2017 Thyroid Radiofrequency Ablation Guideline: Korean Society of Thyroid Radiology

Comparison of US-guided thermal ablation and surgery for papillary thyroid cancer: a systematic review and meta-analysis

OBJECTIVE

We conducted the systematic review and meta-analysis to comprehensively compare ablation and surgery in terms of effectiveness, safety and multiple factors affecting life quality of patients with papillary thyroid cancer (PTC).

METHODS

PubMed, Embase, Scopus, Web of Science and EBSCO were searched for relevant studies published between January 1980 and September 2023. Two reviewers independently extracted data according to the PRISMA recommendations and assessed the quality of each study with the Cochrane Risk of Bias Tool. Pooled analyses were performed using random or fixed-effects models, as appropriate.

RESULTS

A total of 4829 patients with PTC from 19 eligible studies were included. Through the meta-analysis, similar tumor progression (OR: 1.07; 95% CI 0.78, 1.48; p = 0.66) and recurrence-free survival (OR: 0.86; 95% CI, 0.55, 1.34; p = 0.50) were found between the patients undergoing ablation and those undergoing surgery. More strikingly, the lower risk of major complications (OR: 0.31; 95% CI 0.24, 0.41; p < 0.001), the shorter hospital stay (MD = 3.67 d; 95% CI, -4.89, -2.44; p < 0.001), the abbreviated procedure time (MD: -66.33 min, 95% CI, -77.08, -55.59; p < 0.001), the less intraoperative blood loss (MD: -27.43 ml, 95% CI, -34.60, -20.27; p < 0.001) and the lower treatment cost (MD: -860.42 USD, 95% CI, -1008.03, -712.81; p < 0.001) were noticed in ablation techniques compared to surgical operation. Thermal ablation has shown multiple advantages by virtue of its percutaneous puncture compared with surgical resection.

CONCLUSION

As an effective, safe, minimally invasive and economical modality, thermal ablation might be a promising alternative to existing PTC management options.

Cytomorphological changes in thyroid nodules induced by radiofrequency ablation therapy: Emphasis on recurrent papillary thyroid carcinoma

Radiofrequency ablation (RFA) therapy is a minimally invasive treatment option for benign thyroid nodules and metastatic papillary thyroid carcinoma (PTC). This study investigated the cytomorphological changes induced by RFA in thyroid nodules. The study included patients who received RFA for benign thyroid nodules (n = 6) or recurrent PTC (n = 14), in the thyroid bed or lymph nodes following thyroidectomy. Patients underwent fine-needle aspiration (FNA) or core needle biopsy (CNB) to evaluate therapeutic responses. Most benign thyroid nodules showed acellular or hypocellular cellularity and coagulative necrosis. Thermal artifacts, fibrosis, and foreign body reactions were also noted. All cases were successfully treated, showing reduced nodule size with no recurrence during follow-up. In patients with recurrent PTC, post-RFA biopsies diagnosed 12 out of 14 samples as PTC, with most displaying degenerated tumor cells. Cytomorphological changes included acellular necrosis, nuclear pyknosis, or karyorrhexis. The second biopsy group showed lower cellularity, fewer degenerated cells, and fewer viable PTC cells than the first biopsy group. Two patients with persistent viable PTC cells after repeated RFA underwent surgical treatment. FNA and CNB effectively evaluate the response to RFA and detect residual tumors. Acellular specimens, total necrosis, and severely degenerated tumor cells indicate successful RFA, while viable cells with preserved PTC features suggest incomplete treatment.

Comparison of Microwave Ablation and Lobectomy in the Treatment of Benign Thyroid Nodules

PURPOSE

The purpose of this study is to evaluate the efficacy, safety, and advantages of microwave ablation (MWA) compared to lobectomy in the treatment of benign thyroid nodules.

METHODS

A total of 105 patients were included in the study, 49 in the MWA group and 56 in the surgical group. The mean age of the patients in the MWA group was 49.5 (±12.8) and 40.2 (±10.1) in the surgical group (p < 0.001). 81.6% of the patients in the MWA group were female and 18.4% were male. 83.9% of the patients in the surgical group were male and 16.1% were female (p = 0.75). Patients were followed for at least 12 months. The study was completed by comparing the two groups in terms of surgery-procedure times, complications, nodule sizes, thyroid function tests, symptoms, volume reduction rates (VRR), and cosmetic improvement scores.

RESULTS

The mean maximum nodule diameter in the patient group who underwent MWA was 3.5 (±1) cm at the beginning and 2.3 (±0.9) cm at the end of the 12th month (p < 0.001). VRR was 73.4% (±14.8) at the end of the 12th month (p < 0.001). Cosmetic score was 2.5 (±1) at the first month, 1.7 (±1.1) at the third month, 1 (±1) at the sixth month, and 0.6 (±0.7) at the 12th month (p < 0.001). The procedure time was 15.4 (±4.4) minutes in the patients in the MWA group, while it was 70.7 (±17.2) minutes in the surgical group (p < 0.001). No complications developed in 48 patients (98%) in the MWA group and 38 patients (67.9%) in the surgical group (p = 0.005). Voice change occurred in three patients (5.4%) in the surgical group, hematoma in two (3.6%) patients and voice change in one (1.8%) patient in the MWA group. Hypothyroidism developed in eight patients in the surgical group, while hypothyroidism did not develop in the MWA group (p = 0.007).

CONCLUSION

MWA is a safe and effective treatment method for benign thyroid nodules. It has many advantages over thyroidectomy, such as fewer complications, shorter procedure time, no need for hospitalization and general anesthesia, and good cosmetic results.

CLINICAL SIGNIFICANCE

Compared with surgery, MWA is a safe, effective, and cost-effective treatment for benign thyroid nodules.

Thyroid Dysfunction Following Thermal Ablation of Large Solid and Solid-Predominant Thyroid Nodules

OBJECTIVES

Thermal ablation (TA) is an alternative to lobectomy for thyroid nodules (TNs). While it is believed that thyroid function remains stable after TA for cystic TNs, the impact of TA on solid TNs, especially the large ones, is less explored. This study investigates changes in thyroid hormones after TA in patients with solid-predominant TNs and identifies potential risk factors for thyroid dysfunction after TA.

METHODS

Euthyroid patients with solid-predominant TNs (≥ 80% solid) were enrolled. The volume, diameter, and cytopathology of TNs were assessed before TA. TA was performed using either microwave or radiofrequency ablation. Thyroid hormone levels were measured at 1 week and 1, 3, 6, and 12 months after TA.

RESULTS

Seventy-seven euthyroid patients with TNs were included. The euthyroid rate dropped to 70.1% at 1 week after TA but improved to over 90% by 1 month and returned to 100% by 12 months. At 1 week after TA, subclinical hyperthyroidism and hyperthyroidism were observed, with elevated thyroxine, free triiodothyronine, free thyroxine, and thyroglobulin antibody levels, along with decreased thyroid-stimulating hormone (TSH) levels. The diameter and total volume of TNs were positively correlated with thyroid dysfunction, while TSH-baseline was negatively correlated with thyroid dysfunction 1 week after TA. A larger diameter and lower baseline TSH were identified as independent risk factors for thyroid dysfunction.

CONCLUSIONS

TA may cause short-term thyroid dysfunction, especially in patients with large TNs. Monitoring of thyroid hormone levels is recommended from 1 week to 3 months after TA to manage potential thyroid dysfunction effectively.

The association between volume reduction ratio and time after ultrasound-guided microwave ablation for benign thyroid nodules of different compositions

Background

Ultrasound-guided microwave ablation (MWA) is effective in the treatment of benign thyroid nodules (BTNs); however, there are large individual differences in the degree of lesion absorption and shrinkage speed. Although the internal components of nodules are important influential factors, few studies have reported temporal changes in the volume reduction ratio (VRR) in BTNs with different compositions. Therefore, this study aimed to explore how the thyroid nodule VRR changes over time and determine when it increases most significantly for BTNs of different compositions after MWA.

Methods

This is a retrospective study. We consecutively collected patients that received MWA for BTNs from July 2020 to June 2021, with 12 months of follow-up, and VRR >50% as effective treatment indicator. A generalized additive model was used to analyze temporal changes in the VRR in BTNs of different compositions, and a log-likelihood ratio test of the segmented regression model was used to determine a potential threshold. We evaluated the consistency of two operators in MWA of BTNs.

Results

In total, 221 treatment-effective nodules (216 patients) were included, in which 21 were predominantly cystic, 61 were predominantly solid, and 139 were solid nodules. A non-linear relationship was detected between VRR and time. In predominantly cystic nodules, the VRR increased by 36% per month until 2.0 months and by 1.4% per month after 2.0 months. In predominantly solid nodules, the VRR increased by 30.6% per month until 2.3 months and by 0.7% per month after 2.3 months. In solid nodules, the VRR increased by 17.4% per month until 4.3 months and by 0.3% per month after 4.3 months. Intraclass correlation coefficient (ICC) was 0.839 (95% confidence interval: 0.773, 0.887), indicating good consistency between the two operators.

Conclusions

The VRR after ultrasound-guided MWA for different components of BTNs was non-linearly related with follow-up time, and there was a threshold effect.

Predicting the efficacy of microwave ablation of benign thyroid nodules from ultrasound images using deep convolutional neural networks

BACKGROUND

Thyroid nodules are frequent in clinical settings, and their diagnosis in adults is growing, with some persons experiencing symptoms. Ultrasound-guided thermal ablation can shrink nodules and alleviate discomfort. Because the degree and rate of lesion absorption vary greatly between individuals, there is no reliable model for predicting the therapeutic efficacy of thermal ablation.

METHODS

Five convolutional neural network models including VGG19, Resnet 50, EfficientNetB1, EfficientNetB0, and InceptionV3, pre-trained with ImageNet, were compared for predicting the efficacy of ultrasound-guided microwave ablation (MWA) for benign thyroid nodules using ultrasound data. The patients were randomly assigned to one of two data sets: training (70%) or validation (30%). Accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve (AUC) were all used to assess predictive performance.

RESULTS

In the validation set, fine-tuned EfficientNetB1 performed best, with an AUC of 0.85 and an ACC of 0.79.

CONCLUSIONS

The study found that our deep learning model accurately predicts nodules with VRR < 50% after a single MWA session. Indeed, when thermal therapies compete with surgery, anticipating which nodules will be poor responders provides useful information that may assist physicians and patients determine whether thermal ablation or surgery is the preferable option. This was a preliminary study of deep learning, with a gap in actual clinical applications. As a result, more in-depth study should be undertaken to develop deep-learning models that can better help clinics. Prospective studies are expected to generate high-quality evidence and improve clinical performance in subsequent research.

Thyrotoxicosis due to Hashimoto's disease triggered by radiofrequency ablation for low-risk papillary thyroid microcarcinoma: A case report

This paper reports a case of acute thyrotoxicosis (Hashitoxicosis) in a 48-year-old woman following RFA for a low-risk papillary thyroid microcarcinoma. This case highlights the importance of considering preprocedural thyroid antibody testing to anticipate potential autoimmune reactions. Further studies are recommended to clarify the role of such testing in predicting adverse immune responses following thyroid RFA.

A novel computer-aided energy decision-making system improves patient treatment by microwave ablation of thyroid nodule

The current basis of microwave ablation (MWA) energy use for thyroid nodules (TN) is inadequate, leading to tissue carbonization, which is strongly associated with complications and poor prognosis. This study aims to devise a novel energy decision-making system to improve the subjective use of energy in current MWA procedures. Data from 916 subjects (1364 TN) across three medical centers were collected. In the first two sets, the single-stitch ablation needle energy (ANE) was calculated by analyzing MWA procedure videos. The causes of TN over-ablation (carbonization) were examined, and the relationship between well-ablated TN and ANE was explored based on TN attributes (volume and Young's modulus). Three-dimensional (3D) reconstruction of TN was performed, and a computer-aided model was constructed to optimize the distribution of the ANE field within the 3D-TN. Subsequently, a novel energy decision-making system was developed and tested. The third set was used for external validation. The cause of TN carbonization was found to be related to the overload of ANE with corrected Young's modulus and the selection of mismatched ablation needle power (ANP). A precise ANE model (Model 1) based on well-ablated TN and a needle-placement model (Model 2) based on the 3D-TN and ANP were subsequently constructed. The coupled new energy decision-making system (Model 1 + 2) demonstrated strong clinical generalization capabilities. In conclusion, this novel energy decision-making system can effectively improve the use of MWA energy, significantly promoting the precise treatment of TN.

A preliminary study of microwave ablation for Bethesda IV follicular neoplasms (≤3 cm)

OBJECTIVES

To evaluate the feasibility, safety, and efficacy of microwave ablation (MWA) for the treatment of patients with Bethesda IV follicular neoplasms (FNs) (≤3 cm).

METHODS

In the retrospective study, patients who underwent MWA for Bethesda IV FNs (≤3 cm) were included. Technical success, volume reduction, disease progression, and adverse event (AE) rates were analysed postablation.

RESULTS

The study cohort consisted of 44 patients with a mean age of 48.2 ± 15.7 years. The median follow-up period was 16 months (interquartile range [IQR]: 9-24 months). The technical success rate was 100%. The median volume reduction ratio (VRR) reached 100% (IQR: 98.8%-100.0%) after the 18th month of follow-up. The disease progression rate was 4.5% (2/44), and both of those patients experienced local recurrence. The overall AE rate was 9.1% (4/44), and AEs included 3 cases of voice hoarseness and 1 case of cough.

CONCLUSION

This study presents promising clinical outcomes regarding the feasibility, efficacy, and safety of MWA for the treatment of patients with Bethesda IV FNs ≤ 3 cm.

ADVANCES IN KNOWLEDGE

The study highlights the high technical success rate, low disease progression rate and AE rate of MWA for FNs, which underscores its potential for broader application. Future research should aim to validate these results in larger populations to increase the scope of therapy for FNs.

Complications of ultrasound-guided thermal ablation of thyroid nodules and associated risk factors: an experience from 9667 cases

OBJECTIVES

To evaluate the safety of ultrasound-guided thermal ablation (UGTA) for thyroid nodules (TNs) by analysing complications and related risks.

MATERIALS AND METHODS

This retrospective, single-centre study reviewed patients who underwent UGTA (microwave or radiofrequency ablation) between January 2018 and March 2023. The incidence of complications was recorded and assessed during and immediately after ablation,1-3 h later, and at 1 month, 3 months, and 6 months. Univariate and multivariate analyses were performed to identify risk factors for hoarseness and haemorrhagic complications.

RESULTS

We reviewed 9667 cases in this study. Overall, 4494 (46.49%) cases underwent microwave ablation, while 5173 (53.51%) cases underwent radiofrequency ablation. The overall complication rate was 4.43%. The incidence of major complications was 1.94% (haemorrhage, 1.32%; hoarseness, 0.54%; and symptomatic aseptic necrosis, 0.08%). The incidence of minor complications was 2.45%. A large nodule volume, radiofrequency ablation, hyper-enhancing nodules, benign nodules, higher preoperative blood pressure, hyperthyroidism, and higher ablation power were independent risk factors for haemorrhage. Dorsal nodules and a higher ablation power were independent risk factors for hoarseness. All complications were resolved.

CONCLUSION

This study suggests that UGTA is a safe treatment for TNs. Several risk factors for haemorrhage and hoarseness should be considered before performing UGTA. Different ablation modalities should be considered for patients with different conditions.

CLINICAL RELEVANCE STATEMENT

Thermal ablation may be a safe treatment for eligible patients with TNs.

KEY POINTS

We analysed the complications and risk factors associated with UGTA in 9667 cases. The complication rate was 4.43%; 1.94% were major complications. Risk factors of haemorrhage and hoarseness should be considered. UGTA was a safe method for the treatment of TNs.

Thermal Ablation for Low-risk Papillary Thyroid Carcinoma: Comparing Outcomes in T1N0M0 and T2N0M0 PTC

BACKGROUND

Thermal ablation (TA) has demonstrated promising treatment efficacy and safety in T1N0M0 papillary thyroid carcinoma (PTC). However, the efficacy and safety of TA for T2N0M0 PTC still lack sufficient evidence.

PURPOSE

To compare the technical effectiveness, disease progression, and complications of TA in the treatment of solitary T1N0M0 versus solitary T2N0M0 PTC.

MATERIALS AND METHODS

In this retrospective study, 1159 patients with PTC treated with TA from January 2015 to June 2024 were included and divided into two groups according to tumor stage. Propensity score matching (PSM) was used to control for confounding factors. Kaplan-Meier curves were used to analyze the disease progression.

RESULTS

After PSM (1:4), 41 patients (median age 35 years [IQR 30-49]; 30 women) were included in the T2 group, and 164 patients (median age 34 years [IQR 29-43]; 108 women) were included in the T1 group. The median follow-up durations were 26 months (IQR 13-49) for the T2 group and 25 months (IQR 12.3-43) for the T1 group. The technical success rates were 100% in the two groups. Statistical analysis showed no significant differences in disease progression between the T1 and T2 groups (0.6% vs. 4.9%, P=0.103), nor in disease progression-free survival rates (98.2% vs. 88.6%, log-rank P=0.052). The incidence of major complications was higher in the T2 group than that in the T1 group (1.8% vs. 17.1%, P=0.001). No permanent hoarseness was observed in the two groups.

CONCLUSION

TA could be a safe and effective option in the treatment of solitary T2N0M0 PTC. No significant difference was observed in disease progression between T1N0M0 and T2N0M0 PTC.

Ultrasound-Guided Thermal Ablation vs Surgery in T1N0M0 Papillary Thyroid Carcinoma: A Systematic Review and Meta-analysis

RATIONALE AND OBJECTIVES

Ultrasound-guided thermal ablation (TA) offers a minimally invasive alternative to surgery for T1N0M0 papillary thyroid carcinoma (PTC), but its efficacy and safety remain controversial. This meta-analysis aimed to evaluate and compare the outcomes of TA and surgery in treating T1N0M0 PTC, encompassing both T1a and T1b stages.

MATERIALS AND METHODS

We conducted a systematic review and meta-analysis including studies comparing TA and surgery for T1N0M0 PTC up to October 23, 2024. Standardized mean differences and odds ratios (OR) with 95% confidence intervals (CI) were calculated for primary and secondary outcomes.

RESULTS

Sixteen studies with a total of 5045 patients were analyzed. No significant differences were observed in recurrence (OR=1.464; 95% CI=0.881, 2.433; P=.141), lymph node metastasis (OR=0.817; 95% CI=0.492, 1.356; P=.434), transient hoarseness (OR=0.700; 95% CI=0.339, 1.445; P=.334), hematoma (OR=0.528; 95% CI=0.187, 1.492; P=.228), and infection (OR=0.368; 95% CI=0.060, 2.268; P=.281). Notably, TA significantly reduced permanent hoarseness, hypoparathyroidism, dysphagia, procedure time, hospitalization, cost, estimated blood loss, and surgical incision (all P<.05). The subgroup analyses demonstrated similar primary outcomes within each subgroup, including tumor stage (T1a/T1b), type of TA (microwave/radiofrequency), and follow-up time (short-term/long-term).

CONCLUSION

Ultrasound-guided TA is a safe and effective alternative to surgery for both T1a and T1b stages of T1N0M0 PTC, offering comparable prognostic outcomes with fewer complications, lower costs, and faster recovery.

Microwave ablation for benign thyroid nodules with cosmetic problems and related factors for post-ablative complete relief: a two-center retrospective study

PURPOSE

To investigate the efficacy of ultrasound (US)-guided percutaneous MWA for benign thyroid nodules with cosmetic problems and identify related factors contributing to post-ablative complete relief (CR).

METHODS

This retrospective study reviewed the efficacy of MWA in treating thyroid nodules in patients with cosmetic problems who underwent MWA from January 2021 to May 2023. Patients were followed up at 1, 3, and 6 months after MWA. Pre-treatment clinical characteristics, conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS) features were analyzed to explore their correlation with cosmetic improvement, defined as a cosmetic score of 1 or 2 at the 6-month follow-up. Univariable and multivariable regression analyses were carried out to identify variables associated with CR, and the related nomogram was established. Calibration curve and decision curve analysis were used to evaluate the nomogram performance.

RESULTS

118 patients with 118 nodules were included in the study. During the 1-, 3- and 6-month follow-up, the mean volume reduction ratios (VRR) were 2%, 36% and 73%, respectively. 22.0% (26/118), 57.6% (68/118), and 89.8% (106/118) patients achieved CR of cosmetic problems at 1, 3, and 6 months after MWA. In multivariable analysis, three variables (i.e., non-hashimoto's thyroiditis [HT] [OR: 90.036, P = 0.001], nodule location not close to danger triangle area [OR: 66.812, P = 0.003], early hyperenhancement on CEUS [OR: 0.035, P = 0.024]) were found to be closely associated with CR of cosmetic problems at 6 months after MWA. A nomogram model was constructed, and its accuracy was well validated (i.e., C-index = 0.914).

CONCLUSION

MWA was effective and safe for treating benign thyroid nodules with cosmetic problems. Non-HT, nodule location not close to danger triangle area, and early hyperenhancement on CEUS were associated with CR of cosmetic problems after MWA.

Preliminary Report Examining Efficacy and Safety of Radiofrequency Ablation for the Treatment of Skin-Involving Recurrent Thyroid Cancer

Background: This study assessed the efficacy and safety of ultrasound (US)-guided radiofrequency ablation (RFA) for treatment of skin-involving recurrent thyroid cancer. Methods: In this retrospective case series study, 43 patients (mean age: 67.9 ± 14.4 years; 31 females) with skin-involving recurrent thyroid cancer were treated with RFA for a total of 50 tumors between May 2008 and March 2023. The location of the tumor was classified into epidermis, dermis, or hypodermis on the basis of the involved skin layer. After RFA, the technique efficacy (absence of detectable vasculature and volume reduction at 12 months), clinical success (resolution of symptoms or cosmetic problems), volume reduction ratio (VRR), complete disappearance of tumor, and complications were assessed. Results: Of the 50 recurrent tumors, 9 involved the epidermis, 10 involved the dermis, and 31 involved the hypodermis. A total of 88 RFA sessions (mean, 1.8; range: 1-6) were performed. The technique efficacy at 1 year was 72% (36/50 [confidence interval or CI: 59.6-84.4%]). At the last follow-up (median [interquartile range]: 2.7 [1.1-4.5] years), the clinical success rate was 86% (44/50), the complete disappearance rate 54% (27/50), and the mean VRR 77.3% ± 44.2%. In a subgroup analysis comparing epidermis/dermis vs. hypodermis, there was no statistical difference in technique efficacy (57.9% [11/19] vs. 80.6% [25/31], p = 0.085), clinical success rate (78.9% [15/19] vs. 90.3% [28/31], p = 0.265), complete disappearance rate (42.1% [8/19] vs. 51.6% [16/31], p = 0.541), or mean VRR (65.5% vs. 84.6%, p = 0.141). Skin burns were observed in 4.9% per treatment session (2/41 [CI: 0-11.3%]) of epidermis/dermis-involving tumor procedures and none of the hypodermal tumor procedures. No patients experienced life-threatening or major complications. Conclusions: RFA might serve as a promising approach for managing skin-involving recurrent thyroid cancer, with no major complications reported in this preliminary study. Recurrent tumors involving the epidermis/dermis may pose a higher risk of skin burns than tumors involving the hypodermis. Early intervention with RFA before the tumor extends to the epidermis/dermis may thus be preferable.

Radiofrequency Ablation for Solitary Autonomously Functioning Thyroid Nodules: Multicenter Study from Latin America

Background: Autonomously functioning thyroid nodules (AFTNs) represent ∼5% of all thyroid nodules and often necessitate definitive treatments such as surgery or radioiodine (131I), both of which have inherent risks. Radiofrequency ablation (RFA) has emerged as an effective and safe therapeutic option for managing AFTNs. This study aims to assess the effectiveness and safety of RFA for solitary AFTNs in various countries across Latin America. Methods: This retrospective, observational, multicenter cohort study included patients with a solitary AFTN that was histologically confirmed as benign and treated with a single session of RFA. The study included an analysis of patient demographics, sonographic characteristics of the nodules, thyroid profile assessment at each follow-up visit, evaluation of clinical symptoms to determine the achievement of a euthyroid state, and the measurement of nodule volume reduction. In addition, a bivariate analysis was conducted to identify associations between these variables and the resolution of hyperthyroidism. Results: Our study enrolled 81 patients with a solitary, benign AFTN. The volume reduction ratio (VRR) consistently increased over the follow-up period, with medians of -50%, -74.9%, -78.4%, and -90.2% at 1, 3, 6, and 12 months, respectively. The rate of resolution of hyperthyroidism was 93.8% (76/81). Following the RFA procedure, 58.02% of patients (47/81) normalized their thyrotropin levels within 1 month of follow-up, and by 3 months, an additional 33.3% had achieved normalization (27/81). Notably, a baseline volume ≥10, 20, or 30 mL did not affect the achievement of clinical success. In bivariate analyses, a VRR ≥50% at the 6-month follow-up was associated with the resolution of hyperthyroidism. Overall complications occurred in 6.2% of patients (5/81), including 1.2% (1/81) of a major complication (transient Horner syndrome), 3.7% cases of transient dysphonia (3/81), and 1.2% (1/81) of hypothyroidism requiring low-dose levothyroxine replacement. Conclusions: The results of this multicenter study suggest that RFA is a promising treatment option for patients with solitary AFTN, regardless of their baseline characteristics, including volume, age, or composition. The clinical success of the intervention may be related to the VRR at 6 months.

Ultrasound-guided thermal ablation therapy for papillary thyroid carcinoma: a bibliometric analysis from 2000 to 2023

Background

Papillary thyroid cancer (PTC) is increasingly treated with procedures. However, there is a lack of relevant systematic evaluation articles. Therefore, this study aims to explore the research landscape of PTC thermal ablation through bibliometric analysis.

Methods

We searched publications related to PTC thermal ablation therapy from January 1, 2000 to December 31, 2023, from the Web of Science Core Collection (WoSCC). Subsequently, bibliometric analyses were then performed using the R package "bibliometrix", as well as VOSviewer and CiteSpace software, to visualize data on countries, institutions, journals, authors, keywords, and references.

Results

A total of 283 publications from 17 countries were retrieved, and the number of publications had shown a steady increase over the past decade, with China, the USA and South Korea being the top three contributing countries. The Chinese People's Liberation Army General Hospital was the most prolific institution, with the International Journal of Hyperthermia being the most frequent publisher. The author with the highest number of publications was Yukun Luo. "Radiofrequency ablation" was identified as the most commonly used keyword, indicating a potential research hotspot for the future.

Conclusions

This bibliometric study comprehensively analyzed publications on PTC thermal ablation, providing valuable insights into the history and current status of this research field, while also offering guidance for future research directions.

Changes in thyroid function after thermal ablation of thyroid nodules

Purpose

To evaluate changes in thyroid function post-thermal ablation (TA) of thyroid nodules and to identify risk factors associated with post-ablation thyroid function abnormalities.

Materials and methods

A retrospective analysis of 2,264 cases treated with TA between June 2015 and July 2024 was conducted, including 1,169 benign thyroid nodules (BTNs) and 1,095 papillary thyroid carcinoma (PTC) cases. Thyrotropin (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels were measured before treatment and at 1, 3, 6, 9, and 12 months post-ablation.

Result

FT3 levels remained significantly reduced at 12 months post-ablation (3.04 ± 0.42 vs. 3.15 ± 0.36 pg/mL; p < 0.001). In contrast, FT4 levels showed a persistent increase at 12 months (1.36 ± 0.69 vs. 1.27 ± 0.15 ng/dL; p < 0.001). Although TSH levels decreased slightly over time, they remained elevated at 12 months compared to baseline (1.80 ± 1.17 vs. 1.73 ± 0.84 μIU/mL; p = 0.029). At the end of the follow-up period, the incidence of thyroid function abnormalities was 5.07% (18/355), with only one patient requiring Thiamazole for antithyroid therapy. The cumulative incidence of thyroid function abnormalities was notably higher in the PTC group compared to the BTN group (17.80% vs. 10.94%; p < 0.001). Pre-ablation TSH levels (OR= 2.06; 95% CI, 1.77-2.39; p < 0.001), Hashimoto's thyroiditis (OR = 2.66; 95% CI, 1.88-3.77; p < 0.001), and multiple nodules were positively correlated with the occurrence of thyroid function abnormalities. The cutoff value of TSH was 2.015 μIU/mL with a sensitivity of 0.527 and a specificity of 0.246 (AUC = 0.625).

Conclusion

Thermal ablation had a minimal impact on thyroid function. Pre-ablation TSH levels, Hashimoto's thyroiditis, and multiple nodules were risk factors for post-ablation thyroid function abnormalities.

A clinical study on microwave ablation of T1N0M0 papillary thyroid carcinoma locating in dangerous region

To evaluate the feasibility, safety and efficiency of the microwave ablation (MWA) of T1N0M0 papillary thyroid carcinoma (PTC) locating in dangerous region. This is a clinical retrospective study, and the data of patients who underwent thermal ablation for T1N0M0 PTC from June 2016 to March 2021 were reviewed. After ablation, the rates of technical success, as well as the changes in tumor size and volume, tumor disappearance, disease progression, and complications, were assessed. According to the tumor size, the patients were divided into T1a and T1b subgroups. There was a total of 94 cases enrolled in the present study. The mean age was 43.06 ± 11.51 years (22-65 years). The median follow-up time was 33 months (25-75% IQR 24-44; 12-85months). The technical success rate was 100%. Due to expanding ablation, the MD and volume of the ablation zone increased at the 1st and 3rd months and decreased from the 12th month after ablation (p < 0.05 for all). At the end of follow-up, the complete disappearance of ablation zone occurred in 78(78/94, 82.98%) cases, including 65 (65/75, 86.67%) cases in T1a subgroup and 13(13/19, 68.4%) cases in the T1b subgroup. There was no difference between the two subgroups (p = 0.121). 5 (5/94,5.3%) patients developed disease progression, and all of them were in T1a subgroup (5/75, 6.67%). There was not significantly different between two subgroups (p = 0.559). The complication rate was 15.96% (15/94). Recurrent laryngeal nerve (RLN) injury encountered in 11 (11/75, 14.7%) cases in the T1a subgroup and 4 (4/19, 21.1%) cases in the T1b subgroup. No significant difference between the two subgroups (p = 0.74). This preliminary study indicates that MWA is an effective treatment for T1N0M0 PTC locating in dangerous region.

Radiofrequency Ablation of Benign Thyroid Nodules: 10-Year Follow-Up Results From a Single Center

OBJECTIVE

The long-term efficacy of radiofrequency ablation (RFA) for the treatment of benign thyroid nodules remains unclear. We aimed to evaluate the long-term efficacy, emphasizing single-session RFA, and identify the factors associated with cases requiring additional RFA sessions to achieve a comparable volume reduction rates (VRR).

MATERIALS AND METHODS

We retrospectively evaluated benign thyroid nodules treated with RFA between 2008 and 2018. Treatment efficacy at the 5- and 10-year follow-ups was analyzed. Additionally, subgroup analysis comparing technique efficacy, such as the final VRR, between the single- and multi-session RFA groups was performed. Continuous variables were analyzed using the two-sample t-test or Mann-Whitney U test, and categorical variables were analyzed using the Chi-square or Fisher's exact test.

RESULTS

A total of 267 nodules from 237 patients (age: 46.3 ± 15.0 years; female: 210/237 [88.6%]) were included. Of these, 60 were analyzed for the 5-year follow-up (mean follow-up duration ± standard deviation: 5.8 ± 0.4 years) and 29 for the 10-year follow-up (10.9 ± 0.9 years). Single-session RFA showed a median VRR of 95.7% (5th year) and 98.8% (10th year), while multi-session RFA showed comparable median VRRs of 97.4% (5th year) and 96.9% (10th year). The vascularity type, demographic factors, nodular components, and locations did not significantly differ between the single-session and multi-session RFA groups. However, nodules with pre-RFA volume <10 mL were more prevalent in the single-session RFA group than in the multi-session RFA group (5th year: 64.3% [18/28] vs. 34.4% [11/32], P = 0.040; 10th year: 75.0% [12/16] vs. 23.1% [3/13], P = 0.016).

CONCLUSION

Single-session RFA may be sufficient for achieving adequate volume reduction during long-term follow-up for small-volume benign thyroid nodules. A high VRR was maintained regardless of the nodular component, location, demographic factors, or vascularity type. However, large-volume nodules may require multiple RFA sessions to achieve a comparable VRR.

Comparative efficacy and safety of radiofrequency ablation and microwave ablation in benign thyroid nodule treatment: a systematic review and meta-analysis

OBJECTIVE

Ultrasound-guided thermal ablation, including radiofrequency ablation (RFA) and microwave ablation (MWA), has become one of the main options for treating benign thyroid nodules (BTNs). To assess the efficacy of thermal ablation of BTNs, we performed a systematic review and meta-analysis of relevant studies.

MATERIALS AND METHODS

A comprehensive search of MEDLINE, EMBASE, and COCHRANE databases was performed up to September 25, 2023, to identify studies directly comparing RFA and MWA for pathologically proven BTNs and reporting clinical outcomes and complications. Data extraction and quality assessment were independently performed by two radiologists according to PRISMA guidelines. The analysis yielded the serial volume reduction ratios (VRRs) of ablated nodules for up to 12 months, symptom and cosmetic scores, and complications.

RESULTS

This analysis included nine studies with 1305 BTNs treated by RFA and 1276 by MWA. VRRs at 1 month, 3 months, and 6 months were similar between RFA and MWA, but RFA showed a significantly higher VRR (83.3%) than MWA (76.9%) at 12 months (p = 0.02). Complication rates showed no significant difference between the two methods. Symptom and cosmetic scores significantly decreased after ablation, without a significant difference between the methods. Subgroup analysis indicated a significantly higher VRR at 12 months for RFA than for MWA for less experienced investigators (≤ 10 years), but no significant difference for more experienced investigators (> 10 years).

CONCLUSION

RFA and MWA are both effective and safe methods for treating BTNs. RFA showed a higher VRR at 12 months and seems more suitable for less experienced investigators.

CLINICAL RELEVANCE STATEMENT

RFA and MWA are both effective and safe treatments for BTNs, with RFA showing a higher VRR at 12 months. Both methods offer minimally invasive and reliable treatment for thyroid nodules.

KEY POINTS

The most effective thermal ablation technique for BTNs remains undetermined. RFA showed a higher VRR at 12 months than MWA. Both techniques are effective for treating thyroid nodules; RFA offers greater benefits, particularly for less experienced investigators.

Thermal Ablation of Thyroid Nodules, From the AJR "How We Do It" Special Series

Ablation has been shown to be an effective option for treatment of well-selected patients with thyroid nodules, particularly benign nodules, and thermal ablation is being increasingly used for this purpose. The general approach to thermal ablation of the thyroid will be familiar to interventional radiologists who perform ablation in other tissues; however, thermal ablation of the thyroid has additional unique considerations. In this review, we provide evidence-based and real-world guidance on the performance of thermal ablation for the treatment of patients with thyroid nodules, drawing on our collective experience and clinical practice. We describe patient selection, ablation modalities, equipment, general procedural approach, additional technical considerations, and postprocedural follow-up. We discuss various clinical scenarios; give tips on performing specific portions of the procedure; and highlight a range of relevant anatomic, biochemical, and clinical factors as a guide for interventional radiologists in establishing a successful thyroid ablation practice.

Analysis and prediction of ablation zone absorption in papillary thyroid microcarcinoma undergoing microwave ablation

PURPOSE

This study aims to investigate the factors that influence the absorption of the ablation zone in patients with papillary thyroid microcarcinoma (PTMC) following microwave ablation (MWA) and construct a nomogram for predicting the absorption of the ablation zone.

METHODS

Data from 150 patients with 187 PTMCs who received MWA between April 2020 and April 2023 were analyzed. PTMCs were randomly divided into training and validation sets in a 7:3 ratio. Univariable and multivariable analyses of Cox regression were utilized to identify the independent variables associated with the absorption of the ablation zone in PTMC post-MWA, and a nomogram was established. The discrimination and calibration performance of the nomogram was assessed using the time-dependent receiver operating characteristic curves and calibration curves.

RESULTS

At 12 months post-MWA, a 53% proportion of complete disappearance of the ablation zone was observed. Energy delivered per milliliter of volume measured in contrast-enhanced ultrasound (CEUS) mode immediately post-MWA (Edv) and the CEUS margin at 1-month post-WMA were identified as independently correlated with the ablation zone absorption post-MWA (P = 0.001, P < 0.001 respectively). A nomogram incorporating these two factors was constructed. The areas under the receiver operating characteristic curve were all above 0.78 in the training and validation sets.

CONCLUSION

Edv and the CEUS margin at 1-month post-MWA were found to be significantly associated with complete absorption of the ablation zone in PTMC patients following MWA. The established nomogram can assist practitioners in formulating more appropriate ablation strategies and provide a clinical basis for explaining the recovery status to patients.

Effectiveness of microvascular flow imaging for radiofrequency ablation in recurrent thyroid cancer: comparison with power Doppler imaging

OBJECTIVES

To compare microvascular flow imaging (MVFI) and power Doppler ultrasonography imaging (PDUS) for detecting intratumoral vascularity in recurrent thyroid cancer both before and after radiofrequency ablation (RFA).

METHODS

This retrospective study included 80 patients (age, 57 ± 12 years; 54 women) with 110 recurrent tumors who underwent RFA between January 2021 and June 2023. A total of 151 PDUS and MVFI image sets were analyzed (85 pre-RFA, 66 post-RFA). Two readers assessed vascularity on the images using a four-point scale with a 2-week interval between PDUS and MVFI to estimate inter-reader agreement. Intra-reader agreement was determined by reinterpreting images in reverse order (MVFI-PDUS) after a 1-month gap. Additionally, diagnostic performance for identifying viable tumors after RFA was assessed in 44 lesions using thyroid-protocol CT as a reference standard.

RESULTS

MVFI demonstrated higher vascular grades than PDUS, both before (reader 1: 3.04 ± 1.15 vs. 1.93 ± 1.07, p < 0.001; reader 2: 3.20 ± 0.96 vs. 2.12 ± 1.07, p < 0.001) and after RFA (reader 1: 2.44 ± 1.28 vs. 1.67 ± 1.06, p < 0.001; reader 2: 2.62 ± 1.23 vs. 1.83 ± 0.99, p < 0.001). Inter-reader agreement was substantial (κ = 0.743) and intra-reader agreement was almost perfect (κ = 0.840). MVFI showed higher sensitivity (81.5%-88.9%) and accuracy (84.1%-86.4%) than PDUS (sensitivity: 51.9%, p < 0.01; accuracy: 63.6-70.5%, p < 0.04), without sacrificing specificity.

CONCLUSION

MVFI was superior to PDUS for assessing intratumoral vascularity and showed good inter- and intra-reader agreement, highlighting its clinical value for assessing pre-RFA vascularity and accurately identifying post-RFA viable tumors in recurrent thyroid cancer.

CLINICAL RELEVANCE STATEMENT

Microvascular flow imaging (MVFI) is superior to power-Doppler US for assessing intratumoral vascularity; therefore, MVFI can be a valuable tool for assessing vascularity before radiofrequency ablation (RFA) and for identifying viable tumors after RFA in patients with recurrent thyroid cancer.

KEY POINTS

The value of microvascular flow imaging (MVFI) for evaluating intratumoral vascularity is unexplored. MVFI demonstrated higher vascular grades than power Doppler US before and after ablation. Microvascular flow imaging showed higher sensitivity and accuracy than power Doppler US without sacrificing specificity.

Comparative efficacy, safety, and oncological outcomes of percutaneous thermal and chemical ablation modalities for recurrent metastatic cervical lymphadenopathy from thyroid cancer

BACKGROUND

Thermal and chemical ablation techniques may consolidate recurrent metastatic cervical lymph nodes as alternatives to repeat neck dissection in thyroid cancer patients. This meta-analysis aims to compare the efficacy and safety across modalities.

METHODS

Four databases were searched for studies on radiofrequency (RFA), microwave (MWA), laser (LA), and ethanol ablation (EA) treating metastatic cervical nodes from thyroid cancer. The outcomes analyzed included treatment response, oncologic control, and complications. Random effects meta-analytical pooling was conducted.

RESULTS

There were 25 studies (n = 1061 nodes) examining the four ablation methods. Patients showed comparable baseline characteristics and initial lymph node sizes ranging from 0.96 to 1.28 cm. All modalities achieved substantial node volume reduction (88.4 %) and disappearance (62.8 %), with significant biochemical decline (from 6.01 to 1.13 ng/ml, p = 0.18 between groups). MWA showed the highest volume reduction (99.4 %) and disappearance rate (87.6 %) versus slower efficacy of RFA (93.0 %, 72.1 %), LA (77.9 %, 62.5 %), and EA (81.8 %, 58.4 %). New malignancy/metastases risks ranged from 0.03 % to 1.3 % without between-group differences (p = 0.52). Major complications were absent; transient voice changes (0.05%-10.6 %) and neck pain (0.0%-5.9 %) were the main overall complaints. However, overall complication rates significantly varied by modality (1.1%-10.6 %; p = 0.003).

CONCLUSIONS

Thermal and chemical ablation is effective in controlling the metastatic disease burden in patients with thyroid cancer, offering a potentially less morbid and non-surgical alternative to re-operation. Additional prospective data could confirm the long-term equivalent of revision neck dissection and stratify patients based on concomitant Hashimoto's and genomic mutations. Clarifying optimal patient selection and standardizing prognostic indexing could further enhance utilization.

Radiofrequency Ablation of Low-Risk Papillary Thyroid Microcarcinoma: A Retrospective Cohort Study Including Patients with More than 10 Years of Follow-up

Background: The longest reported follow-up for thermal ablation of papillary thyroid microcarcinoma (PTMC) is 5 years. We evaluated the long-term efficacy and safety of radiofrequency ablation (RFA) in patients with low-risk PTMC with clinical follow-up of more than 10 years. Methods: In this retrospective cohort study, we included patients with low-risk PTMC who had more than 10 years of follow-up after ultrasound (US)-guided RFA (performed between May 2008 and December 2013). Sixty-five consecutive patients with 71 low-risk PTMCs who were unsuitable for surgery or declined surgery were included. Before RFA, all patients underwent US and thyroid computerized tomography. Repeat RFA for staged ablation was performed when the first RFA did not secure sufficient safety margins because of the tumor closely abutting the recurrent laryngeal nerve. Follow-up US imaging was performed at 1 week, 3 months, 6 months, every 6 months until 2 years, and then annually afterward. Primary outcomes were the respective cumulative rates of disease progression (defined by local tumor progression, lymph node, or distant metastasis), newly developed thyroid cancer, and conversion surgery. Secondary outcomes were serial volume reduction rate (VRR), complete disappearance rate of ablated PTMC, and adverse events associated with procedures. Results: Of 65 patients included in the study, 60 had unifocal and 5 had multifocal PTMCs. The mean number of RFA sessions per tumor was 1.2, and the median follow-up duration was 151 months (interquartile ranges, 131-157). Twenty percent (13/65) of patients required repeat RFA. There were no cases of disease progression. Five patients (5/65, 7.7%) developed a new papillary thyroid cancer (four treated with RFA and one with lobectomy). At 24 months, the mean VRR was 100%, and this was maintained throughout the final follow-up. The complete tumor disappearance rates after one or more RFA treatments were 40.8% (29/71), 74.6% (53/71), and 100% (71/71) at 6, 12, and 24 months, respectively. One major (subclinical hypothyroidism) and three minor adverse events occurred. Conclusions: In our experience, RFA of low-risk PTMC is effective and safe. During more than 10 years of follow-up, we observed no incident local tumor progression nor metastases, but 7.7% of patients developed a new papillary thyroid cancer.

Radiofrequency Ablation for Locoregional Structural Incomplete Response in Differentiated Thyroid Cancer: Initial Experience in Greece

Background/Objectives: Structural incomplete response (SIR) (persistence/recurrence) may occur in 2-6% of low-risk differentiated thyroid cancer (DTC)-cases and in 67-75% of high risk. Regarding locoregional disease, surgery is the optimal therapeutic modality if the smallest dimension of the targeted node is ≥8 mm or ≥10 mm (central or lateral compartment). In the presence of smaller nodes, contraindications or the patient's unwillingness for reoperation, active surveillance (AS) or minimally invasive treatments (MITs) may be considered. Methods: We retrospectively studied eight DTC patients with SIR confirmed by ultrasound (U/S)-guided fine-needle aspiration cytology (FNAC) and the measurement of Thyroglobulin (Tg) in the washout fluid. Fourteen malignant lesions were ablated by radiofrequency (RF). We assessed prior to RF ablation (RFA) and consecutively at one month, three months and, then, every three months the volume of each lesion, serum Tg and Anti-Tg antibodies and calculated the volume reduction ratio (VRR). Results: Patients were followed for a mean period of 13.25 months (range: 4-24) after RFA was performed. The targeted lesions reduced significantly from a median volume of 0.24 mL (range: 0.09-0.9) to 0.02 mL (range: 0-0.03) (p < 0.05), with a median VRR of 94.5% (range: 78-100%) and concomitant significant biochemical remission (decrease in serum Tg from a median of 1.05 ng/mL to 0.2 ng/mL, p < 0.05). In one patient with an aggressive radioiodine (RAI)-refractory histological variant, re-recurrence was documented, which was successfully re-ablated by RF. In two patients, Horner syndrome was diagnosed as an RFA complication, which was totally resolved within six months. Conclusions: RFA may be considered as an effective and safe MIT in selective DTC patients with SIR, especially in cases of smaller lesions. Additional prospective studies are needed, including aggressive DTC histological variants towards a tailored therapeutic approach.

Comparative outcomes of ultrasound-guided radiofrequency ablation vs. microwave ablation for patients with T1N0M0 papillary thyroid carcinoma: a retrospective cohort study

OBJECTIVE

To compare the clinical outcomes between radiofrequency ablation (RFA) and microwave ablation (MWA) for the treatment of T1N0M0 papillary thyroid carcinoma (PTC) in a large cohort.

MATERIALS AND METHODS

This retrospective study included 1111 patients with solitary T1N0M0 PTC treated with RFA (n = 894) or MWA (n = 215) by experienced physicians. A propensity score matching was used to compare disease progression, including lymph node metastases (LNM), recurrent tumors and persistent tumors, recurrence-free survival (RFS), volume reduction ratio (VRR), and complications between the RFA and MWA groups. The subgroup outcomes of T1a and T1b tumors treated with RFA and MWA were also compared.

RESULTS

During a mean follow-up period of 41.7 ± 12.6 months, the overall incidence rates of disease progression, LNM, recurrent tumors, and persistent tumors were 2.1%, 0.7%, 1.2%, and 0.2%, respectively. Eight patients (0.7%) experienced transient voice change and recovered within 3 months. After 1:1 matching, there were no significant differences in disease progression (3.3% vs. 3.7%, p = 0.793), LNM (1.4% vs. 1.9%, p = 1.000), recurrent tumor (1.4% vs. 1.9%, p = 1.000), persistent tumors (0.5% vs. 0%, p = 0.317), RFS rates (96.7% vs. 96.3%, p = 0.821), VRR (99.3 ± 3.0% vs. 98.3 ± 8.5%, p = 0.865), tumor disappearance rate (87.9% vs. 81.4%, p = 0.061) and complications (1.4% vs. 1.9%, p = 1.000) between the RFA and MWA groups. For T1a and T1b tumors, clinical outcomes were comparable between RFA and MWA.

CONCLUSIONS

RFA and MWA did not show significant differences in clinical outcomes for T1N0M0 PTC. The choice between RFA and MWA could depend on physician expertise and resources of local center resources. A qualified and experienced physician with extensive knowledge of the modalities is recommended when thermal ablation is performed.

KEY POINTS

Question With radiofrequency ablation (RFA) and microwave ablation (MWA) used worldwide for T1N0M0 papillary thyroid carcinoma (PTC), is one of them superior to the others? Findings There were no significant differences in disease progression, recurrence-free survival, volume reduction ratio, tumor disappearance, or complications between techniques for solitary T1N0M0 papillary thyroid carcinoma. Clinical relevance The choice between RFA and MWA could depend on physician expertise and resources of the local center resources. A qualified and experienced physician with extensive knowledge of the modalities is recommended when thermal ablation is performed.

Improvement in thyroid-specific quality of life following radiofrequency ablation of benign thyroid nodules: A USA study

BACKGROUND

Radiofrequency ablation is an effective minimally invasive technique for benign thyroid nodules, with European and Asian studies reporting improved quality of life following treatment. We aimed to assess the thyroid-related quality of life of patients with benign thyroid nodules treated with radiofrequency ablation in the United States.

METHODS

This is a prospective single-institution study of patients treated with radiofrequency ablation over a 4-year period. Nodule characteristics and Thyroid-Related Patient-Reported Outcome (ThyPRO)-39 scores were assessed at baseline, 3 months post-procedure, and last follow-up (range: 3-12 months). Wilcoxon signed-rank test was used to assess differences in scores before and after radiofrequency ablation with standardized effect size analysis.

RESULTS

A total of 56 patients with 76 nodules were treated. The median volume reduction ratio at 1, 3, 6, and 12 months was 44.9% (interquartile range: 27.3-57.3), 65.2% (53.5-73.1), 69.7% (63.5-81.9), and 79.6% (66.2-88.9), respectively. At 3-month follow-up, significant improvement (P < .05) was observed for goiter symptoms (28.9 vs 10.8), anxiety (30.7 vs 19.3), and appearance (29.9 vs 10.8). At last follow-up, significant improvement (P < .05) was observed for goiter symptoms (28.9 vs 8.9), anxiety (30.7 vs 22.3), appearance (29.9 vs 10.8), and overall quality of life (30.3 vs 11.1). Effect sizes were moderate for appearance (standardized effect size 0.5-0.8) at last follow-up.

CONCLUSION

In the largest US study to date assessing quality of life following radiofrequency ablation, we observed an expected volume reduction ratio and improvements in thyroid-specific quality of life, particularly in the goiter, anxiety, and appearance domains.

Thyroid Radiofrequency Ablation-Thermal Effects on Recurrent Laryngeal Nerve Using Continuous Intraoperative Neuromonitoring Animal Model

OBJECTIVE

When performing radiofrequency ablation for thyroid nodules, it is essential to avoid thermal injury to the recurrent laryngeal nerve. This porcine animal model study used continuous intraoperative neuromonitoring to investigate the thermal safety parameters of thyroid radiofrequency ablation.

STUDY DESIGN

Porcine animal study.

SETTING

University animal laboratory.

METHODS

Twelve piglets were tested at different radiofrequency power levels, and the real-time electromyography signal changes were recorded under continuous intraoperative neuromonitoring. The spread heat study (8 piglets) included spontaneous recovery tests and cold water irrigation tests to investigate the safety distance from the recurrent laryngeal nerve to the active tip during 5-second activation with standard stimulation patterns. The residual heat study (4 piglets) investigated the safety cooling durations by touching the recurrent laryngeal nerve with the tip after a 5-second activation.

RESULTS

In the spread heat study, substantial signal attenuation events were observed at an spread heat distance of 2, 3, 5, and 5 mm when the power was set as 10, 20, 30, and 50 W, respectively. No signal recovery could be observed in 20 minutes with or without cold water irrigation in the injured recurrent laryngeal nerve area. The residual heat study shows the residual thermal effect of the tip is minimal, and no substantial signal attenuation event was observed at all experiments.

CONCLUSIONS

This innovative study established the thermal safety parameters for radiofrequency ablation in a porcine model at various power levels, which can potentially assist operators in delineating a precise ablation field and providing effective thyroid ablation treatment safely.

Radiofrequency Ablation for Recurrent Thyroid Cancers: 2025 Korean Society of Thyroid Radiology Guideline

Radiofrequency ablation (RFA) is a minimally invasive treatment modality used as an alternative to surgery in patients with benign thyroid nodules, recurrent thyroid cancers (RTCs), and primary thyroid microcarcinomas. The Korean Society of Thyroid Radiology (KSThR) initially developed recommendations for the optimal use of RFA for thyroid tumors in 2009 and revised them in 2012 and 2017. As new meaningful evidence has accumulated since 2017 and in response to a growing global interest in the use of RFA for treating malignant thyroid lesions, the task force committee members of the KSThR decided to update the guidelines on the use of RFA for the management of RTCs based on a comprehensive analysis of current literature and expert consensus.

Long-term clinical outcomes of thermal ablation for benign thyroid nodules and unresolved issues: a comprehensive systematic review

Thermal ablation is widely accepted as an effective and safe method for treating benign thyroid nodules. Many studies reporting short-term results have consistently demonstrated the efficacy and safety of thermal ablation. However, as the clinical application of thermal ablation grows and follow-up periods extend, long-term clinical outcomes of thermal ablation have revealed several issues, including regrowth and diagnosis of malignancy in ablated lesions. In this systematic review, we analyze the long-term clinical outcomes of thyroid thermal ablation, focusing on regrowth, delayed surgery, and the potential for malignancy after thermal ablation and propose solutions to address these unresolved issues and enhance the management of benign thyroid nodules through thermal ablation.

Early second radiofrequency ablation treatment gave rise to significantly greater nodule shrinkage at 12 months than single-session treatment for large-volume benign thyroid nodules

INTRODUCTION

Radiofrequency ablation (RFA) is an effective nonsurgical treatment for symptomatic benign thyroid nodules. Large-volume nodules (≥20-mL) often require 2 or more radiofrequency ablation sessions to achieve desirable shrinkage but the optimal interval between sessions remains unknown. We hypothesized that early (within 6 months) retreatment could improve nodule shrinkage. This study compared the 12-month volume reduction rate (VRR) and complications between single-session radiofrequency ablation and 2-session radiofrequency ablation within 6 months for large benign thyroid nodules.

METHODS

Consecutive patients with cytologically proven benign thyroid nodules ≥20 mL undergoing radiofrequency ablation were prospectively assigned to undergo either single-session (group 1) or 2-session radiofrequency ablation within 6 months (group 2). All were followed up for at least 12 months after the initial radiofrequency ablation. Volume reduction rate was calculated as (baseline - current volume)/baseline volume × 100%. Complications were documented.

RESULTS

Out of 67 nodules ≥20 mL that underwent radiofrequency ablation, 43 nodules (group 1: n = 23, group 2: n = 20) from 42 patients were analyzed. Both groups had comparable baseline nodule volumes (33.2 ± 14.9 mL vs 34.3 ± 12.5 mL) and clinical parameters (P > .05). The 6-month volume reduction rate was comparable (65.7 ± 13.2% vs 68.6 ± 13.3%, P = .264) but the 12-month volume reduction rate was significantly greater in group 2 (65.9 ± 17.1% vs 75.6 ± 11.5%, P = .019). Group 2 nodules continued to shrink from 6 to 12 months (P = .012), whereas group 1 nodules did not (P = .503). Two-session radiofrequency ablation within 6 months was the only significant factor associated with a 12-month volume reduction rate of ≥75% (odds ratio 4.375, 95% confidence interval 1.210-15.812, P = .024). No vocal cord paresis or hematoma requiring reoperation occurred.

CONCLUSION

Early retreatment with 2-session radiofrequency ablation within 6 months was safe and led to significantly greater nodule shrinkage at 12 months than single-session radiofrequency ablation.

Is ultrasound-guided radiofrequency ablation a reliable treatment option for unifocal T1aN0M0 papillary thyroid carcinoma in the isthmus: a retrospective comparative study based on large-sample data

OBJECTIVE

To evaluate whether ultrasound-guided radiofrequency ablation (RFA) is reliable for unifocal T1aN0M0 papillary thyroid carcinoma in the isthmus (PTCI).

METHODS

431 patients who underwent ultrasound-guided RFA for unifocal T1aN0M0 papillary thyroid carcinoma (PTC) were divided by location of the lesion into the PTCI group (52 females, 7 males, mean age 43.79 ± 12.04 years, range 22-74 years) and the PTCL group ((291 females, 81 males, mean age 43.42 ± 10.87 years, range 18-75 years) for comparative analysis. The efficacy of ultrasound-guided RFA was evaluated by volume reduction rate (VRR), complete disappearance rate (CDR) and disease progression, and the safety was evaluated by incidence of complications.

RESULTS

The two groups exhibited a consistent trend of change, with the PTCI group performing better in volume, VRR and CDR at all follow-up time points expect 1 month, but the differences were not statistically significant (p > 0.05). The mean initial volume of the PTCI group vs the PTCL group decreased significantly from 65.4 ± 69.79 vs 86.38 ± 87.09 mm³ (range 10.92-427.58 vs 3.05-471.6 mm³) to 0 vs 0 mm³ at a mean follow-up time of 31.12 ± 12.5 months (range 12-60 months); their VRR increased significantly from -618.62 ± 655.61% vs -789.85 ± 1135.07% at 1 month to 100% vs 100% at 48 months. No disease progression was found in the two groups. The PTCI group had no complications, whereas the PTCL group had a total of 7 complications (1.88%).

CONCLUSIONS

Ultrasound-guided RFA is reliable for unifocal T1aN0M0 PTCI. It can be promoted as an alternative to immediate surgery for selected PTC patients.

Impact of thyrotropin levels on outcomes in T1N0M0 papillary thyroid cancer after microwave ablation

OBJECTIVE

To evaluate the impact of thyroid-stimulating hormone (TSH) levels on tumor progression and survival in patients with uni- and multifocal T1N0M0 papillary thyroid cancer (PTC) treated with microwave ablation (MWA).

METHODS

This retrospective study analyzed the records of 525 patients with uni- and multifocal T1N0M0 PTC who underwent MWA from January 2015 to December 2022. Patients were stratified into uni-focal (U-PTC) and multifocal (M-PTC) groups and further categorized based on post-ablation TSH levels into low (≤1 mU/L), medium (1-2 mU/L), and high (>2 mU/L) subgroups. The tumor progression rates and progression-free survival were assessed.

RESULTS

In U-PTC patients, lower TSH levels were significantly associated with higher tumor progression rates (10.1%) compared to those in the medium (2.9%) and high (2.1%) TSH groups (p = .009). Conversely, in M-PTC patients, tumor progression rates did not vary significantly across TSH levels. Progression-free survival rates in U-PTC patients were notably lower at the 5-year mark in the low TSH group (85.7%) compared to the medium TSH group (96.5%, p = .046). However, progression-free survival rates in M-PTC patients showed convergence across all TSH levels by the 5-year follow-up.

CONCLUSION

Maintaining TSH levels within the normal range post-ablation may be appropriate for managing T1N0M0 PTC treated with MWA, but randomized controlled trials are needed to confirm optimal TSH targets and their impact on outcomes.

Successful Multimodal Treatment of Locally Advanced Parathyroid Carcinoma

Parathyroid carcinoma is a rare endocrine malignancy for which the primary treatment is surgery; however, 50% of the patients develop local recurrence or distant metastases. No consensus exists on the standard treatment for metastatic parathyroid cancer. Here we report a case of a 41-year-old male with inoperable locally advanced parathyroid carcinoma who was successfully treated with multimodal therapy including radiofrequency ablation (RFA), external beam radiation therapy (EBRT) to the neck, and sorafenib. Eleven months after initiating sorafenib, serum calcium levels were normal, and both the intact PTH level and the size of metastatic lesion remained stable; thus, we decided to discontinue sorafenib. After discontinuation, the disease remained stable for 18 months and continues to be so. Hence, clinicians can consider multimodal treatment with RFA, EBRT, and sorafenib as a treatment option for locally advanced parathyroid carcinoma.

Role of Locoregional Therapies in the Treatment of Thyroid Pathology: Proceedings from the Society of Interventional Radiology Foundation Research Consensus Panel

The role of locoregional therapy in the management of thyroid pathology is rapidly evolving. The Society of Interventional Radiology (SIR) Foundation commissioned an international research consensus panel consisting of physicians from multiple disciplines with expertise in the management of benign and malignant thyroid disease. The panel focused on identifying gaps in the current body of literature to establish research priorities that have the potential to shape the landscape of minimally invasive thyroid interventions. The topics discussed were centered on the emerging role of ablation for malignant thyroid tumors and the treatment of large functioning nodules with embolization and ablation. Specifically, the panel prioritized identifying nodule characteristics, including size and location, that are associated with ideal outcomes following thermal ablation for papillary thyroid microcarcinoma through the development of an international registry or a prospective, multi-institutional trial. The panel also prioritized evaluating the role of locoregional therapy in Stage T1b papillary thyroid cancer through a sequence of 2 studies: (a) a Phase I study of ablation followed by immediate resection of Stage T1b papillary thyroid cancer, which may lead to (b) a Phase II prospective, multi-institutional study of ablation followed by biopsy for Stage T1b papillary thyroid cancer. Lastly, the panel prioritized investigating the treatment of large, functioning thyroid nodules >20 mL in volume through a randomized clinical trial or prospective registry comparing embolization alone with embolization followed by ablation.

Efficacy of Radiofrequency Ablation in Autonomous Functioning Thyroid Nodules: A Comprehensive Systematic Review and Meta-analysis

BACKGROUND

Radiofrequency ablation (RFA) is a minimally invasive outpatient procedure that has recently emerged as a treatment option for autonomous functioning thyroid nodules (AFTNs), offering a less invasive alternative to surgery. The objective of this systematic review and meta-analysis is to evaluate the efficacy of RFA for AFTNs.

METHOD

Global databases of PubMed, Scopus, Embase, Web of Science, and Cochrane Library were systematically searched from 1990 until January 5, 2024, for studies on AFTNs undergoing RFA that presented volume reduction ratio (VRR) for at least one of 1, 3, 6 or 12 months post-operative follow-up with the results presented as means. The primary outcomes were VRR and TSH normalization rate, and the secondary outcomes were the cosmetic score, symptom score, and post-procedure complications. Heterogeneity was assessed by Cochrane and I2 statistics, and a random-effects model was used for meta-analysis. The study protocol was registered on PROSPERO (CRD42024499932).

RESULTS

A total of 10 eligible studies with a total sample size of 254 were included. The pooled VRR after 1, 3, 6, and 12 months of follow-up post-treatment with RFA was 46.6% (95% CI: 40.3-52.9%), 62% (95% CI: 57.6-66.4%), 67.4% (95% CI:62.3-72.6%), and 77.2% (95% CI: 79.2-81.5%), respectively. The overall rate of TSH normalization was 76.4% (95% CI: 58.1-88.4%). Based on included studies the overall rate of subclinical hypothyroidism as one of the most important side effects of this method was 4% (95% CI: 1.9%-8.1%).

CONCLUSION

RFA emerges as a promising non-surgical treatment for AFTNs, showing high rates of TSH normalization, tumor size reduction, and improved cosmetic and symptom scores. However, further research is needed to compare RFA with surgical methods and assess long-term outcomes.

Thermal Ablation for Papillary Thyroid Carcinoma

Importance

Image-guided thermal ablation has been administered for patients with T1N0M0 papillary thyroid carcinoma (PTC) who elect to not undergo surgery or receive active surveillance. Considering the indolent nature of PTC, long-term outcomes of ablation are needed.

Objective

To investigate l0-year outcomes of thermal ablation in treating T1N0M0 PTC.

Design, Setting, and Participants

This multicenter study was conducted at 4 university-affiliated hospitals in China and included 179 consecutive patients with T1N0M0 PTC (median [IQR] volume, 88.0 [163.2] mm3) who underwent thermal ablation between June 2010 and March 2014. Patients who were ineligible to undergo surgery or elected not to were included, and patients had PTC tumors that were smaller than 20 mm as confirmed by biopsy; no clinical or imaging evidence of extrathyroidal extension, lymph node metastasis (LNM), or distant metastasis; and no history of neck irradiation.

Main Outcomes and Measures

The primary outcomes were disease progression (LNM, newly developed tumors, persistent tumors, and distant metastasis) and disease-free survival (DFS). Secondary outcomes were technical success, volume reduction rate, tumor disappearance, complications, and delayed surgery. DFS was calculated using a Kaplan-Meier analysis.

Results

Among the 179 patients, the mean (SD) age was 45.8 (12.7) years, and 118 (65.9%) were female. During a mean (SD) follow-up period of 120.8 (10.8) months, disease progression was found in 11 of 179 patients (6.1%), including LNM in 4 patients (2.2%), newly developed tumors in 6 patients (3.3%), and persistent tumor in 1 patient (0.6%). The 10-year DFS was 93.9%. The technical success, median volume reduction rate, and tumor disappearance rate was 100%, 100%, and 97.2%, respectively. The magnitude of the disease progression (6.1% vs 7.1%; difference, 1.0%; 95% CI, -6.5% to 25.6%) and DFS (93.9% vs 92.9%; difference, 1.0%, 95% CI, -6.5% to 25.6%) between patients with T1a and T1b tumors was small. The difference in the rate of tumor disappearance between T1a and T1b tumors was large (99.4% vs 71.4%; difference, 28.0%; 95% CI, 10.9%-54.0%). One patient experienced transient voice hoarseness (0.6%). Because of anxiety, 1 patient underwent delayed surgery (0.6%).

Conclusions and Relevance

The results of this 10-year multicenter cohort study suggest that thermal ablation is an effective and safe alternative for patients with T1N0M0 PTC who do not undergo surgery or receive active surveillance. For safe and effective treatment, accurate radiologic evaluation, an understanding of ablation techniques, and experienced physicians are recommended.

Correlation Between Anxiety and Serum Thyroid Hormone Levels in Patients With Papillary Thyroid Carcinoma Undergoing Microwave Ablation

Objective: This study aims to explore the correlation between anxiety and serum thyroid hormone levels in patients with papillary thyroid carcinoma (PTC) who underwent microwave ablation (MWA). Methods: A total of 107 PTC patients who underwent MWA were recruited. Three months after MWA, serum samples were collected from each participant to analyze their thyroid-related hormone levels, including free T3 (FT3), free T4 (FT4), T3, T4, and thyroid-stimulating hormone (TSH) levels. Additionally, the Self-Rating Anxiety Scale (SAS) was used to measure anxiety levels at the same time. Linear correlation analysis was used to determine the correlation between anxiety and serum thyroid hormone levels. Results: SAS scores among the 107 PTC patients ranged from 27 to 58, with an average score of 38.19 ± 6.68. Seven patients (6.54%) met the criteria for anxiety; the mean SAS score among these patients was 51.57 ± 2.88. The remaining 100 patients (93.46%) did not meet the criteria for anxiety; the mean SAS score among these patients was 37.04 ± 5.49. Among all participants, TSH levels varied from 0.30 to 5.09, with an average of 2.08 ± 0.91. Nine participants exhibited slight fluctuations in FT3, FT4, T3, T4, and TSH levels; these hormone levels consistently remained within the normal range for the other 98 patients. Linear correlation analysis revealed a significant positive correlation between anxiety and TSH levels (p < 0.001). Conclusion: The results demonstrated a significant positive correlation between anxiety and TSH levels in patients with PTC post-MWA, indicating that increased anxiety is associated with increased TSH levels.

Exploring Radiofrequency Ablation for T1 Papillary Thyroid Cancer in the United States: Mayo Clinic Experience

OBJECTIVE

To report the efficacy, safety, and feasibility of radiofrequency ablation (RFA) for T1 papillary thyroid carcinoma (PTC) in a large referral center in the United States.

PATIENTS AND METHODS

We conducted a retrospective study of 8 patients who underwent RFA for T1 PTC at Mayo Clinic in Rochester Minnesota, between July 1, 2020, and February 28, 2023. The RFA technique and the type of anesthesia are described. Thyroid function, changes in ablated zone, and adverse events were analyzed for up to 24 months after the procedure.

RESULTS

Of the 8 patients included in the study, 7 were female and 1 was male with a mean ± SD age of 53±16.4 years. Thyroid status was unaffected in 7 of the 8 patients. The median duration of RFA was 6 minutes (range, 2 to 14.5 minutes) with energy delivered at between 25 and 45 W. The mean ± SD volume of small PTCs was 0.3±0.2 mL, and the mean largest diameter was 9.5±3.3 mm (range, 6 to 15 mm). The mean ± SD ablated volume at 3 to 6 months was larger than the target lesion (0.8±0.7 mL), with a reduction in mean ± SD ablated volume of 0.4±0.4 mL at 7 to 12 months and 0.1±0.06 mL at 13 to 18 months. The ablated zone almost disappeared at 19 to 24 months (0.04±0.04 mL). There were no major adverse events during or after the RFA procedure.

CONCLUSION

This is the first reported series of T1 PTC treated with RFA in the United States. Early postablation imaging revealed that the ablated region was larger than the target lesions, followed by a serial decrease in size. Therefore, RFA at centers with such expertise appears to be a safe and effective treatment for small PTCs. Further studies are needed to evaluate its long-term efficacy and the risk of recurrence.

Risk factors for recurrent laryngeal nerve injury in microwave ablation of thyroid nodules: A multicenter study

BACKGROUND AND PURPOSE

This study aimed to investigate the risk factors for recurrent laryngeal nerve (RLN) injury after microwave ablation (MWA) of thyroid nodules and to identify factors influencing the recovery time of post-procedure hoarseness.

MATERIALS AND METHODS

We retrospectively analyzed data from patients who underwent MWA for thyroid nodules at five hospitals between November 2018 and July 2022. Patients were divided into malignant and benign nodule groups. Variables analyzed included nodule size and location, the shortest distance from nodules to the thyroid capsule and tracheoesophageal groove (TEG-D), and ablation parameters. Univariate and multivariate analyses were performed to identify risk factors. Kaplan-Meier and Cox analyses were used to evaluate the recovery time of hoarseness after MWA.

RESULTS

The study included 1,216 patients (mean age 44 ± 12 [SD] years; 901 women) with 602 malignant nodules and 614 benign nodules. The posterior capsule distance (PCD) and TEG-D were identified as independent influencing factors for hoarseness in all patients (P = 0.014, OR = 0.068; P < 0.001, OR = 0.005; AUC = 0.869). TEG-D was a significant risk factor for hoarseness, with safe thresholds identified at 4.9 mm for malignant nodules and 2.2 mm for benign nodules. Among patients who developed hoarseness, those in the close-distance group (TEG-D≤2 mm) had a longer recovery time compared to the distant-distance group. TEG-D was an independent factor influencing recovery time (P = 0.008, HR = 11.204).

CONCLUSION

Clinicians should consider several factors, particularly TEG-D and PCD, when assessing the risk of RLN injury before MWA. TEG-D was a vital independent factor influencing recovery time.

SUMMARY

Clinicians should pay attention to several influencing factors for RLN injury before MWA and TEG-D was an independent influencing factor for recovery time of hoarseness after MWA.

Thermal ablation for Bethesda III and IV thyroid nodules: current diagnosis and management

The diagnosis and management of Bethesda III and IV thyroid nodules remain clinical dilemmas. Current guidelines from academic societies suggest active surveillance or diagnostic lobectomy. However, the extent of surgery is often inappropriate, and a considerable percentage of patients experience under- or over-treatment. Thermal ablation has gained popularity as a safe and effective alternative treatment option for benign thyroid nodules. This review explores the feasibility of thermal ablation for Bethesda III or IV thyroid nodules, aiming to preserve the thyroid organ and avoid unnecessary surgery. It emphasizes individualized management, the need to consider factors including malignancy risk, clinical characteristics, and sonographic features, and the importance of supplemental tests such as repeat fine needle aspiration cytology, core needle biopsy, molecular testing, and radioisotope imaging.

Trends in thyroid function following radiofrequency ablation of benign, nonfunctioning thyroid nodules: A single institution review

BACKGROUND

Radiofrequency ablation (RFA) effectively reduces volume and improves symptoms of benign, non-functioning thyroid nodules (NFTNs). Given RFA's unclear impact on thyroid function, we examined post-RFA trends in thyroid hormones and antibodies.

METHODS

A retrospective cross-sectional analysis was conducted of patients treated at Columbia University with RFA for benign NFTNs between August 2019 and July 2023. Thyroid function tests were recorded pre-RFA and repeated 3, 6, and 12 months post-RFA.

RESULTS

We analyzed 185 patients with 243 benign NFTNs who underwent RFA. Volume reduction ratio increased post-RFA. Mean TSH increased to 2.4 mlU/L (p ​= ​0.005) at 3 months post-RFA and decreased to 1.8 mlU/L (p ​= ​0.551) by 12 months post-RFA. Tg and TPO antibody levels peaked at 6 months post-RFA (103.1 IU/mL, p ​= ​0.868 and 66.6 IU/mL, p ​= ​0.523, respectively).

CONCLUSIONS

With expected volume reduction post-RFA, we observed transient relative hypothyroidism as well as transient increases in thyroid antibodies, with normalization of these changes within 12 months.

Outcomes of Radiofrequency Ablation for Autonomously Functioning Thyroid Adenomas-Mayo Clinic Experience

Background

Autonomously functioning thyroid nodules (AFTNs) constitute 5% to 7% of thyroid nodules and represent the second most common cause of hyperthyroidism following Graves' disease. Currently, radioactive iodine (RAI) and surgery are the standard treatment options, and both incur a risk of postprocedural hypothyroidism and other surgery and radiation-related complications.

Methods

This work aimed at assessing the efficacy of radiofrequency ablation (RFA) as an alternative treatment option for resolving hyperthyroidism and the nodule volume rate reduction (VRR) and its associated adverse events.

Results

A total of 22 patients underwent RFA for a solitary AFTN. Seventy-two percent (n = 16) had subclinical hyperthyroidism, 9% (n = 2) had overt hyperthyroidism, and 18% (n = 4) were biochemically euthyroid on antithyroid medication. Average pretreatment TSH was 0.41 mIU/L (SD = 0.98) and free T4 1.29 ng/dL (SD = 0.33). Following a single RFA session, hyperthyroidism resolved in 90.9% (n = 20) and average VRR (61.13%) was achieved within 3 to 6 months following the ablation. Except for 1 nodule, none of the nodules grew during the follow-up period (16.5 months). Two patients (9%) developed transient tachycardia requiring short-term beta-blocker therapy, and 2 developed mild hypothyroidism requiring levothyroxine therapy. Two patients developed recurrent hyperthyroidism and elected to undergo lobectomy and repeat RFA respectively. No serious adverse effects were noted in this cohort.

Conclusion

RAI and/or surgery represent the standard of care for toxic adenomas, but RFA shows excellent efficacy and safety profile. Therefore, at centers with RFA expertise, it should be considered an alternative treatment strategy, avoiding radiation and surgery-related complications.

Ultrasound-guided ablation for T1N0M0 papillary thyroid carcinoma adjacent and non-adjacent danger triangle area: a retrospective comparative study

OBJECTIVES

To compare the safety and efficacy of ultrasound-guided radiofrequency ablation (RFA) in the treatment of T1N0M0 papillary thyroid carcinoma (PTC) with adjacent and non-adjacent danger triangle area (DTA).

MATERIALS AND METHODS

This retrospective study involved collecting clinical data of all T1N0M0 PTC patients who underwent RFA between January 2018 and December 2020 at the hospital. A total of 211 patients were enrolled in the study (mean age 43.25 ± 12.30 years, male-to-female ratio = 1:3). Among them, 91 had adjacent DTA involvement, while 120 had non-adjacent DTA involvement. Comparisons were made between the two groups patients regarding tumor volume changes, technical success rates, tumor disappearance, disease progression, complications.

RESULTS

In both groups, the technical success rate was 100%, with a median follow-up period of 30 months. The rates of complete tumor disappearance were 78% (71/91) and 74.2% (89/120) for the adjacent and non-adjacent DTA(p = .517). Disease progression rates were 2.2% (2/91) and 1.7% (2/120) (p > .99), Complication rates were 3.3%(3/91) in the adjacent DTA group and 1.7% (2/120) in the non-adjacent DTA group (p = .654). At 6th month after ablation, the volume reduction rate (VRR) in the non-adjacent DTA group (42.3%) was higher than in the adjacent DTA group (37.3%) (p = .002). However, no significant differences were observed in VRR between the two groups at 1, 3, 12, 18, 24, 30, and 36 months (p > .05).

CONCLUSION

In the treatment of T1N0M0 PTC, the complication rates and short-term efficacy of RFA in adjacent to the DTA did not differ from those of non-adjacent DTA.

Efficacy of microwave ablation in the treatment of large benign thyroid nodules: a multi-center study

OBJECTIVE

To evaluate the efficacy, safety, and improvement of symptoms by ultrasound-guided microwave ablation (MWA) for patients with large benign thyroid nodules (BTNs).

METHODS

Eighty-seven patients with 87 BTNs (≥ 4 cm) treated with MWA between April 2015 and March 2021 were enrolled in this retrospective multicenter study, with clinical and ultrasound examinations performed at the 1st, 3rd, 6th, and 12th months. A multivariable linear mixed effects model was employed to explore the alterations in volume and volume reduction ratio (VRR), as well as the potential factors associated with VRR.

RESULTS

The mean age of the 87 patients was 45.69 ± 14.21 years (range 18-76 years), and the ratio of men to women was 1:4.8. The mean volumes were much decreased at the 12th month after ablation compared to the initial volumes (p < .001). The mean VRR was 76.09% at the 12th month. The technique efficacy (VRR > 50%) was 90.80% at the 12th month. A multivariate analysis revealed that VRR was related to the initial volume (p = .015), annular flow (p = .010), and nodule composition (p = .024). The mean symptomatic score decreased from 4.40 ± 0.28 to 0.26 ± 0.06 at the 12th month (p < .001). At the same time, the mean cosmetic score decreased from 3.22 ± 0.10 to 1.31 ± 0.08 (p < .001).

CONCLUSION

MWA could serve as a safe and effective therapy for large BTNs, significantly reducing the volume of BTNs and significantly improving compressive symptoms and appearance problems.

CLINICAL RELEVANCE STATEMENT

Microwave ablation could serve as a safe and effective therapy for large benign thyroid nodules, leading to significant volume reduction and satisfied symptom and cosmetic alleviation period.

KEY POINTS

• This multicenter study investigated the feasibility and safety of microwave ablation for large benign thyroid nodules. • After ablation, the nodule volume was significantly reduced, and patients' symptoms and appearance problems were significantly improved. • Microwave ablation is feasible for large benign thyroid nodules and has been a supplement treatment.

Microwave versus Radiofrequency Ablation in Treating Predominantly Solid Benign Thyroid Nodules: A Randomized Controlled Trial

Background Current guidelines recommend radiofrequency ablation (RFA) as the first-line treatment for benign thyroid nodules. Purpose To compare the efficacy and safety of microwave ablation (MWA) and RFA for the treatment of predominantly solid benign thyroid nodules. Materials and Methods This prospective, randomized, open-label, multicenter study was conducted from August 2019 to February 2023. Participants with nonfunctioning, predominantly solid benign thyroid nodules from five institutions were randomly assigned with a 1:1 ratio to receive MWA or RFA treatment. Participants were followed up for at least 2 years. Primary outcomes were 6-month and 2-year volume reduction rate (VRR) of nodules after ablation. Secondary outcomes included VRR change over time, complications, and technique efficacy (defined as volumetric reduction ≥ 50% of the initial nodule volume). Continuous variables and categorical variables were compared using the t test and the χ2 test or Fisher exact test, respectively. Results This study included 76 participants in the MWA group (mean age, 46 years ± 12 [SD]; 58 female participants) and 76 in the RFA group (mean age, 50 years ± 13; 56 female participants). MWA was noninferior to RFA in terms of 6-month (mean difference, -5.6%; P = .01) and 2-year (-2.4%; P < .001) VRR after ablation. Comparing MWA and RFA, no evidence of a difference was observed for VRR change over time (mean difference from mixed-effects analysis, 6.9% [95% CI: -0.5, 13.9]; P = .73) or technique efficacy (91% vs 86%; P = .40). The most common major complication was voice change, which occurred in 6.6% of participants in the MWA group and 1.3% of participants in the RFA group (P = .21). Conclusion MWA and RFA showed comparable efficacy for treating participants with predominantly solid benign thyroid nodules. However, a larger sample size is needed to demonstrate that safety is comparable between the procedures. ClinicalTrials.gov Identifier: NCT04046354 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by McGahan in this issue.

[Local ablative procedures for treatment of thyroid nodules]

Thyroid nodules are very frequent in the iodine deficiency regions of central Europe and some of the affected patients are referred for definitive treatment, such as surgery and radioiodine treatment. In recent years nonsurgical and non-radioiodine techniques have been introduced to treat thyroid gland pathologies. These techniques include the probe-based techniques of radiofrequency, microwave and laser application. The only noninvasive technique is high-intensity focused ultrasound. All mentioned techniques have the goal to reduce the volume of the thyroid nodule by application of energy/heat. The knowledge of all techniques and their advantages and risks is necessary to help physicians and patients in making decisions for the appropriate method of treatment of thyroid nodules.