Thermal Ablation Treatment Research Articles

Percutaneous ablation treatment in metastatic lung tumors: a single-center experience

In recent years, many studies have proven that percutaneous thermal ablation is an effective second-line treatment method with low complication rates in early-stage non-small cell lung carcinoma and lung metastases. Radiofrequency ablation and microwave ablation are commonly used for this purpose. To evaluate the factors affecting the success of the percutaneous thermal ablation treatment with technical success, complication rates, and long-term follow-up results in metastatic lung lesions. Computed tomography (CT)-guided percutaneous ablation was performed for 70 metastatic lung lesions in 35 patients (22 men, 13 women; mean age = 61.34 years; age range = 41-75 years). Radiofrequency ablation was performed in 53/70 (75.7%) lesions and microwave ablation in 17/70 (24.3%) lesions. The technical success rate was 98.6%. Median overall survival, progression-free survival, and local recurrence-free survival of the patients were 33.9 months (range=25.6-42.1 months), 12 months (range=4.9-19.2 months), and 24.2 months (range=8.2-40.1 months), respectively. One- and two-year overall survival rates were 84% and 74%, respectively. Median progression-free survival times were 20.3 months and 11.4 months, respectively, according to the number of metastatic lung lesions being single and multiple, and the difference was statistically significant (P = 0.046). According to the number of lesions ≤3 and >3, the difference was also found statistically significant (P = 0.024) (14.3 months and 5.7 months, respectively). In conclusion, CT-guided percutaneous thermal ablation is a safe and effective treatment method in metastatic lung lesions. The number of lesions is the most important factor in predicting treatment success.

Sonobiopsy for expanding the application of therapeutic ultrasound in the diagnosis of brain diseases

Focused ultrasound (FUS) was introduced for brain applications in the 1940s and has been employed as a therapeutic tool since then. FUS-mediated thermal ablation treatment of essential tremors was approved by the U.S. Food and Drug Administration (FDA) in 2016. FUS combined with microbubbles for inducing BBB disruption to deliver neurotherapeutic drugs to the brain is currently in early-phase clinical trials. We proposed to use FUS as a brain disease molecular diagnostic tool. Sonobiopsy uses FUS to release brain disease-specificbiomarkers (e.g., DNA, RNA, and proteins) from the brain to the blood for the diagnosis of brain diseases by blood tests. Sonobiopsy does not involve any neurotherapeutic drugs, which may accelerate FDA approval of the FUS technique. Sonobiopsy opens new research opportunities that have the potential to substantially improve the diagnosis of a broad spectrum of brain tumors. This talk will present recent progress in the development of sonobiopsy technique for the diagnosis of brain cancer and Alzheimer’s disease. This talk also will present recent achievements in the clinical translation of sonobiopsy.

Broadband Dielectric Spectroscopy with a Microwave Ablation Antenna

Microwave ablation is a technique used to treat tumorous tissue. Its clinical use has been greatly expanding in the last few years. Because the design of the ablation antenna and the success of the treatment greatly depend on the accurate knowledge of the dielectric properties of the tissue being treated, it is highly valuable to have a microwave ablation antenna that is also able to perform in-situ dielectric spectroscopy. In this work, an open-ended coaxial slot ablation antenna design operating at 5.8 GHz is adopted from previous work, and its sensing abilities and limitations are investigated in respect of the dimensions of the material under test. Numerical simulations were performed to investigate the functionality of the floating sleeve of the antenna and to find the optimal de-embedding model and calibration option for obtaining accurate dielectric properties of the area of interest. Results show that, as in the case of the open-ended coaxial probe, the accuracy of the measurement greatly depends on the likeness between the calibration standards' dielectric properties and the material under test. Finally, the results of this paper clarify to which extent the antenna can be used to measure dielectric properties and paves the way to future improvements and the introduction of this functionality into microwave thermal ablation treatments.

The CXCL10/CXCR3 Pathway Contributes to the Synergy of Thermal Ablation and PD-1 Blockade Therapy against Tumors

As a practical local therapeutic approach to destroy tumor tissue, thermal ablation can activate tumor-specific T cells via enhancing tumor antigen presentation to the immune system. In the present study, we investigated changes in infiltrating immune cells in tumor tissues from the non-radiofrequency ablation (RFA) side by analyzing single-cell RNA sequencing (scRNA-seq) data of tumor-bearing mice compared with control tumors. We showed that ablation treatment could increase the proportion of CD8+T cells and the interaction between macrophages and T cells was altered. Another thermal ablation treatment, microwave ablation (MWA), increased the enrichment of signaling pathways for chemotaxis and chemokine response and was associated with the chemokine CXCL10. In addition, the immune checkpoint PD-1 was especially up-regulated in the infiltrating T cells of tumors on the non-ablation side after thermal ablation treatment. Combination therapy of ablation and PD-1 blockade had a synergistic anti-tumor effect. Furthermore, we found that the CXCL10/CXCR3 axis contributed to the therapeutic efficacy of ablation combined with anti-PD-1 therapy, and activation of the CXCL10/CXCR3 signaling pathway might improve the synergistic effect of this combination treatment against solid tumors.

Inter- and intra-observer agreement in the assessment of the cervical transformation zone (TZ) by visual inspection with acetic acid (VIA) and its implications for a screen and treat approach: a reliability study

BackgroundIn low-resource countries, interpretation of the transformation zone (TZ) using the classification of the International Federation for Cervical Pathology and Colposcopy (IFCPC), adopted by the World Health Organization, is critical for determining if visual inspection with acetic acid (VIA) screening and thermal ablation treatment are possible. We aim to assess inter- and intra-observer agreement in TZ interpretation.MethodsWe performed a prospective multi-observer reliability study. One hundred cervical digital images of Human papillomavirus positive women (30–49 years) were consecutively selected from a Cameroonian cervical cancer screening trial. Images of the native cervix and after VIA were obtained. The images were evaluated for the TZ type at two time points (rounds one and two) by five VIA experts from four countries (Côte d’Ivoire, Cameroon, Peru, and Zambia) according to the IFCPC classification (TZ1 = ectocervical fully visible; TZ2 = endocervical fully visible; TZ3 = not fully visible). Intra- and inter-observer agreement were measured by Fleiss’ kappa.ResultsOverall, 37.0% of images were interpreted as TZ1, 36.4% as TZ2, and 26.6% as TZ3. Global inter-observer reliability indicated fair agreement in both rounds (kappa 0.313 and 0.288). The inter-observer agreement was moderate for TZ1 interpretation (0.460), slight for TZ2 (0.153), and fair for TZ3 (0.329). Intra-observer analysis showed fair agreement for two observers (0.356 and 0.345), moderate agreement for two other (0.562 and 0.549), and one with substantial agreement (0.728).ConclusionInterpretation of the TZ using the IFCPC classification, adopted by the World Health Organization, is critical for determining if VIA screening and thermal ablation treatment are possible. However, the low inter- and intra-observer agreement suggest that the reliability of the referred classification is limited in the context of VIA. It’s integration in treatment recommendations should be used with caution since TZ3 interpretation could lead to an important referral rate for further evaluation.Trial registration Cantonal Ethics Board of Geneva, Switzerland: N°2017–0110. Cameroonian National Ethics Committee for Human Health Research N°2018/07/1083/CE/CNERSH/SP.

Expert recommendation on image-guided irreversible electroporation ablation treatment for renal carcinoma (2023 edition)

Irreversible electroporation ablation therapy can destroy tumor cells while retaining the integrity of the important surrounding physiological structures. It is suitable for patients with renal cell carcinoma who cannot be surgically resected or who do not want surgical resection, and can ensure the best postoperative renal function to the greatest extent, and has advantages that other thermal ablation treatments do not have. However, since irreversible electroporation therapy has high requirements for electrode needles and parameter settings, improper operation will directly affect the prognosis of patients. In order to improve the level of comprehensive treatment of renal cell cancer and standardize the operation technique of irreversible electroporation for renal cell carcinoma, the Committee of interventional minimally invasive therapy of the Chinese Medical Education Association took the lead in formulating the Expert Recommendation on image-guided irreversible electroporation ablation for Renal Cancer (2022 edition). The article introduces in detail the indications, contraindications, perioperative preparation, basic principles of operation, complications and related management and follow-up of irreversible electroporation for renal cell carcinoma, in order to provide reference for clinical practice.

Fiber Bragg Gratings for Temperature Measurements Under Thermal Gradients: Comparison Between Two Different Lengths

In recent decades, fiber Bragg grating (FBG) sensors found widespread acceptance in several biomedical applications thanks to their indisputable advantages. Thermal ablation treatments (TATs) account for one of the fields where FBGs have gained large applicability for temperature measurements. The sensing element length can affect the accuracy of the FBG measurement in this application. A longer length provides a more prominent peak in the FBG reflected spectrum, resulting in a higher signal-to-noise ratio (SNR). A shorter FBG length implies a lower SNR but offers the benefits of better spatial resolution. Therefore, the choice of an adequate length can be crucial to minimize measurement errors, but the literature lacks exhaustive investigations on this parameter. The aim of our study is to supply additional knowledge about the effect of two different FBG lengths on temperature estimation in the presence of linear thermal gradients and with gradients mimicking the condition caused by TATs. In both cases, we compared the output of a 10-mm FBG with those of four FBGs 1 mm long, using a thermal camera as a reference instrument. Results suggest the better suitability of shorter sensors to retrieve thermal gradient information along their position instead of the longer FBG, which could lead to unacceptable measurement errors during TATs.

A Systemic Study on the Performance of Different Quantitative Ultrasound Imaging Techniques for Microwave Ablation Monitoring of Liver

Many quantitative ultrasound imaging techniques based on tissue properties have been established to ensure the safety and efficacy of thermal ablation treatment. However, which quantitative ultrasound imaging technique has superior monitoring properties has not yet been revealed. In this study, we investigated and compared the performance of envelope data distribution-dependent ultrasonic Nakagami, envelope data distribution-independent horizontally normalized Shannon entropy (hNSE), and differential attenuation coefficient intercept (DACI) based on frequency domain imaging technique during liver thermal ablation treatments. Quantitative ultrasound parameter images were constructed simultaneously from radiofrequency (RF) data collected during the process of microwave ablation (MWA) treatments in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ex vivo</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in vivo</i> porcine livers. Contrast-to-noise ratios (CNR) were calculated to evaluate the contrast resolution of different imaging techniques. The mean CNR value of hNSE images was 6.06 ± 2.34 dB, being significantly higher than that of Nakagami images ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i> <0.05, statistical) and DACI images ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i> <0.05, statistical). Furthermore, the receiver operating characteristic (ROC) was used to evaluate the thermal lesion detection ability. The area under the curve (AUC) of B-mode, Nakagami, hNSE and DACI was 0.823, 0.839, 0.86 and 0.825, respectively. Additionally, our data analysis exhibited that hNSE has the excellent property of ablation area detections in the present study, whose correlation coefficient is 0.91. In conclusion, our study suggests that hNSE imaging, which does not require the specific data distribution has the best performance in thermal ablation detections and is a promising imaging method for further clinical research and application.

Design Under Uncertainties of the Thermal Ablation Treatment of Skin Cancer

Abstract This computational work deals with the optimal design of the thermal ablation treatment of skin cancer, by considering uncertainties in the model parameters. The tumor and other tissues were heated by a laser. Nanoparticles were used to improve the effects of the heating procedure and to promote thermal damage localized in the region containing the tumor. Treatment protocols examined in this work involved one single heating session with different prespecified durations, where the design variables were considered as the volume fraction of nanoparticles in the epidermis and tumor, as well as the time variation of the incident laser fluence rate. The optimal design problems were solved with the Markov Chain Monte Carlo method, by applying a modified version of the Metropolis-Hastings algorithm with sampling by blocks of parameters. The two parameter blocks were given by the properties of the tissues and by the design variables. The prior for the volume fraction of nanoparticles was given by a truncated Gaussian distribution, while a noninformative Gaussian Markov random field prior was used for the time variation of the laser fluence rate. The posterior distributions of the design variables were estimated by taking into account uncertainties in the model parameters and the desired statistical distribution of the thermal damage in the region of interest. The stochastic simulations resulted in optimal thermal damages with small uncertainties, which closely followed their desired statistical distribution functions.

Deep-learning based insitu ultrasound thermometry for thermal ablation monitoring

Noninvasive in situ temperature measurement (thermometry) is an attractive means of mapping the region of thermal damage during thermal ablation treatments. Existing methods of ultrasound thermometry are ineffective beyond 50 °C due to multiple physical limitations, including a non-monotonic relationship between temperature and sound speed that reaches a plateau around 60 °C, tissue phase transitions and deformation. An ultrasound-based technology that can monitor treatment over the entire therapeutic temperature range is desirable clinically. This paper describes a deep learning-based approach that uses thermometry data from the periphery of the heating zone (where temperatures are less than 50 °C) to infer temperature throughout the treatment zone. Spatiotemporal 2D temperature maps from 3–12 s HIFU heating exposures (in 0.5 s increments) were generated (using COMSOL) with a subset used for training the network and the rest for testing. Peripheral temperature values (excluding the first 5 mm closest to the axial focus), scalar time values, and a binary flag indicating heating/cooling were inputs to the network, and the temperature profile axially through the HIFU focus was predicted. The temperature prediction accuracy was better than 0.5 °C during heating and cooling. This paper will also address robustness to noise in the input temperature measurements and discuss future directions including experiments with ultrasound backscatter data and strategies to explicitly incorporate heat diffusion physics into the learning paradigm.

Meta-Analysis of the Application Effect of Different Modalities of Thermal Ablation and Surgical Treatment in Papillary Thyroid Microcarcinoma.

Background Papillary thyroid microcarcinoma (PTMC) refers to papillary thyroid carcinoma (PTC) with a maximum diameter of 10 mm. Thermal ablation, including radiofrequency ablation (RFA), microwave ablation (MWA), and laser ablation (LA), has been applied in the treatment of benign thyroid nodules and captured extensive attention. At present, the application of thermal ablation in PTMC has been extensively reported, but outcomes such as volume reduction rate (VRR), complete remission rate (CRR), and adverse reaction rate (ARR) vary considerably. Therefore, this meta-analysis was performed to evaluate the safety and efficacy of different treatment methods of PTMC. Methods We did a systematic review and network meta-analysis. We searched PubMed, EMBase, and Cochrane-Library from the date of inception to January 10, 2022, to retrieve the VRR, CRR, and ARR of MWA, RFA, LA and surgical treatment of PTMC, and a meta-analysis was performed using the R meta-package. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated, and sensitivity analyses, cumulative meta-analyses, and publication bias were also performed. Relevant literature was retrieved with keywords; the eligible cohort studies were screened based on the established inclusion and exclusion criteria. Results A total of 1515 patients were included in the 12-month follow-up. The overall VRR was 86.25% (95% CI: 77.89, 94.60), and the VRR was RFA > WMA > LA, but the differences were not significant. A total of 1483 patients were included in the last follow-up. The overall VRR was 99.41% (95% CI: 99.11, 99.72), and the VRR was RFA > WMA > LA, but the differences were not significant. A total of 1622 patients showed complete remission at the last follow-up, and the overall CRR was 0.63 (95% CI: 0.46, 0.79). The CRR was RFA > LA > WMA, but the differences were not significant. A total of 1883 patients had adverse reactions at the last follow-up, and the overall ARR was 0.06 (95% CI: 0.03, 0.08). The ARR at the last follow-up was RFA = Surg < LA < WMA. The ARR of the RFA and Surg subgroups was significantly lower than that of the WMA subgroup. Conclusions Similar good efficacy and safety profiles were observed in WMA, RFA, LA, and surgical treatment in PTMC, among which RFA showed the best volume reduction, complete remission rate, and adverse reaction reduction. However, there is a slight bias in the limited literature included in this study, and we did not conduct or refer to mechanistic studies to confirm its specific mechanism of action. Clinicians are advised to use their discretion in the choice of treatment.

Evolution of a theranostic applicator for microwave ablation treatment

Abstract The purpose of this work is to further develop a novel dual-mode microwave applicator for diagnosis and thermal ablation treatment. The MR-compatible MW applicator enables differentiation of tumor tissue and healthy tissue through dielectric contrast measurements, optimizing the positioning of the applicator in the lesion. Due to the robust applicator design and the resulting permittivity tracking during ablation, even carbonized tissue can be detected. The use of operating frequencies between 5 and 10 GHz allow a noticeably lower power consumption for microwave ablation of only 20 W compared to commercially available applicators. Clinically relevant dimensions of ablation zones can be achieved and additionally monitored using MR imaging and thermometry.

Ultrasound Entropy Imaging for Detection and Monitoring of Thermal Lesion During Microwave Ablation of Liver.

Ultrasonic B-mode imaging offers non-invasive and real-time monitoring of thermal ablation treatment in clinical use, however it faces challenges of moderate lesion-normal contrast and detection accuracy. Quantitative ultrasound imaging techniques have been proposed as promising tools to evaluate the microstructure of ablated tissue. In this study, we introduced Shannon entropy, a non-model based statistical measurement of disorder, to quantitatively detect and monitor microwave-induced ablation in porcine livers. Performance of typical Shannon entropy (TSE), weighted Shannon entropy (WSE), and horizontally normalized Shannon entropy (hNSE) were explored and compared with conventional B-mode imaging. TSE estimated from non-normalized probability distribution histograms was found to have insufficient discernibility of different disorder of data. WSE that improves from TSE by adding signal amplitudes as weights obtained area under receiver operating characteristic (AUROC) curve of 0.895, whereas it underestimated the periphery of lesion region. hNSE provided superior ablated area prediction with the correlation coefficient of 0.90 against ground truth, AUROC of 0.868, and remarkable lesion-normal contrast with contrast-to-noise ratio of 5.86 which was significantly higher than other imaging methods. Data distributions shown in horizontally normalized probability distribution histograms indicated that the disorder of backscattered envelope signal from ablated region increased as treatment went on. These findings suggest that hNSE imaging could be a promising technique to assist ultrasound guided percutaneous thermal ablation.

Highly Exfoliated N-Doped Reduced Graphene Oxide Derivatives Synthesis and Application

Carbon-based nanomaterials such as graphene, graphene oxide, carbon nanotubes, graphene nanoribbons, etc. are considered as promising materials for energy storage and conversion, electrode sensing, optical and electronic applications. High specific surface area, porosity, and chemical modifications are some of the most important factors for tailoring the (electro)chemical, physical, and mechanical properties of graphene derivatives.1 Nitrogen-doped graphene derivatives have been identified as promising materials for energy storage and conversion2 and sensing applications. One of the most common syntheses of N-doped graphene derivatives is the N-doping of graphene oxide prepared by the Hummers method. The methods for simultaneous N-doping and reduction of graphene oxide are diverse: thermal annealing, pyrolysis, solvothermal, laser ablation, microwave-assisted, and hydrazine treatment.1 However, the above methods yield N-doped graphene derivatives, which are usually poorly exfoliated and have a low specific surface area. Therefore, an efficient strategy to improve the specific surface area of N-doped graphene oxide derivatives needs to be developed.3 Herein we present a new "induction heating method" for the preparation of N-doped reduced graphene oxide derivatives (N-rGOD) with a high specific surface area. N-rGOD was prepared in a two-step process from commercially available graphites (Gs) and multi-walled carbon nanotubes (MWCNTs). In the first step, graphite oxide precursors were synthesized from Gs or MWCNTs by the improved Hummers method. In the second step, the graphite oxide precursors were subjected to rapid heat treatment by induction heating in a reductive ammonia atmosphere. Due to the rapid thermal expansion of graphite oxide, massive exfoliation occurred to obtain N-rGOD with higher specific surface area.4 These materials were tested for energy storage and conversion applications and showed excellent properties. References (1) Xu, H.; Ma, L.; Jin, Z. Nitrogen-Doped Graphene: Synthesis, Characterizations and Energy Applications. J. Energy Chem. 2018, 27 (1), 146–160. https://doi.org/10.1016/j.jechem.2017.12.006.(2) Nosan, M.; Löffler, M.; Jerman, I.; Kolar, M.; Katsounaros, I.; Genorio, B. Understanding the Oxygen Reduction Reaction Activity of Quasi-1D and 2D N-Doped Heat-Treated Graphene Oxide Catalysts with Inherent Metal Impurities. ACS Appl. Energy Mater. 2021. https://doi.org/10.1021/acsaem.1c00026.(3) Alazmi, A.; El Tall, O.; Rasul, S.; Hedhili, M. N.; Patole, S. P.; Costa, P. M. F. J. A Process to Enhance the Specific Surface Area and Capacitance of Hydrothermally Reduced Graphene Oxide. Nanoscale 2016, 8 (41), 17782–17787. https://doi.org/10.1039/c6nr04426c.(4) Qiu, Y.; Guo, F.; Hurt, R.; Külaots, I. Explosive Thermal Reduction of Graphene Oxide-Based Materials: Mechanism and Safety Implications. Carbon N. Y. 2014, 72, 215–223. https://doi.org/10.1016/j.carbon.2014.02.005.

Study of heat sink effect of blood in a bifurcated vessel

Thermal ablation treatment uses elevated (hyperthermia) or depressed (hypothermia) tissue temperature to destroy tumor cells. The efficacy and effectiveness of thermal ablation therapy is dependent on the tissue temperature which is significantly affected due to heat sink effect of blood flow near the infected site. In this study, Euler-Euler multiphase model is used to analyze the effect of plasma and RBC concentration on the heat sink effect of blood in a bifurcated vessel. This study is divided into two separate cases. First case refers to the study of heat sink effect produced by a tumor patient suffering from HVS (hyperviscosity syndrome) and a normal (without blood disorder) tumor patient during hyperthermia treatment. The second case analyses the effect of RBCs on blood heat transfer. Temperature distribution and transient Nusselt number, which are used to represent heat sink effect, are calculated and compared for different cases of blood disorders. From the results, it is found that a patient with HVS blood disorder produces a smaller heat sink effect during hyperthermia treatment compared to a normal tumor patient. Also, the level of RBC concentration in the blood stream has a minimal effect on heat transfer.

Complications Risk Assessment and Imaging Findings of Thermal Ablation Treatment in Liver Cancers: What the Radiologist Should Expect.

One of the major fields of application of ablation treatment is liver tumors. With respect to HCC, ablation treatments are considered as upfront treatments in patients with early-stage disease, while in colorectal liver metastases (CLM), they can be employed as an upfront treatment or in association with surgical resection. The main prognostic feature of ablation is the tumor size, since the goal of the treatment is the necrosis of all viable tumor tissue with an adequate tumor-free margin. Radiofrequency ablation (RFA) and microwave ablation (MWA) are the most employed ablation techniques. Ablation therapies in HCC and liver metastases have presented a challenge to radiologists, who need to assess response to determine complication-related treatment. Complications, defined as any unexpected variation from a procedural course, and adverse events, defined as any actual or potential injury related to the treatment, could occur either during the procedure or afterwards. To date, RFA and MWA have shown no statistically significant differences in mortality rates or major or minor complications. To reduce the rate of major complications, patient selection and risk assessment are essential. To determine the right cost-benefit ratio for the ablation method to be used, it is necessary to identify patients at high risk of infections, coagulation disorders and previous abdominal surgery interventions. Based on risk assessment, during the procedure as part of surveillance, the radiologists should pay attention to several complications, such as vascular, biliary, mechanical and infectious. Multiphase CT is an imaging tool chosen in emergency settings. The radiologist should report technical success, treatment efficacy, and complications. The complications should be assessed according to well-defined classification systems, and these complications should be categorized consistently according to severity and time of occurrence.

Risk factors of residual tumor in single small hepatocellular carcinoma after thermal ablation treatment

Objective: To evaluate the risk factors of residual tumor after thermal ablation in patients with small hepatocellular carcinoma. Methods: This was a retrospective study recruiting 107 patients diagnosed as single hepatocellular carcinoma with maximum diameter ≤3 cm from December 2009 to August 2015 in National Cancer Center. The cohort enrolled 81 males and 26 females, including 83 patients younger than 70 years old. All patients were treated with radiofrequency ablation or microwave ablation, and evaluated by CT or MRI after 4-6 weeks compared with baseline data. Potentially related factors were analyzed such as patients' characteristics, tumor location and adjacent, ablation pattern, hepatitis B/C infection. A multivariate logistic regression analysis was conducted for the independence of risk factors. Results: Six patients (5.6%) with residual tumor was detected in the whole population of 101 cases. Univariate analysis suggested that tumor adjacent to vascular structure, poor differentiation, AFP≥200 μg/L were the risk factors of residue disease (all P<0.05). Multivariate logistic regression suggested that pathological type of poorly differentiated tumor was the only independent risk factor (HR=2.26,95%CI 0.25-20.50, P=0.030). Conclusions: Poorly differentiated pathology is an independent predictive factor for residual disease in small hepatocellular carcinoma after thermal ablation. Such patients should be routinely followed up after operation.

Efficacy of Thermal Ablation for Treatment of High-Grade Cervical Dysplasia Among HIV-Positive Women: Preliminary Results From Western Kenya

PURPOSE In 2019, the World Health Organization (WHO) endorsed thermal ablation (TA) for use within “screen-and-treat” cervical cancer prevention programs in low- and middle-income countries (LMICs), including among women living with HIV (WLWH). We evaluated TA efficacy for treatment of biopsy-confirmed cervical intraepithelial neoplasia grades 2 and 3 (CIN2/3) among WLWH in western Kenya (ClinicalTrials.gov NCT04191967). METHODS Between August 2019 and November 2020, WLWH age 25-65 years underwent high-risk human papillomavirus (hrHPV) self-collection. hrHPV-positive women underwent colposcopy-directed biopsies, and thermal ablation treatment if eligible per WHO guidelines. Women with biopsy-confirmed CIN2/3 had colposcopy-directed biopsies at 12-months to determine treatment efficacy. RESULTS Sixty-eight hrHPV-positive WLWH with biopsy-confirmed CIN2/3 at baseline; 14 CIN2, 54 CIN3, underwent thermal ablation. Mean age and parity were 41.2 years and 4, respectively. The mean CD4 count was 473.98 cells/mm3 and 96.9% had HIV viral suppression. Fifty-eight women (83.8%) have been seen for a 12-month follow-up visit, and pathology results are available for 54 (79.4%). Of these, 35 (66.0%) had successful treatment, defined as biopsy-confirmed CIN1 or normal findings 12-months following treatment, while 18 (34.0%) had treatment failure - persistent biopsy-confirmed CIN2/3. Treatment failure was 23.1% 95% CI (13.0 to 45.9) and 37.5%, 95% CI (22.1 to 52.0) among women with CIN2 and CIN3 at baseline, respectively. CONCLUSION Hand-held thermal ablation devices are affordable, portable, easy to use, and hence highly scaleable within screen-and-treat programs in LMICs. However, our preliminary results, with rigorous disease status verification at both baseline and follow-up find higher than previously reported treatment failure rates for CIN3 among WLWH, a high-risk population for cervical cancer. If replicated by larger studies, this highlights a potential limitation of the current WHO cervical cancer elimination strategy, calling for better risk stratification in this population, and/or consideration of adjuvant therapy to prevent CIN2/3 recurrence following thermal ablation.

Efficacy and safety of endovenous microwave ablation versus laser ablation for great saphenous vein varicosis: study protocol for a multicentre, randomised controlled non-inferiority trial

IntroductionEndovenous microwave ablation (EMA) is a relatively novel thermal ablation treatment for great saphenous vein (GSV) varicosis, and its efficacy and safety are rarely reported. This study aims to explore...

A computational framework to simulate the thermochemical process during thermochemical ablation of biological tissues

Thermochemical ablation (TCA) is a thermal ablation therapy that utilises heat released from acid-base neutralisation reaction to destroy tumours. This procedure is a promising low-cost solution to existing thermal ablation treatments such as radiofrequency ablation (RFA) and microwave ablation (MWA). Studies have demonstrated that TCA can produce thermal damage that is on par with RFA and MWA when employed properly. Nevertheless, TCA remains a concept that is tested only in a few animal trials due to the risks involved as the result of uncontrolled infusion and incomplete acid-base reaction. In this study, a computational framework that simulates the thermochemical process of TCA is developed. The proposed framework consists of three physics, namely chemical flow, neutralisation reaction and heat transfer. An important parameter in the TCA framework is the neutralisation reaction rate constant, which has values in the order of 108 m3/(mol⋅s). The present study will demonstrate that since the rate constant impacts only the rate and direction of the reaction but has little influence on the extent of reaction, it is possible to replicate the thermochemical process of TCA by employing significantly smaller values of rate constant that are numerically tractable. Comparisons of the numerical results against experimental studies from the literature supports this. The aim of this framework is for researchers to advance and develop TCA to gain an in-depth understanding of the fundamental mechanisms of TCA and to develop a safe treatment protocol of TCA in the hope of advancing TCA into clinical trials.