Efficacy and safety of microwave ablation for benign thyroid nodules: a Meta-analysis

Objective To compare the application of ultrasound-guided radiofrequency ablation (RFA) and minimally invasive endoscopic surgery in the treatment of patients with benign thyroid nodules. Methods From January 2015 to January 2019, one thousand patients with benign thyroid nodules who underwent surgery in the 928th Hospital of Chinese People’s Liberation Army Joint Logistics and Support Force were divided into ultrasound-guided RFA group (594 cases) and minimally invasive endoscopic surgery group (406 cases) according to different surgical methods. The operation time, intraoperative blood loss, postoperative hospitalization time, changes of thyroid function before surgery and 6 months after surgery, interleukin-6 (IL-6), C-reactive protein (CRP), tumor necrosis factor α (TNF-α), and occurrence of postoperative complications were compared between the two groups. Results After surgery, levels of IL-6, CRP and TNF-α in RFA group were significantly lower than those in minimally invasive endoscopic surgery group (t=-67.827, -117.340, 32.192, all P<0.001). The operation time, postoperative hospitalization time, surgical blood loss, and the incidence of postoperative complications in RFA group were significantly lower than those in minimally invasive endoscopic surgery group (t=85.135, 67.418, 65.475, χ2=169.568, all P<0.001). Conclusions The damage of both ultrasound-guided RFA and minimally invasive endoscopic surgery in treatment of patients with benign thyroid nodules is relatively less for thyroid function. The safety of the former is better, with less trauma and fewer postoperative complications. Key words: Thyroid nodule; Catheter ablation; Ablation techniques; Surgical procedures, minimally invasive

Objective: To investigate the efficacy of ultrasound-guided microwave ablation (MWA) for benign thyroid nodules and to analyze the correlation between treatment outcomes and various influencing factors. Methods: 95 patients with pathologically confirmed benign thyroid nodules（ totally 96 nodules) who underwent MWA under ultrasound guidance were enrolled in this retrospective study. Pre-ablation and post-ablation follow-up examinations including two-dimensional ultrasound, color Doppler, and contrast-enhanced ultrasound were conducted at 1, 3, and 6 months. The clinical efficacy was assessed, including the reduction in nodule volume and the success rate of ablation. Factors that might influence treatment outcomes, such as patient age, gender, nodule size, type, and ablation parameters, were analyzed. Statistical correlations were evaluated using Spearman’s correlation coefficient and multiple regression analysis. Results: MWA has demonstrated favorable efficacy in treating benign thyroid nodules, with a low incidence of complications. Most nodules experienced significant volume reduction or even complete disappearance after treatment (P &lt; 0.05). The average volume reduction ratio (VRR) of benign thyroid nodules undergoing MWA at 1 month, 3 months, and 6 months post-operation were 52.98%±22.23%, 68.18%±19.81%, and 82.39%±15.03%, respectively, with a significant reduction rate (VRR &gt; 50%) observed in 95.8% (92/96) of the nodules (VRR &gt; 50%). Cystic nodules exhibited the most substantial volume reduction following ablation. The initial volume of the nodule, blood flow status, nodule composition, and the energy absorption per unit volume were all related to the postoperative VRR (P &lt; 0.05). Factors such as patient age, gender, and ablation duration did not show significant correlation with ablation efficacy (P＞0.05). Conclusion: MWA is a promising minimally invasive treatment for benign thyroid nodules. The treatment efficacy is closely related to the initial volume of the thyroid nodule, the composition of the nodule, the blood flow situation of the nodule, and the ablation energy per unit volume.

To evaluate the therapeutic efficacy and safety of ultrasound-guided percutaneous bipolar radiofrequency ablation (BRFA) of benign thyroid nodules by comparison with a matched untreated control group. The therapeutic efficacy and safety in 35 patients who were subjected to a single session of ultrasound-guided percutaneous BRFA (Group A) for benign thyroid nodules were compared with those in 35 untreated patients (Group B) with benign nodules. The benign nature of all the nodules was confirmed by ultrasound-guided fine-needle aspiration biopsy (FNAB), and all the patients had normal thyroid functions. BRFA was performed with a bipolar electrode (CelonProSurge 150-T20) with an output power of 20 W. Nodule volume, thyroid function and clinical symptoms of all the patients were compared before treatment and during follow-up. In Group A, the BRFA procedures were completed with a mean time of 10.02 ± 3.30 min (range, 5.47-16.03 min) and with a mean total energy deposition of 10.747 ± 3704 J (range, 5510-17.770 J). The procedures were tolerated well in all the patients without causing any major complications. At the 6-month follow-up, all of the nodule volume decreased significantly (from 8.81 ± 8.66 to 1.59 ± 1.55 ml, p < 0.001) in Group A, whereas the nodule volume increased from 6.90 ± 3.77 to 7.87 ± 3.95 ml in Group B (p < 0.001). All (100%) the 35 nodules in Group A had volume reduction ratios (VRRs) of >50%, among which 3 (8.57%) had VRRs >90%. In Group A, the clinical symptoms of the patients who had symptoms before BRFA disappeared, whereas in Group B, the patients had no resolution of clinical symptoms at the 6-month follow-up. Ultrasound-guided percutaneous BRFA seems to be an effective and safe method for the treatment of benign thyroid nodules. It may gain a wide use in clinical practice. Based on the comparable efficacy and clinical symptoms between the BRFA and untreated groups, the technique of BRFA can be used as an effective and safe method for the treatment of benign thyroid nodules.

Objective: To compare the short-term efficacy and the safety of microwave ablation (MWA) and radiofrequency ablation (RFA) in the treatment of benign thyroid nodules (BTNs). Methods: This prospective randomized controlled trial, performed from December 2019 to September 2021, included 36 patients with solid or predominantly solid BTNs who met the eligibility criteria and provided written informed consent at the Nanjing sub-center (Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine). Patients were assigned to either the MWA group or the RFA group (18 patients in each group) at a ratio of 1∶1 using a block randomization design and allocation concealment using sealed envelope randomization. The independent-sample t-test and χ2 test were used to compare the volume reduction rates (VRRs), effective rates (VRRs≥50%), cosmetic scores, and complication rates at 1, 3, and 6 months after treatment between the two groups. Results: The clinical characteristics of the two groups of patients were comparable. After ablation, the nodule volume was significantly reduced in both groups. At 1, 3, and 6 months, there was no significant difference in the volume between the two groups (all P>0.05). At 3 months, the RFA group had a larger VRRs than that in the MWA group (62.08%±12.46% vs. 46.90%±23.16%, t=-2.45, P=0.021). However, at 1 and 6 months, no statistical significance was observed (both P>0.05). No significant difference was observed in the effective rates at the last follow-up (14/18 vs. 18/18, P=0.104). However, the RFA group had a lower cosmetic score than that in the MWA group (1.78±0.43 vs. 2.17±0.51, t=-2.47, P=0.019). There was no statistically significant difference in the complication rates between the two groups (all P>0.05). Conclusions: Both MWA and RFA were effective and safe treatments for BTNs, with no significant differences in short-term efficacy and safety. In addition, the RFA group showed slightly more favorable outcomes than the MWA group in terms of cosmetic improvement.

BackgroundLarge benign thyroid nodules often lead to cosmetic problems and compression on trachea. Thermal ablation is an effective method for benign thyroid nodules treatment. Among all the thermal ablation techniques, microwave and radiofrequency are frequently used energy sources. However, treatment outcomes of the two ablation types have not been compared in detail. Therefore, we conducted this study aiming for comparing the safety and efficacy of the two ablation techniques in benign thyroid nodules treatment.MethodsInformation was retrospectively collected from patients with benign thyroid nodules, who received radiofrequency ablation or microwave ablation between January 1, 2018, and December 31, 2019, in a main hospital in South China. Patients were divided into microwave ablation group and radiofrequency ablation group according to the techniques applied. A propensity score matching was performed to balance the baseline indexes between the two groups. We also recorded and analyzed the operative variables including operative duration, intraoperative blood loss, hospitalization time, and overall costs. Postoperative quality of life, volume reduction rates, and complication rates were routinely evaluated during the follow-up by asking patients to fulfil questionnaires at the 1st, 3rd, 6th, 12th, and 18th postoperative month.ResultsA total of 943 patients receiving microwave ablation or radiofrequency ablation in the years of 2018 and 2019 met our inclusion criteria. After 1:1 propensity score matching, 289 pairs of patients were matched. There was no significant difference between the two groups in operative duration, intraoperative blood loss, hospitalization time, overall cost, quality of life scores, complication rates or volume reduction rates.ConclusionThere was no significant difference between microwave and radiofrequency ablation in terms of safety and efficacy. Both of the two techniques` are ideal therapeutic methods in benign thyroid nodules treatment.Registration numberChiCTR2000034764.

BackgroundUltrasound-guided thermal ablations have become one of the main options for treating benign thyroid nodules. To determine efficacy of thermal ablation of benign thyroid nodules, we performed a meta-analysis of studies with long-term follow-up of more than 3 years.MethodsDatabases were searched for studies published up to August 25, 2019, reporting patients with benign thyroid nodules treated with thermal ablation and with follow-up data of more than 3 years. Data extraction and quality assessment were performed according to PRISMA guidelines. The analysis yielded serial volume reduction rates (VRRs) of ablated nodules for up to 3 years or more, and adverse effect of ablation during follow-up. Radiofrequency ablation (RFA) and laser ablation (LA) were compared in a subgroup analysis.ResultsThe pooled VRRs for ablated nodules showed rapid volume reduction before 12 months, a plateau from 12 to 36 months, and more volume reduction appearing after 36 months, demonstrating long-term maintenance of treatment efficacy. Thermal ablation had an acceptable complication rate of 3.8%. Moreover, patients undergoing nodule ablation showed no unexpected delayed complications during the follow-up period. In the subgroup analysis, RFA was shown to be superior to LA in terms of the pooled VRR and the number of patients who underwent delayed surgery.ConclusionThermal ablations are safe and effective methods for treating benign thyroid nodules, as shown by a long follow-up analysis of more than 3 years. In addition, RFA showed superior VRRs compared with LA for the treatment of benign thyroid nodules, with less regrowth and less delayed surgery.

Microwave ablation (MWA) is a novel modality for thermal ablation (TA) to treat benign and malignant thyroid nodules, mostly papillary thyroid cancer (PTC). Compared to surgery, TA is less invasive and less painful, has faster recovery, better cosmetic outcomes, and fewer complications. TA techniques have been evolving over the past decade to be more energy efficient, precise, and produce long-lasting results. The general approach is similar between various TA techniques. However, each technique has uniqueness in its energy delivery and, thus, risk profile and outcomes. MWA has a few critical technical differences that make it safer for patients with surgical implants and cardiac comorbidities. It has proven effective in treating benign thyroid nodules (BTNs) in adults and pediatric populations with benign and malignant lesions. The clinical and theoretical outcomes of MWA compared to other thermal ablative techniques, such as radiofrequency ablation (RFA) and laser ablation (LA), have been investigated in some studies and meta-analyses. Minimally invasive procedures such as MWA are an important tool for the management of thyroid lesions. Thus, it is crucial for clinicians to be equipped with the knowledge to use these tools. In this review, we provide a clinical review detailing the technical differences and clinical outcomes for the three major TA techniques-MWA, RFA, and LA.

The objective of the present study was to investigate the effectiveness and safety of ultrasound-guided microwave ablation in the treatment of benign thyroid nodules. A total of 474 benign thyroid nodules in 435 patients who underwent ultrasound-guided microwave ablation from September 2012 to August 2015 were included. Nodule volume and thyroid function were measured before treatment and at 1, 3, 6, and 12 months and subsequently after every 6 months. The nodule volume reduction rate and changes of thyroid function were evaluated. The volume of all thyroid nodules significantly decreased after ultrasound-guided microwave ablation. The average volume was 13.07 ± 0.95 ml before treatment, and 1.14 ± 0.26 ml at 12-months follow-up. The mean volume reduction rate was 90% and the final volume reduction rate was 94%. The volume reduction rate of mainly cystic nodules was significantly higher than that of simple solid and mainly solid nodules (all P < 0.05). The pretreatment volume of nodules was positively correlated with the final volume reduction rate at final follow-up ( P = 0.004). No serious complications were observed after treatment. In conclusion, ultrasound-guided microwave ablation is an effective and safe technique for treatment of benign thyroid nodules, and has the potential for clinical applications. Impact statement Ultrasound-guided MWA is an effective and safe technique for the treatment of benign thyroid nodules. It can significantly reduce the nodule volume, improve the patients' clinical symptoms, has less complication, guarantees quick recovery, meets patients' aesthetic needs, and shows less interference on the physiological and psychological aspects of the body. MWA should be a good complement to traditional open surgery and has potentials in clinical applications.

Background: The efficacy and safety of radiofrequency ablation (RFA) and microwave ablation (MWA) in treating benign thyroid nodules (BTNs) remains unclear.This study was aimed to compare the efficacy and safety of RFA and MWA in treating BTNs.Methods: A systematic search of PubMed, Embase, and Cochrane databases was conducted up to September 11, 2023, to identify relevant studies.The primary outcomes included volume reduction rate (VRR), symptomatic and cosmetic scores analyzed using standardized mean difference (SMD), and complications assessed by risk difference (RD).Results: A meta-analysis of five eligible studies demonstrated that RFA and MWA had comparable pooled 3-month and 6-month VRRs (56.0% vs. 53.9%,p = .668;80.8% vs. 74.9%,p = .080).However, RFA exhibited a significantly higher VRR than MWA after 12 months (86.2% vs. 80.0%, p = .036).Furthermore, both RFA and MWA showed significant reductions in pooled symptomatic and cosmetic scores over time, with no statistically significant differences between the two groups at 6 and 12 months.Additionally, there were no significant differences in the incidence of major or minor complications between RFA and MWA.Conclusion: The meta-analysis indicates that both RFA and MWA are effective and relatively safe treatments for BTNs, with RFA potentially offering a slight advantage in long-term volume reduction.Nevertheless, further research is warranted to validate these findings and determine the optimal treatment strategy for BTNs.

Benign thyroid nodules are common and may cause compressive symptoms, cosmetic concerns, or hyperthyroidism. Ultrasound (US)-guided thermal ablation has emerged as a minimally invasive alternative to surgery. This study aimed to evaluate the efficacy and safety of surgeon-performed US-guided microwave ablation (MWA) for benign thyroid nodules. A retrospective analysis of prospectively collected data was performed on 32 patients who underwent US-guided MWA between May 2023 and May 2024. All procedures were performed by a single surgeon. Nodule volume, volume reduction ratio (VRR), thyroid function tests, and complications were evaluated at baseline and at 6- and 12-month follow-up. Technical success was defined as VRR >50% at 12 months. The mean baseline nodule volume was 17.73±11.70cm3, which decreased significantly to 7.40±4.92cm3 at 6 months and to 2.31±1.61cm3 at 12 months (P<0.001). Mean VRR was 58.5% at 6 months and 87.1% at 12 months, with technical success achieved in all patients. VRR was not significantly affected by nodule composition, size, vascularity, or location. Among 3 patients with toxic adenoma, euthyroidism was achieved in 2 patients with complete discontinuation of antithyroid medications, while 1 patient improved from overt to subclinical hyperthyroidism with reduced medication dosage. No major complications were observed. Surgeon-performed US-guided MWA is a safe and highly effective minimally invasive treatment for benign thyroid nodules, providing substantial and durable volume reduction with excellent clinical outcomes in appropriately selected patients.

ObjectivesGiven that the histological features of the thyroid parenchyma in patients with Hashimoto's thyroiditis (HT) differ from those of the normal thyroid gland, HT may affect the effectiveness of ultrasound-guided microwave ablation (MWA) for benign thyroid nodules (BTNs). The present study aimed to compare the effectiveness of MWA for the treatment of BTNs in patients with both BTNs and HT and those with BTNs and normal thyroid function, based on changes in the volume reduction ratio (VRR) of the BTNs.MethodsPatients who had achieved a VRR ≥50% after MWA for BTN (July 2020–June 2021), followed up for 12 months, and their data were retrospectively analyzed.ResultsA total of 213 nodules were identified in 185 patients, including 167 in the “BTN” group and 46 in the “BTN + HT” group. A comparison of the fitting curves for VRR–follow-up time revealed that the VRR increased with time after MWA, although the relationship was nonlinear. Piece-wise linear regression model analysis of the threshold effect of VRR and follow-up time in the two groups indicated that the inflection point of the “BTN” group occurred at 2.1 months: VRR increased fastest within 2.1 months of MWA (rate of change: 32.9% per month; P < 0.001), following which the rate of change was slower and maintained at 1.0% per month (P = 0.006). In the “BTN + HT” group, the inflection point occurred 1.5 months after MWA, with the most significant increase occurring in this period (rate of change: 41.5% per month; P < 0.001), followed by a rate of 2.8% per month (P < 0.001) after 1.5 months.ConclusionsThe relationship between VRR and follow-up time for ultrasound-guided MWA for BTN is nonlinear and exhibits a threshold effect. The current results indicated that the VRR in both groups increased before and after the inflection point, although the rate of change was greater before than after the inflection point. The inflection point occurs earlier in patients with BTN + HT than in those with BTN yet normal thyroid function, and this difference may be related to the “oven effect” involved in the development of HT.

To evaluate the efficacy and safety of radiofrequency ablation (RFA) for benign nonfunctional thyroid nodules or functional lingual thyroid gland in a pediatric population. Four pediatric patients (four female; mean age 13.50 ± 4.04, range 8-17 years) with either benign thyroid nodules or mildly obstructive lingual thyroid glands were treated with RFA from 2020 to 2021 were evaluated. The inclusion criteria for RFA therapy were (i) age < 18 years; (ii) benign cytopathological results on ultrasound guided fine needle aspiration; (iii) pressure or pain symptoms caused by the thyroid nodules; (iv) dysphagia or obstruction caused by the lingual thyroid tissue; (v) follow up for >6 months with otolaryngology or endocrinology. Two patients had benign non-functioning thyroid nodules and two had mildly obstructive functioning lingual thyroid glands. Mean follow up was 10.75 ± 4.79 months. Each patient underwent one RFA session with no complications. For the patients with thyroid nodules, there was >74% reduction in nodule size at last follow up with improvement in neck swelling and pain. For the patients with lingual thyroid glands, both did not have any other functional thyroid gland identified. Both had visible decrease in size of the gland as visualized transorally with improvement in dysphagia and obstructive symptoms when lying flat. RFA is a safe and effective option for managing benign thyroid nodules and lingual thyroid glands in a pediatric patient population. 4.

To evaluate the safety and efficacy of microwave ablation (MWA) in treating benign thyroid nodules and any advantage of modified hydrodissection (MHD) techniques while performing these procedures. This retrospective study included 76 consecutive patients treated for benign thyroid nodules using MWA. Patients were divided into 2 groups. Group 1 included patients treated before November 2019 using the hydrodissection technique (n = 38), and group 2 included patients treated using the MHD technique after November 2019 (n = 38). Hydrodissection-MHD was performed using 5% dextrose. A portable MWA device with a 2450MHz frequency was used as the generator. MWA antennas with internal water-cooled units and temperature monitoring features with a 16G diameter, 100cm body length, and 3mm tip length were used for MWA procedures. Color Doppler ultrasound examinations, thyroid function tests, volume reduction ratios, Visual Analog Scales, and Cosmetic Scores were performed on the patients in the first, third, sixth, and every sixth months after ablation procedures. Complications and procedure times were also recorded. No significant differences in volume reduction ratios, Visual Analog Scale, or Cosmetic Score were observed between the groups at 3, 6, and 12 months. Lower complication rates ( 26.31% vs 7.89%, P = 0.03) and procedure times (10.30 vs 7.30 min; P = 0.04) were observed with the MHD technique. There were no residual or recurrent nodules or thyroid hormone deficiencies during the follow-up. MWA of benign thyroid nodules is safe and effective. Using the MHD technique lowers complication rates and procedure time.

Purpose To assess the feasibility, efficacy, and safety of ultrasound (US)-guided microwave ablation (MWA) for the treatment of papillary thyroid cancer (PTC) located in the thyroid isthmus. Materials and methods Thirty-four patients (mean age, 43 ± 11 years; 26 women) with isthmic PTC treated with MWA between June 2014 and September 2020 were included in this retrospective study. The follow-up time after MWA was 17 ± 9 months (range, 8–50 months). Changes in thyroid function, parathyroid function, and tumor size were evaluated, along with the rates of tumor disappearance and complications. Results The treatment was technically feasible and successfully completed in all 34 patients (100%). Measures of thyroid function (i.e. serum triiodothyronine, free thyroxine, and thyrotropin) and parathyroid function (i.e. serum calcium and intact parathyroid hormone) showed no changes from pretreatment levels at 1, 3, and 6 months after MWA (p > 0.05 for all). Tumor size was found to be increased at 1 and 3 months after MWA compared with before MWA (p < 0.05). However, the tumor sizes measured at 6, 9, 12, and 18 months after MWA were smaller than the pretreatment sizes (p < 0.05 for all). In 24 cases (70.6%), the tumors completely disappeared on US examination. Five cases (2.9%) experienced side effects from MWA treatment, but no major or minor complications were recorded. Conclusion The results of this study demonstrate that US-guided MWA is a feasible, effective, and safe treatment option for selected patients with PTC located in the thyroid isthmus.

The aim of the study was to compare the efficacy, procedural features, and safety profile of radiofrequency ablation (RFA) versus microwave ablation (MWA) for the treatment of non-functioning benign thyroid nodules (BTNs). This retrospective, single-centre, cohort study included 203 nodules treated with RFA and 71 with MWA by a single experienced operator. Multivariate linear regression analysis was performed to identify independent predictors of treatment response, defined as 12-month volume reduction rate (VRR). Complication rates were also compared between RFA and MWA. A 1:1 case-control matching was performed based on baseline nodule volume and composition, yielding two matched cohorts of 66 patients each. VRRs after 6 and 12 months were compared between two groups. In the overall population, similar VRRs were observed after 6 and 12 months. Significant differences in baseline nodule volume (24.35 ± 17.15ml vs. 17.25 ± 15.22ml; p = 0.001) and in procedure times (519.96 ± 289.45s vs. 649.61 ± 321.05s; p = 0.003) were found for MWA and RFA, respectively. Multivariate analysis identified baseline volume (p < 0.001) and composition (p < 0.033) as significant and independent predictors of VRR. Both techniques showed comparable safety. In the matched cohorts, VRRs after 6-months were similar, while a higher VRR after 12-months was observed for MWA compared to RFA (64.70 ± 13.89% vs. 58.71 ± 16.81%; p = 0.028). RFA and MWA are both safe and effective for treating BTNs. In the overall population, VRRs were similar between RFA and MWA, with MWA requiring shorter procedure times. After matching for key predictors of therapeutic response, MWA demonstrated superior efficacy at 12-months.