OS. Critical relevance statement: Before performing microwave ablation for hepatocellular carcinoma, the tumor phenotype should be considered because it may affect the therapeutic outcome. Key Points: Proliferative hepatocellular carcinoma (HCC) may be identified using the SMARS score, an imaging-based predictive model. SMARS predicted proliferative HCCs have worse recurrence-free and equivalent overall survival compared to nonproliferative HCC after microwave ablation. Tumor phenotype should be considered before performing microwave ablation. [ABSTRACT FROM AUTHOR]

Purpose: To explore the plasma proteomic changes of rabbit lung VX2 tumors treated by microwave ablation, and to explore the molecular pathway mechanisms that may be involved. Methods: New Zealand white rabbits were inoculated with VX2 tumor cell suspension in the right lower lung and treated with microwave ablation after 2-3 weeks of tumor formation. Blood was collected at 5 time points (TP1~TP5) before and after ablation by cardiac blood sampling and pre-treated before proteomic analysis. The plasma proteome was analyzed by Data-Independent Acquisition (DIA). Results: Different molecular pathways were activated at different time points:(i) TP1vsTP2: more proteins were down-regulated and enrichment analysis showed that the proteasome pathway was activated. The abnormal protein folding process involved in this pathway is closely related to the process of tumor development. (ii) TP2vsTP3: more proteins were up-regulated although the number of differentially differentiated proteins was lower and enrichment analysis showed that the phagosome pathway was activated. After microwave ablation inactivates tumor cells, it activates the phagosomal pathway for immune clearance of necrotic tumor tissue. (iii) TP3vsTP4: more down-regulated proteins, enrichment analysis showed that cysteine and methionine metabolism pathway was activated. Decreased metabolism of these amino acids suggests that cancer progression may be blocked after microwave ablation therapy. (iv) TP4vsTP5: the number of differential proteins was less and more down-regulated proteins, enrichment analysis showed that glutathione metabolism and metabolism of xenobiotics by cytochrome P450 pathway were activated. The down-regulated proteins in this pathway may suggest that microwave ablation may have reduced resistance to certain chemotherapeutic agents following. Conclusions: In the process of lung cancer treatment by microwave ablation, the changes of proteins on the possible molecular pathways at each time point are related to lung cancer, and not only involve some simple inflammatory reactions, and some of the proteins released by destroying the tumor cells can be used as possible drug binding sites and reduce drug resistance. [ABSTRACT FROM AUTHOR]

Object: Microwave ablation has been widely used in tumor treatment, and the antenna is a critical component of microwave ablation. We aimed to evaluate a single-slot antenna to generate a small volume ablation zone (0. 5 ∼ 4 cm 3) in adrenal tissue. Methods: A three-dimensional numerical model of the adrenal tissue was built and solved by the Finite Element Method. In the simulation model, the slot antenna was placed between the adrenal gland and fat, and the microwave ablation power and time were adjusted to obtain the target ablation zone. In ex vivo experiments, the length and width of the ablation zone were measured, and the significance of ablation parameters on it was determined using a multi-factorial analysis of variance method. The temperature versus time curves at 3 mm and 7 mm from the antenna were plotted to validate the simulation. Results: The simulation results showed that the combination of microwave ablation parameter settings 30 W/300 s, 40 W/180 s, and 40 W/300 s could create ablation zones in the adrenal tissue volumes of 1. 4 , 1. 1 7 and 3. 2 8 cm 3 , respectively, with minimal damage (less than 0. 1 8 cm 3) to the surrounding fat tissue. Both power and heating time significantly affected the length and width of the ablation zone. The temperature rise curves obtained in the simulation and ex vivo experiments were in good agreement. Conclusion: This work shows that utilizing a slot antenna can produce a small volume ablation zone in adrenal tissue for microwave ablation of benign adrenal adenomas. [ABSTRACT FROM AUTHOR]

Objective of this review is to summarize the latest views of ablation from a prospective of fertility protection, endeavor to clarify the clinical value of thermal ablation technology in protecting fertility by assessing parameters such as ablation rates, alleviation of disease symptoms, re-intervention rates and post-treatment pregnancy rates. We review the clinical studies of ablation for uterine fibroids and adenomyosis treatment in the past 10 years, summarize the limitation and the prospects of its development in the treatment process, so as to provide clinicians with advice on the best practice. In the management of uterine fibroids and adenomyosis, thermal ablation technology offers improved fertility preservation and minimizes normal tissue injury compared to traditional surgical approaches for patients pursuing reproductive goals. In the future, thermal ablation technology will play a significantly enhanced role in preserving fertility for individuals requiring treatment for uterine fibroids and adenomyosis, guided by indications. But further research is still needed in the form of more extensive randomized prospective trials to provide stronger evidence supporting this perspective. [ABSTRACT FROM AUTHOR]

Background: Interventional radiology techniques have become pivotal in recent years in managing metastatic bone disease, which frequently results in skeletal complications such as fractures and severe pain. Thermoablative methods like radiofrequency ablation (RFA) and microwave ablation (MWA), when combined with vertebroplasty (VP), are proving increasingly beneficial for these patients. Methods: The search was independently conducted by two radiologists on MEDLINE databases, using specified strings up to April 2024. Methodological quality was assessed using PRISMA guidelines. Studies meeting inclusion criteria investigated thermoablation techniques (RFA and/or MWA) combined with VP, focusing on pain management and disease control outcomes in adults. Results: Among 147 results, 42 articles met the criteria, with varied prospective and retrospective designs and sample sizes averaging 49 patients, predominantly involving RFA (30 studies), MWA (11 studies), and one comparative study. Our review highlights significant pain reduction, effective local tumor control, and favorable safety of combined RFA or MWA with VP, supporting its potential in managing vertebral pathologies and warranting further clinical integration. Conclusions: The combined treatment of RFA/MWA with VP demonstrates significant pain reduction and local tumor control, with a rapid onset of analgesic effect. These findings support its crucial role in clinical practice for managing vertebral metastases. [ABSTRACT FROM AUTHOR]

Introduction: Recurrence after microwave ablation (MWA) has not been extensively studied. We aimed to investigate the patterns, treatments, and survival of patients with hepatocellular carcinoma (HCC) who experienced early and late recurrence after MWA. Methods: This retrospective study included patients with HCC recurrence after MWA as the initial treatment from January 2008 to December 2021. Recurrence patterns, treatments, and outcomes between patients with early and late HCC recurrence were compared. Prognostic factors of post-recurrence survival (PRS) were identified by multivariable Cox regression analyses. Results: Among 222 patients, 128 developed early recurrence (≤2 years after MWA) and 94 had late recurrence (>2 years). Majority of the recurrent HCC were intrahepatic-only recurrence, within the Milan criteria, and received potentially curative treatment. No significant differences in the recurrence patterns, vascular invasion, tumor staging, post-recurrence treatments, or median PRS (35.0 vs. 33.0 months, p = 0.523) were identified between patients with early and late recurrence. Multivariable analyses suggested that multiple tumor number (hazard ratio [HR]: 1.54; 95% CI: 1.03–2.30, p = 0.038), extrahepatic recurrence (HR: 2.14, 95% CI: 1.16–3.92, p = 0.015), vascular invasion (HR: 2.37, 95% CI: 1.18–4.76, p = 0.038), and higher ALBI grade (HR: 2.18, 95% CI: 1.54–3.08, p < 0.001) were independent risk factors of worse PRS, while curative treatment after recurrence (HR: 0.59, 95% CI: 0.38–0.92, p = 0.020) was associated with better PRS. Conclusions: No differences in recurrence patterns, post-recurrence treatments, or PRS were found between HCC patients with early and late recurrence following MWA. Tumor burden and patients' liver function reserve should be considered to decide the optimal post-recurrence treatment after MWA. [ABSTRACT FROM AUTHOR]

The aim of the current study was to evaluate the feasibility and effectiveness of CT-guided microwave ablation (MWA) in the treatment of osteoid osteomas (OO). Data from 59 consecutive patients who underwent percutaneous CT-MWA for OO treatment were examined in the current retrospective study. The period of this study spanned from January 2021 to May 2023 at a single institution. The study involved an evaluation of clinical and radiological characteristics, procedural data, Visual Analog Scale (VAS) pain scores, complication incidences, as well as clinical and technical success rates. Statistical analyses were performed by using the Wilcoxon test with Bonferroni correction, Friedman, Spearman, Mann–Whitney U test. 59 patients with an average age of 17.31 ± 8.53 years underwent CT-guided MWA for the treatment of OO. The procedure demonstrated a high success rate, with 96.6% of cases achieving both technical and clinical success. However, recurrence was observed in two patients (3.4%) at the three-month follow-up. These cases were successfully managed with a second MWA procedure. The median VAS pain scores reported by the patients was significantly improved post-procedure: from 8.64 ± 1.14 before treatment to 0.63 ± 0.98 in the first month, 0.41 ± 1.02 in the third month, and 0.15 ± 0.45 in the sixth month. Only one patient (1.7%) experienced a minor complication; no major complications were recorded in this study. CT-guided percutaneous MWA is a minimally invasive and a highly effective and safe approach for the treatment of OO. [ABSTRACT FROM AUTHOR]

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Objective: Hepatocellular carcinoma (HCC) is a common cancer. The primary treatment is surgery or liver transplantation. Percutaneous ablation techniques constitute the primary treatment in patients who are not suitable for surgery. Although it gives successful results, some studies report a recurrence rate of up to 50%. This study aimed to obtain an idea about the possibility of possible recurrence by evaluating the lesion characteristics in the pre-procedural MRI images of patients with and without recurrence. Methods: Forty-eight patients who underwent microwave ablation for HCC in our center between 2018 and 2021 were included in the study. Lesion size, presence of peripheral enhancement, arterial contrast enhancement, and T2 signal characteristics were evaluated on pre-procedural MRI. Subsequently, the relationship of these features with tumor recurrence was evaluated. Results: The risk of recurrence was higher in patients with lesion sizes with larger than 3 cm diameter and in lesions showing peripheral contrast enhancement (p= 0.036 and p= 0.021, respectively). Conclusion: Close follow-up will be beneficial in HCCs larger than 3 cm and showing peripheral enhancement since there is a high probability of recurrence after ablation. [ABSTRACT FROM AUTHOR]

Microwave ablation (MWA) plays a crucial role in non-surgical liver cancer treatment, but the existing efficacy evaluation tools lack the characteristics of being real-time, non-invasive, and efficient. As an emerging imaging technology, thermoacoustic imaging (TAI) has attracted extensive clinical attention for its excellent merits, which combine the advantages of high contrast in microwave imaging and high resolution in ultrasound imaging. Particularly, the application of a circular scanned single-channel data acquisition system maximizes the capture of thermoacoustic signals, thereby providing more comprehensive image information and rendering reconstructed images closer to reality. This study aimed to verify the feasibility of TAI in non-invasive evaluation of the efficacy of MWA on ex vivo porcine liver and in vivo rabbit liver. During the experiments, ultrasound is used to cross-verify the results of TAI to ensure the accuracy and reliability of the method. Additionally, by altering the thickness of porcine liver tissue to increase the distance (from 0 mm to 80 mm) between the horn antenna and the target (soy sauce tube), TAI is used to observe the change of the image signal-to-noise ratio to preliminarily explore the imaging depth of TAI. The results of ex and in vivo experiments can not only promote the clinical application of TAI, but also be expected to provide a more accurate and reliable efficacy assessment method for MWA in liver cancer treatment. [ABSTRACT FROM AUTHOR]

Abstract To verify the treatment effect of the combination of transpulmonary chemoembolization (TPCE) and microwave ablation (MWA), targeting the treatment of recurrent or advanced non-small cell lung cancer (NSCLC). A total of 53 patients were studied and grouped according to the diameter of the largest pulmonary nodule, defined as index tumor size (ITS). Patients with an ITS > 3 cm (n = 20) were treated with TPCE and MWA. Patients with an ITS ≤ 3 cm were treated either with a combination therapy (n = 24) or MWA alone (n = 9). The treatment response, including complications and survival outcome, was then analyzed. After TPCE, there was an average ITS reduction of 0.91 cm, and 25% of patients in ITS > 3 cm were downgraded to ITS ≤ 3 cm. After TPCE, there were 12 patients (27%) with PR status and 32 (73%) with SD status. No PD patient in our case series was noted before MWA.The complication rate of MWA was significantly higher in ITS ≤ 3 cm than in ITS > 3 cm (p = 0.013). The median survival time (MST) was 26.7 months, and the time to progression was 13.2 months. The patients in the ITS ≤ 3 cm had longer MST than the others (31.6 vs. 15.8 months, p = 0.003). The significant prognostic factor was ITS > 3 cm (HR: 1.18, p = 0.02). A combination of TPCE and MWA might be feasible to control non-operable, recurrent, or advanced NSCLC.

Chuxiao Zhang, Yuelan Qin, Yangguang Song, Yingying Liu, Xiaodong Zhu Department of Radiation Oncology, Guangxi Medical University Cancer Hospital, Nanning, Guangxi, People’s Republic of ChinaCorrespondence: Xiaodong Zhu, Department of Radiation OncologyGuangxi Medical University Cancer Hospital, No. 71 hedi Road, Nanning, Guangxi, 530021, People’s Republic of China, Email xdzhu1466@hotmail.comPurpose: There are insufficient data about the optimal treatment for older patients with recurring medium or large hepatocellular carcinoma (HCC). The study intended to assess the effect of transcatheter arterial chemoembolization combined with microwave ablation (TACE-MWA) in an elderly cohort through a retrospective analysis.Methods: From 2011 to 2018, a cohort of individuals (age ≥ 70 years) with recurrent HCC tumors ranging from 3.1 cm to 7 cm underwent either a combination treatment of TACE and MWA (n = 43) or surgical intervention (n = 33). Using the Inverse Probability of Treatment Weighting (IPTW) technique, factors of disease-free survival (DFS), overall survival (OS), and rates of major adverse events were analyzed, retrospectively.Results: The group that underwent surgery had a greater history of alcohol use before treatment (P= 0.001), as well as a higher Barcelona Clinic Liver Cancer (BCLC) stage for the primary tumor before treatment (P= 0.014) and a higher primary tumor location before treatment (P= 0.045). The TACE-MWA group had DFS rates of 86.2%, 68.8%, and 60.4% at 1, 3, and 5 years, while the surgery group had rates of 53.0%, 42.2%, and 25.8% at the same time points. In the TACE-MWA treatment group, survival rates at 1 year, 3 years, and 5 years post-treatment were recorded as 93.0%, 80.8%, and 65.7%, respectively, while in the surgery group, they were 62.7%, 46.9%, and 42.6%. In the univariate analysis using IPTW, the type of treatment was found to have a significant correlation with disease progression (hazard ratio [HR] 0.41, 95% CI 0.20– 0.86, P=0.017). IPTW multivariate analysis showed that treatment modality (HR, 0.35; 95% CI, 0.17 to 0.79; P= 0.011) was the only significant prognostic factor for OS.Conclusion: In elderly patients with recurrent 3.1 cm≤ HCC ≤ 7 cm, TACE-WMA was superior to surgery in the respects of DFS and OS.Keywords: elderly patients, hepatocellular carcinoma, transcatheter arterial chemoembolization, microwave ablation, treatment modality

Zhipeng Lin, Xiaolong Hu, Dabei Huang, Xugong Zou, Yuan Chen, Xiaoqun Li, Jian Zhang Department of Interventional Medicine, Zhongshan People’s Hospital, Guangdong, 528400, People’s Republic of ChinaCorrespondence: Jian Zhang, Email wy18988583838@163.comPurpose: Evaluating the clinical efficacy and safety of microwave ablation combined with percutaneous osteoplasty (MWA + PO group) versus percutaneous osteoplasty (PO group) for the treatment of flat bone metastases.Methods: Patients with flat bone metastases and intractable pain who underwent PO and/or MWA from January 2016 to January 2023 in our hospital were included, with 36 cases in the MWA+PO group and 21 cases in the PO group. Changes in the visual analog scale (VAS), Oswestry Disability Index (ODI), and quality of life assessment scale(QOL) were evaluated regularly. Postoperative complications and target lesion tumor treatment responses were also observed.Results: The VAS and ODI in both the MWA+PO group and the PO group significantly decreased at 1 week, 1 month, and 3 months postoperatively, The VAS and ODI in the MWA+PO group were lower than those in the PO group postoperatively. The QOL in both the MWA+PO group and the PO group significantly increased at 1 week, 1 month, and 3 months postoperatively, with the QOL in the MWA+PO group being higher than that in the PO group postoperatively. According to the mRECIST criteria (target lesion tumor treatment response), the ORR in the MWA+PO group and PO group was 52.8% and 9.5%, respectively, while the DCR was 94.4% and 57.1%, respectively (P < 0.001 and< 0.001). Different degrees of bone cement extravasation were observed in both the PO group (38.1%) and MWA+PO group(19.4%)(χ²=2.38, P=0.12), but none of the patients developed clinical symptoms related to bone cement extravasation. The average cost of surgery was ¥ 10,480.43 higher in the MWA+PO group than in the PO group.Conclusion: The MWA+PO treatment is more effective in relieving patients’ local pain, improving local dysfunction, and enhancing quality of life, and can effectively improve target lesion tumor ORR and DCR, but it is also more costly.Keywords: microwave ablation, percutaneous osteoplasty, bone metastases

Abstract Background To evaluate the safety and efficacy of percutaneous biopsy and microwave ablation (B + MWA) in patients with pulmonary nodules (PNs) who are receiving antithrombotic therapy by rivaroxaban as bridging therapy. Methods The study comprised 187 patients with PNs who underwent 187 B + MWA sessions from January 1, 2020, to December 31, 2021. The enrolled patients were divided into two groups: Group A, who received antithrombotic therapy five days before the procedure and received rivaroxaban as a bridging drug during hospitalization, and group B, who had no antithrombotic treatment. Information about the technical success rate, positive biopsy rate, complete ablative rate, and major complications were collected and analyzed. Results Group A comprised 53 patients and group B comprised 134 patients. The technical success rate was 100% in both groups. The positive biopsy rates were 88.68% and 91.04%, respectively (p = 0.6211, X2 = 0.2443). In groups A and B, the complete ablative rates at 6, 12, and 24 months were 100.0% versus 99.25%, 96.23% versus 96.27%, and 88.68% versus 89.55%, respectively. There were no significant differences in bleeding and thrombotic complications between the two groups. No grade 5 complications occurred. Conclusions It is generally considered safe and effective that patients who are on antithrombotic therapy by rivaroxaban as bridging to undergo B + MWA for treating PNs.

Abstract Background Microwave ablation (MWA) is widely used to eliminate colorectal liver metastases (CRLM). However, the risk of tumor recurrence is difficult to predict due to lack of reliable clinical and biological markers. Elevation of gamma-glutamyl transferase (GGT) and aspartate transaminase (AST) provides signals for liver inflammation and cancer progression. The present study evaluated the association between pre-ablation GGT to AST ratio index (GSR) and hepatic recurrence in patients with CRLM after MWA. Methods A retrospectively analyzed 192 CRLM patients who underwent MWA from January 2013 to December 2017. Pre-ablation GSR was classified into high (≤ 2.34) or low (> 2.34) using the upper quartile value. The prognostic value of GSR and other risk factors for liver progression-free survival (LPFS) and cancer-specific survival (CSS) were evaluated by univariate and multivariate analyses. Results High GSR was significantly associated with males (P = 0.041), the presence of cholelithiasis (P = 0.012), but not pre-ablation chemotherapy (P = 0.355), which caused significantly increased levels of GGT (P = 0.015) and AST (P = 0.008). GSR showed a significant association with LPFS and CSS through univariate analysis (P = 0.002 and 0.006) and multivariate analysis (P = 0.043 and 0.037). The subgroup analysis demonstrated no interaction between GSR and all variables except for distribution in the sub-analysis of LPFS. Conclusions Our findings suggest that the pre-ablation GSR can be considered as a promising prognostic indicator for poor prognosis of patients with CRLM underwent MWA. Trial registration Not applicable.

Backgrounds/Aims Atezolizumab/bevacizumab is the recommended first-line systemic therapy for unresectable hepatocellular carcinoma (uHCC) and may facilitate curative conversion through resection and locoregional therapies. However, there have been very few reports on curative conversion using microwave ablation (MWA). This study aimed to determine the curative conversion rate with MWA using atezolizumab-bevacizumab as the first-line treatment in patients with uHCC, and to compare the characteristics and survival of patients with and without curative conversion. Methods Consecutive patients with uHCC who were started on atezolizumab-bevacizumab from May 2021 to December 2023 in a single tertiary center were included. Objective response rate (ORR) and disease control rate (DCR) were based on the Response Evaluation Criteria In Solid Tumors (RECIST) 1.1 and modified RECIST (mRECIST) criteria. Results Twenty consecutive patients with uHCC (60% advanced-stage) were included, 90% exceeding the up-to-7 criteria. The ORR and DCR were 35% and 60%, 35% and 55% using RECIST and mRECIST, respectively. Five patients (25%) underwent successful curative conversion with MWA (four advanced and one intermediate stage) despite a median HCC size of 6.1 cm (range, 2.4-7.3). Two of these patients were tumor and drug-free 132-133 weeks from the 1st atezolizumab-bevacizumab dose. Patients who underwent curative conversion had significantly longer survival than those who did not (P=0.024). Other factors associated with survival were male sex, Child-Pugh class A, and an objective response. Conclusions Despite the relatively large tumor size, successful curative conversion with MWA was achieved with first-line atezolizumab-bevacizumab in uHCC. However, data from prospective multicenter trials are required to determine whether this strategy is universally applicable.

Background: Interventional radiology techniques have become pivotal in recent years in managing metastatic bone disease, which frequently results in skeletal complications such as fractures and severe pain. Thermoablative methods like radiofrequency ablation (RFA) and microwave ablation (MWA), when combined with vertebroplasty (VP), are proving increasingly beneficial for these patients. Methods: The search was independently conducted by two radiologists on MEDLINE databases, using specified strings up to April 2024. Methodological quality was assessed using PRISMA guidelines. Studies meeting inclusion criteria investigated thermoablation techniques (RFA and/or MWA) combined with VP, focusing on pain management and disease control outcomes in adults. Results: Among 147 results, 42 articles met the criteria, with varied prospective and retrospective designs and sample sizes averaging 49 patients, predominantly involving RFA (30 studies), MWA (11 studies), and one comparative study. Our review highlights significant pain reduction, effective local tumor control, and favorable safety of combined RFA or MWA with VP, supporting its potential in managing vertebral pathologies and warranting further clinical integration. Conclusions: The combined treatment of RFA/MWA with VP demonstrates significant pain reduction and local tumor control, with a rapid onset of analgesic effect. These findings support its crucial role in clinical practice for managing vertebral metastases.

Abstract Objective To compare therapeutic outcomes of predicted proliferative and nonproliferative hepatocellular carcinoma (HCC) after microwave ablation (MWA) using a previously developed imaging-based predictive model, the SMARS score. Methods This multicenter retrospective study included consecutive 635 patients with unresectable HCC who underwent MWA between August 2013 and September 2020. Patients were stratified into predicted proliferative and nonproliferative phenotypes according to the SMARS score. Overall survival (OS) and recurrence-free survival (RFS) were compared between the predicted proliferative and nonproliferative HCCs before and after propensity score matching (PSM). OS and RFS were also compared between the two groups in subgroups of tumor size smaller than 30 mm and tumor size 30–50 mm. Results The SMARS score classified 127 and 508 patients into predicted proliferative and nonproliferative HCCs, respectively. The predicted proliferative HCCs exhibited worse RFS but equivalent OS when compared with nonproliferative HCCs before (p < 0.001 for RFS; p = 0.166 for OS) and after (p < 0.001 for RFS; p = 0.456 for OS) matching. Regarding subgroups of tumor size smaller than 30 mm (p = 0.098) and tumor size 30–50 mm (p = 0.680), the OSs were similar between the two groups. However, predicted proliferative HCCs had worse RFS compared to nonproliferative HCCs in the subgroup of tumor size 30–50 mm (p < 0.001), while the RFS did not differ in the subgroup of tumor size smaller than 30 mm (p = 0.141). Conclusion Predicted proliferative HCCs have worse RFS than nonproliferative ones after MWA, especially in tumor size larger than 30 mm. However, the phenotype of the tumor may not affect the OS. Critical relevance statement Before performing microwave ablation for hepatocellular carcinoma, the tumor phenotype should be considered because it may affect the therapeutic outcome. Key Points Proliferative hepatocellular carcinoma (HCC) may be identified using the SMARS score, an imaging-based predictive model. SMARS predicted proliferative HCCs have worse recurrence-free and equivalent overall survival compared to nonproliferative HCC after microwave ablation. Tumor phenotype should be considered before performing microwave ablation. Graphical Abstract

Microwave ablation is becoming an increasingly important minimally invasive procedure that uses dielectric hysteresis to generate heat and destroy cancer cells. Tissue damage depends on the input power, procedure duration, and antenna position. Therefore, one of the essential problems is determining parameters that ensure the destruction of the tumor with the desired margins and minimal damage to the healthy tissue. In addition to experimental methods, computer modeling has been proven to be an effective approach for improving the performance of microwave ablation (MWA). Moreover, since the thermal spread in biological tissue is difficult to measure, the development of a predictive model from procedural planning to execution may have a great impact on patient care. This study focuses on determining the optimal parameters for MWA treatment of liver tumors using two identical parallel-positioned multi-slot coaxial antennas. The simulation results suggest that an input power of 20 W or 15 W per antenna suffices for complete tumor ablation with a sufficient safety margin for 600 and 900 s, respectively. In both cases, the created ablation zones were similar. The ablation zones for 15 W per antenna were more spherical, invading a smaller amount of healthy tissue than those for 20 W per antenna. This study may represent a step forward in planning MWA treatment for individual patients.

The upper urinary tract is the most common human organ system affected by congenital anomalies. A Horseshoe kidney is a fusion anomaly, it can be described as a fusion across the midline of 2 distinct functioning kidneys. The incidence of renal tumors in a Horseshoe kidney is higher than in the normal population.We present a 60-year-old male patient with a history of Horseshoe kidney and a diagnosis of clear cell renal cell carcinoma who underwent a combined therapeutic approach, guided by interventional radiology. This approach involved selective transarterial embolization and microwave ablation. Three months after surgery and with abdominal MRI follow-up, there is evidence of a non-viable tumor, indicating a favorable response to the intervention.

Abstract Background Giant cell tumor of bone (GCTB) is a locally aggressive neoplasm with a high propensity for recurrence following intralesional curettage. The introduction of denosumab, a RANKL inhibitor, has shown potential in facilitating joint-sparing surgery. However, concerns exist regarding its impact on local recurrence rates. This study aimed to evaluate the efficacy and safety of combined preoperative denosumab with adjuvant microwave ablation (MWA) for the treatment of high-risk GCTB. Methods We conducted a retrospective review of 19 patients with high-risk GCTB who underwent preoperative denosumab treatment followed by curettage and adjuvant MWA. The primary outcome measure was the local recurrence rate, with secondary outcomes including functional status assessed by the Musculoskeletal Tumor Society (MSTS) score and safety profile of the treatment. Results In this retrospective analysis, we evaluated the outcomes of 19 patients with high-risk GCTB treated with preoperative denosumab and adjuvant MWA. The median follow-up duration was 33.1 months, 3 patients (15.8%) experienced local recurrence at a median of 21.6 months postoperatively and the local recurrence-free survival was 81.2% at two years. Notably, no patient developed lung metastasis, and all recurrences were successfully managed with repeat curettage and MWA, with a mean MSTS score of 27.3. No patient required joint replacement due to tumor recurrence, resulting in a 100% joint preservation rate. Conclusion The combination of preoperative denosumab and adjuvant MWA is a feasible and effective strategy for the management of high-risk GCTB, providing effective local control with preserved joint function. This approach may offer a surgical alternative for young patients where joint preservation is paramount.

Introduction: Percutaneous microwave ablation (MWA) is clinically accepted for the treatment of lung tumors and oligometastatic disease. Bronchoscopic MWA is under development and evaluation in the clinical setting. We previously reported on the development of a bronchoscopy-guided MWA system integrated with clinical virtual bronchoscopy and navigation and demonstrated the feasibility of transbronchial MWA, using a maximum power of 60 W at the catheter input. Here, we assessed the performance of bronchoscopy-guided MWA with an improved catheter (maximum power handling of up to 120 W) in normal porcine lung in vivo (as in the previous study). Methods: A total of 8 bronchoscopy-guided MWA were performed (n = 2 pigs; 4 ablations per pig) with power levels of 90 W and 120 W applied for 5 and 10 min, respectively. Virtual bronchoscopy planning and navigation guided transbronchial or endobronchial positioning of the MWA applicator for ablation of lung parenchyma. Following completion of ablations and post-procedure CT imaging, the lungs were harvested and sectioned for gross and histopathologic ablation analysis. Results: Bronchoscopy-guided MWA with applied energy levels of 90 W/5 min and 120 W/10 min yielded ablation zones with short-axis diameters in the range of 20–28 mm (56–116% increase) as compared to ∼13 mm from our previous study (60 W/10 min). Histology of higher-power and previous lower-power ablations was consistent, including a central necrotic zone, a thermal fixation zone with intact tissue architecture, and a hemorrhagic periphery. Catheter positioning and its confirmation via intra-procedural 3D imaging (e.g., cone-beam CT) proved to be critical for ablation consistency. Conclusion: Bronchoscopy-guided MWA with an improved catheter designed for maximum power 120 W yields large ablations in normal porcine lung in vivo.

Jing Sang,1,2,&ast; Peng Liu,1,3,&ast; Meixiang Wang,1 Fengkuo Xu,1 Ji Ma,1 Zhigang Wei,1 Xin Ye1 1Department of Oncology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Lung Cancer Institute, Shandong Key Laboratory of Rheumatic Disease and Translational Medicine, Jinan, People’s Republic of China; 2Department of Pathology, The Affiliated Taian City Central Hospital of Qingdao University, Taian, People’s Republic of China; 3Yuncheng Central Hospital Affiliated to Shanxi Medical University, Yuncheng, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Zhigang Wei; Xin Ye, Department of Oncology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, Shandong Province, 250014, People’s Republic of China, Email weizhigang321321@163.com; yexintaian2020@163.comPurpose: Microwave ablation (MWA) is a minimally invasive technique for treating lung cancer. It can induce immune response; however, its effect on the immune microenvironment in tumor-draining lymph nodes (TdLN) is not well understood. This study aims to identify changes in the immune microenvironment in TdLN following MWA in a Lewis lung cancer (LLC) mouse model.Methods: LLC mouse model was established and followed by MWA. TdLN were collected at various time points, including pre-MWA and days 1, 2, 4, and 8 post-MWA. Flow cytometry was used to determine the frequencies of CD4+ T cells, CD8+ T cells, regulatory T (Treg) cells, natural killer (NK) cells, dendritic cells (DCs) and other immune cells in the TdLN. Certain cytokines were also detected.Results: Compared with pre-MWA, the frequency of CD4+ T cells significantly increased from day 1 to day 8 post-MWA. The frequency of CD8+ T cells decreased significantly on days 2 and 4, but no significant changes occurred on days 1 and 8. Significant decreases in the frequencies of Treg cells and Klrg1+ Treg cells were observed from day 1 to day 4. On days 4 and 8, there was a significant increase in the frequency of NK cells. The frequency of resident cDC2 significantly increased on day 4, whereas CD11b+ migratory cDCs increased on day 1. Additionally, on day 4, a notable rise was observed in the frequency of NK cells secreting IFN-γ, while on day 8, there was a significant increase in the frequency of CD8+ T cells secreting both IFN-γ and TNF-α.Conclusion: MWA of lung cancer can alter the immune microenvironment in the TdLN, triggering immune responses. These changes are particularly evident and intricate within the initial 4 days post-MWA. Treatment combined with MWA within a certain period may significantly enhance anti-tumor immunity.Keywords: microwave ablation, lung cancer, T cells, regulatory T cells, natural killer cells, dendritic cells

Abstract Aim Clinical diagnosis and surgical treatment of chondrosarcoma (CS) are continuously improving. The purpose of our study is to evaluate the effectiveness of microwave ablation (MWA) assisted degradation therapy in the surgical treatment of intramedullary chondrosarcoma of the extremities, to provide a new reference and research basis for the surgical treatment of CS. Methods We recruited 36 patients with intramedullary CS who underwent MWA assisted extended curettage. Preoperative patient demographics and clinical data were recorded. Surgery was independently assisted by a medical team. Patients were followed up strictly and evaluated for oncological prognosis, radiological results, limb joint function, pain, and complications. Results We included 15 men and 21 women (mean age: 43.5 ± 10.1). The average length of the lesion was 8.1 ± 2.5 cm. Based on preoperative radiographic, clinical manifestations, and pathological results of puncture biopsy, 28 patients were preliminarily diagnosed with CS-grade I and eight patients with CS-grade II. No recurrence or metastasis occurred in the postoperative follow-up. The average Musculoskeletal Tumor Society score was 28.8 ± 1.0, significantly better than presurgery. Secondary shoulder periarthritis and abduction dysfunction occurred in early postoperative stage CS of the proximal humerus in some, but returned to normal after rehabilitation exercise. Secondary bursitis occurred at the knee joint in some due to the internal fixation device used in treatment; however, secondary osteoarthritis and avascular necrosis of the femoral head were not observed. Overall, oncological and functional prognoses were satisfactory. Conclusions The application of MWA assisted degradation therapy in intramedullary CS can achieve satisfactory oncology and functional prognosis, providing a new option for the limited treatment of CS.

Microwave ablation is a minimally invasive cancer treatment with high survival and low recurrence rates. Despite the unquestionable benefits of microwave ablation, the interaction between the medical tool and the tissue may cause damage to the surrounding tissue, which can be removed by clarifying the conditions for their development. In addition to clinical methods, computer simulation has proven to be a very effective tool to optimize microwave ablation performance. This study aimed to determine the optimal input power for complete microwave tumor ablation with an adequate safety margin while avoiding injury to surrounding healthy tissue. The liver tumor model was based on a real tumor labeled 1.02 in the 3D-IRCADb-01 database. Calculations were performed for a 10-slot microwave antenna with a frequency of 2.45 GHz using COMSOL Multiphysics. The obtained simulation results revealed that with proper input power, the necrotic tissue was mainly located in the tumor with minimal damage to the surrounding healthy tissue. This study may represent a step forward in planning individual microwave ablation procedures for each patient.

Objectives There is still controversy over the choice of treatment for end‐stage spinal metastases. With the continuous development of microwave technology in spinal tumors, related studies have reported that microwave combined with techniques such as pedicle screw fixation and percutaneous vertebroplasty can achieve the purpose of tumor ablation, relieving spinal cord compression, enhancing spinal stability, effectively relieving pain, and reducing recurrence rates. This study aimed to analyze the effectiveness of microwave ablation combined with decompression and pedicle screw fixation in the palliative management of spinal metastases with pathological fractures. Methods This retrospective study enrolled 82 patients with spinal metastases and pathological fractures treated between January 2016 and July 2020, with 44 patients undergoing pedicle screw fixation along with laminectomy (fixation group) and the remaining 38 receiving microwave ablation in addition to the treatment provided to group fixation (MWA group). Before surgery, all patients underwent pain assessment using the visual analogue scale (VAS) and evaluation of spinal cord injury using the Frankel classification. After surgery, the patients' prognoses were assessed using the Tomita score, modified Tokuhashi score system, and progression‐free survival. Additionally, we compared operative time and blood loss between the two groups. Survival analysis utilized the Kaplan–Meier method with a log‐rank test for group comparisons. Paired t‐tests and the Mann–Whitney U test were applied to metric and non‐normally distributed data, respectively. Neurological function improvement across groups was evaluated using the χ2 test. Results All patients were followed up for a median duration of 18 and 20 months in the fixation and MWA groups, respectively, with follow‐up periods ranging from 6 to 36 months. Statistically significant reductions in postoperative VAS scores were observed in all patients compared with their preoperative scores. The MWA group exhibited reduced blood loss (t = 2.74, p = 0.01), lower VAS scores at the 1‐ and 3‐month follow‐ups (t = 2.34, P = 0.02; t = 2.83, p = 0.006), and longer progression‐free survival than the fixation group (p = 0.03). Although the operation times in the MWA group were longer than those in the fixation group, this difference was not statistically significant (t = 6.06, p = 0.12). No statistically significant differences were found regarding improvements in spinal cord function between the two groups (p = 0.77). Conclusion Compared with decompression and pedicle screw fixation for treating spinal metastases with pathological fractures, microwave ablation combined with decompression and pedicle screw fixation showed better outcomes in terms of pain control, longer progression‐free survival, and lower blood loss without increasing operative time, which has favorable implications for clinical practice.

Ultrasound is an indispensable tool for intraoperative assessment and treatment of hepatopancreatobiliary pathology. As minimally invasive approaches to HPB surgery continue to expand and the benefits of parenchymal-sparing liver surgery are increasingly appreciated, skillful targeting will play an even bigger role in HPB surgical practice. Techniques for intraoperative targeting of liver lesions for the purposes of biopsy and ablation, particularly in the laparoscopic setting, are the focus of this chapter.Current evidence supports the use of ablation for a variety of liver lesions including hepatocellular carcinoma and metastatic colorectal cancer, particularly for smaller lesions.Successful targeting requires optimization of patient position and port placement. When targeting multiple lesions, thoughtful treatment sequencing is critical to maintaining visualization and optimizing outcomes.

Adrenal gland-induced hypertension results from underlying adrenal gland disorders including Conn's syndrome, Cushing's syndrome, and Pheochromocytoma. These adrenal disorders are a risk for cardiovascular and renal morbidity and mortality. Clinically, treatment for adrenal gland-induced hypertension involves a pharmaceutical or surgical approach. The former presents very significant side effects whereas the latter can be ineffective in cases where the adrenal disorder reoccurs in the remaining contralateral adrenal gland. Due to the limitations of existing treatment methods, minimally invasive treatment options like microwave ablation (MWA) have received significant attention for treating adrenal gland disorders. A precise comprehension of the dielectric properties of human adrenal glands will help to tailor energy delivery for MWA therapy, thus offering the potential to optimise treatments and minimise damage to surrounding tissues. This study reports the ex vivo dielectric properties of human adrenal glands, including the cortex, medulla, capsule, and tumours, based on the data obtained from four patients (diagnosed with Conn's syndrome, Cushing's syndrome, and Pheochromocytoma) who underwent unilateral adrenalectomy at the University Hospital Galway, Ireland. An open-ended coaxial probe measurement technique was used to measure the dielectric properties for a frequency range of 0.5–8.5 GHz. The dielectric properties were fitted using a two-pole Debye model, and a weighted least squares method was employed to optimise the model parameters. Moreover, the dielectric properties of adrenal tissues and tumours were compared across frequencies commonly used in MWA, including 915 MHz, 2.45 GHz, and 5.8 GHz. The study found that the dielectric properties of adrenal tumours were influenced by the presence of lipid-rich adenomas, and the dielectric properties of Cushing's syndrome tumour were lowest in comparison to the tumours in patients diagnosed with Conn's syndrome and Pheochromocytoma. Furthermore, a notable difference was observed in the dielectric properties of the medulla and cortex among patients diagnosed with Conn's syndrome, Cushing's syndrome, and Pheochromocytoma. These findings have significant implications for the diagnosis and treatment of adrenal tumours, including the optimisation of MWA therapy for precise ablation of adrenal masses. [ABSTRACT FROM AUTHOR]

Objectives: To explore the impact of lymph node diameter on the efficacy and safety of ultrasound-guided microwave ablation (MWA) in the treatment of cervical metastatic lymph nodes (CMLNs) from thyroid cancer. Methods: A total of 32 patients with 58 CMLNs from thyroid cancer underwent ultrasound-guided MWA and were included in the retrospective study. Patients were divided into three groups based on the mean largest diameter of the CMLNs: Group A (diameter =10mm), Group B (10mm < diameter =20mm), and Group C (diameter >20mm). The research involved comparing changes in cervical metastatic lymph nodes and serum thyroglobulin (sTg) levels, as well as the incidence of complications, before and after microwave ablation across three groups of patients. Results: The technical success rate of this study was 100% (32/32), and they showed no major complications. Compared with measurements taken before MWA, the mean largest diameter and volume of CMLNs, as well as the sTg level, showed significant reductions (p <0.05) at the last follow-up in all three patient groups. Group A and B exhibited higher lymph node volume reduction rates and complete disappearance rates compared to Group C. However, the recurrence rate in the three groups were in the following order: Group C > Group B > Group A. The occurrence rate of mild complications was Group A > Group C > Group B. Conclusion: MWA is a safe and effective method for treating CMLNs, with advantages for localized nodes but limitations for larger ones. Careful consideration and personalized plans are advised, based on comprehensive evidence assessment. [ABSTRACT FROM AUTHOR]

Background: Giant cell tumor of bone (GCTB) is a locally aggressive neoplasm with a high propensity for recurrence following intralesional curettage. The introduction of denosumab, a RANKL inhibitor, has shown potential in facilitating joint-sparing surgery. However, concerns exist regarding its impact on local recurrence rates. This study aimed to evaluate the efficacy and safety of combined preoperative denosumab with adjuvant microwave ablation (MWA) for the treatment of high-risk GCTB. Methods: We conducted a retrospective review of 19 patients with high-risk GCTB who underwent preoperative denosumab treatment followed by curettage and adjuvant MWA. The primary outcome measure was the local recurrence rate, with secondary outcomes including functional status assessed by the Musculoskeletal Tumor Society (MSTS) score and safety profile of the treatment. Results: In this retrospective analysis, we evaluated the outcomes of 19 patients with high-risk GCTB treated with preoperative denosumab and adjuvant MWA. The median follow-up duration was 33.1 months, 3 patients (15.8%) experienced local recurrence at a median of 21.6 months postoperatively and the local recurrence-free survival was 81.2% at two years. Notably, no patient developed lung metastasis, and all recurrences were successfully managed with repeat curettage and MWA, with a mean MSTS score of 27.3. No patient required joint replacement due to tumor recurrence, resulting in a 100% joint preservation rate. Conclusion: The combination of preoperative denosumab and adjuvant MWA is a feasible and effective strategy for the management of high-risk GCTB, providing effective local control with preserved joint function. This approach may offer a surgical alternative for young patients where joint preservation is paramount. [ABSTRACT FROM AUTHOR]

Thyroid schwannoma, a rare neoplasm of the thyroid gland, originates from Schwann cells that form the myelin sheath. A 47-year-old woman presented with a progressively enlarging thyroid nodule, which was monitored by repeated ultrasonography over the previous 2 years. Following a diagnosis of thyroid schwannoma by core needle biopsy and immunohistochemical staining, the patient underwent ultrasoundguided microwave ablation (MWA). Subsequent thyroid ultrasounds indicated a gradual decrease in the tumor's volume, achieving a 12-month volume reduction ratio of 79.20%. No complications were observed. Ultrasound-guided MWA may serve as an effective alternative to conventional surgery for managing thyroid schwannomas. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is a chronic, inflammatory systemic disorder of synovial joints and results in polyarthritis, chronical degeneration, and finally deformities and ankylosis in severe cases. Synovitis and pannus formation are results of inflammatory changes and lead into restriction in joint movement. Shoulders are among the later affected and larger joints and formation of synovitis in early active stages and pannus in later stages might be concluded with frozen shoulder and severe impairment in functionality. These late-term changes cannot be controlled with systemic or local anti-inflammatory agents and synovectomy is chosen in some cases. However, the results are not satisfactory and recurrence is common. In this case report, we presented a case of RA with severe shoulder pain, restricted movement due to synovial hypertrophy, and pannus formation which are resistant to local and systemic interventions and not suitable for surgical or chemical synovectomy. Microwave ablation (MWA) was performed successfully without any complication and she well responded in terms of DAS-28, functional, and pain scores. Range of motion and funcitonal restriction were recovered. This case report describes the use and promising results of MWA in RA with severe synovial hypertrophy and pannus formation even in the absence of active arthritis and effusion. MWA is a safe and minimally invasive technique that can be easily performed in coordinance of rheumatologists and interventional radiologists in proper cases. [ABSTRACT FROM AUTHOR]

Despite the success of immune checkpoint inhibitors (ICIs) in treating solid tumors, lots of patients remain unresponsive to this therapy. Microwave ablation (MWA) stimulates systemic adaptive immunity against tumor cells by releasing tumor antigens. Additionally, IL-21 has demonstrated importance in stimulating T-cell effector function. The combination of these three therapies—MWA, IL-21, and anti-PD-1 monoclonal antibodies (mAbs)—has yet to be explored in the context of cancer treatment. In this study, we explored the impact of thermal ablation on IL-21R expression in tumor-infiltrating lymphocytes (TILs). Subsequently, we assessed alterations in the tumor microenvironment (TME) and peripheral lymphoid organs. Additionally, we conducted a thorough examination of tumor-infiltrating CD45+ immune cells across various treatment groups using single-cell RNA sequencing (scRNA-seq). Moreover, we determined the potential anti-tumor effects of the triple combination involving MWA, IL-21, and anti-PD-1 mAbs. Our findings revealed that MWA upregulated the expression of IL-21R on various immune cells in the untreated tumors. The combination of MWA with IL-21 exhibited a robust abscopal anti-tumor effect, enhancing the effector function of CD8+ T cells and facilitating dendritic cells' maturation and antigen presentation in the untreated tumor. Notably, the observed abscopal anti-tumor effect resulting from the combination is contingent upon T-cell recirculation, indicating the reliance of systemic adaptive immunity for this treatment regimen. Additionally, the combination of MWA, IL-21, and PD-1 mAbs demonstrated profound abscopal anti-tumor efficacy. Our findings provide support for further clinical investigation into a triple combination therapy involving MWA, IL-21, and ICIs for the treatment of metastatic cancer. [ABSTRACT FROM AUTHOR]

Elastography is a noninvasive technique for characterizing the mechanical properties of biological tissues. Conventional methods have limitations in resolution and sensitivity, hindering disease detection in clinical diagnostics. To address these issues, this study developed an optical‐resolution photoacoustic microelastography (OR‐PAME) system. Using an agar tissue phantom with varying agar concentrations and contrast agents, PAME evaluated elasticity distribution under compression in both lateral and axial dimensions. It indirectly measured elastic properties by correlating photoacoustic responses, temporal lags, and induced displacement. We also applied the system to the study of the distribution of elastic characteristics of the liver tissue after ablation, which confirmed the potential of OR‐PAME in the study of elastic characteristics. Quantitative analysis showed greater lateral displacement in regions with reduced agar concentrations, indicating decreased stiffness. PAME also detected vertical displacement along the axial plane, validating its efficacy in elastographic imaging. By improving resolution and penetration, PAME provides superior visualization of elasticity distribution. Its methodology correlates microstructural alterations with tissue biomechanics, holding potential implications in medical diagnostics. [ABSTRACT FROM AUTHOR]