Radiofrequency ablation of benign thyroid nodules: recommendations from the Asian Conference on Tumor Ablation Task Force

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.

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.

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.

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.

Surgical and Pathological Challenges in Thyroidectomy after Thermal Ablation of Thyroid Nodules

Background: Thermal ablation is a minimally invasive treatment for benign thyroid nodules, but its impact on subsequent thyroidectomy and pathological evaluation is uncertain. This study investigates whether preoperative ablation complicates thyroidectomy and poses challenges for pathological diagnosis. Study Design: This retrospective cohort study used prospectively collected institutional registry data on patients with benign thyroid nodules who underwent thyroidectomy after prior radiofrequency ablation. Perioperative outcomes, including thyroidectomy difficulty scale (TDS) and macroscopic adhesion score (MAS), were compared with a control group without prior ablation. Histopathological and cytological changes within the ablated zone and periphery were also evaluated. Results: This study included 165 patients, with 145 in the nonablation group and 20 in the postablation group (17 females, mean age 53.4 years, mean nodule size 4.4 cm, mean interval between ablation and thyroidectomy 29.5 months). Compared with the nonablation group, the ablation group had longer operative time (99.5 vs. 69.5 minutes, p < 0.05), higher TDS (9 vs. 6, p < 0.05), more severe MAS (anterior 50.0% vs. 16.6%, p < 0.05; posterior: 35.0% vs. 16.6%, p < 0.05), and increased incidental parathyroidectomies (10.7% vs. 1.6%, p < 0.05). Histopathologically, the ablated area showed acellular hyalinization (95%), coagulative necrosis (60%), and chronic inflammation (85%). Both central and peripheral regions displayed cytological alterations (nuclear enlargement, focal chromatin clearing, and clear-cell change). Challenges in defining tumor capsule integrity were noted in eight follicular neoplasms, complicating the diagnosis of three follicular carcinomas and two follicular tumors of uncertain malignant potential. Conclusions: Thermal ablation of thyroid nodules may be associated with increased surgical difficulty and adhesion formation during subsequent thyroidectomy. Additionally, ablation-induced tissue alterations can potentially complicate pathological diagnosis. However, due to the small number of study cases, further confirmatory research is needed.

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.

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.

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.

Long-term outcomes of radiofrequency ablation for intrathoracic goiter up to 5 years: evaluated by computed tomography/magnetic resonance imaging and ultrasound

OBJECTIVES

This study evaluated the long-term efficacy and safety of radiofrequency ablation (RFA) for intrathoracic goiter (ITG) over a follow-up period exceeding six months.

METHODS

From 2017 to 2022, 22 patients (6 males, 16 females) with 24 ITGs treated with RFA at a single medical center were evaluated. All patients underwent ultrasonography (US), computed tomography (CT), or magnetic resonance imaging (MRI) before RFA. Follow-up CT/MRI was performed six months after the initial RFA and then every 6-12 months. The primary outcomes measured were the degree of extension, goiter volume, volume reduction rate (VRR), tracheal deviation, and tracheal lumen. Additionally, we assessed the outcomes of single-session RFA (n = 16) vs. multiple sessions (n = 8) on goiters and explored the correlation between ITG volume measurements obtained using ultrasonography and CT/MRI.

RESULTS

The median follow-up period was 12 months (interquartile range: 6-36.8 months). At the last follow-up, the nodule volume measured by CT/MRI had significantly decreased (76.2 vs. 24.6 mL; p < 0.05), with a VRR of 64.6%. Patients who underwent multiple RFA sessions showed a significantly higher VRR than the single-session patients (63.8 vs. 80.1%, p < 0.05). The intraclass correlation between goiter volumes measured using US and CT/MRI was moderate.

CONCLUSION

This study affirms the long-term efficacy and safety of RFA for ITG, providing an alternative treatment for nonsurgical candidates. Multiple RFA sessions may be beneficial for achieving better volume reduction. Sole reliance on ultrasonography is inadequate; therefore, integrating CT/MRI is essential for accurate pre-RFA and follow-up assessments.

Radiofrequency ablation compared to surgery for thyroid nodules: A case for office based treatment

Objective

We aim to evaluate the safety and effectiveness of radiofrequency ablation (RFA) for benign thyroid nodules by ENT surgeons and to compare it to conventional hemithyroidectomy in the public healthcare, operating theater contained setting.

Methods

50 patients who underwent a single session of RFA for symptomatic benign thyroid nodules in Prince of Wales Hospital and Tseung Kwan O Hospital in Hong Kong from 2020 to 2022 were evaluated. Objective outcomes including nodule volume, volume reduction rate (VRR) and complications were recorded. Subjective response in the form of a 0-10 point scale for patient symptoms including obstructive, cosmetic, pain and satisfaction scores were collected.

Results

Significant reduction in mean VRR was found at 3, 6 and 12 months post treatment, accompanied by a significant reduction in the mean obstructive and cosmetic symptom scores. Comparing with conventional hemithyroidectomy, the RFA group had a significantly shorter mean procedure time and lower rate of complications. Estimated cost to patient for RFA was found to be less than half of that of hemithyroidectomy.

Conclusion

RFA is a safe and effective treatment modality for benign thyroid nodules by ENT surgeons with advantages of being a scarless local anesthetic procedure with shorter procedure time, lower complication rate and lower cost to patient compared to hemithyroidectomy. In Hong Kong, where most of the population is treated in the public sector, there are limited resources, often with high caseload burden and long operation waiting times. Therefore, RFA is an office-based treatment that serves as a valuable alternative to hemithyroidectomy for benign nodules, especially in lower resource settings.

Level of evidence

3.

Comparison of safety, efficacy, and patient satisfaction with thermal ablation versus endoscopic thyroidectomy for benign thyroid nodules in a propensity-matched cohort

BACKGROUND

Thyroid nodules (TNs) often require intervention due to symptomatic or cosmetic concerns. Radiofrequency ablation (RFA) has shown promise as a treatment option, offering potential advantages without neck scars. Recently, the scarless treatment alternative of transoral endoscopic thyroidectomy vestibular approach (TOETVA) has emerged. When surgery can be performed in a scarless manner, it remains unclear whether ablation is still the preferred treatment choice. This study aims to compare the safety, efficacy, and patient satisfaction of RFA and TOETVA.

STUDY DESIGN

A retrospective data analysis was conducted on patients treated with RFA or TOETVA for unilateral benign TNs between December 2016 and September 2021. Propensity score matching was employed to create comparable groups. Various clinicopathologic parameters, treatment outcomes, and costs were assessed.

RESULTS

Of the 2814 nonfunctional thyroid nodules treated during this period, 642 were benign and unilateral. A total of 121 and 100 patients underwent thermal ablation and transoral endoscopic thyroidectomy, respectively. After matching, 84 patients were selected for each group. Both RFA and TOETVA demonstrated low complication rates, with unique complications associated with each procedure. Treatment time (30.8±13.6 vs. 120.7±36.5 min, P <0.0001) was shorter in the RFA group. Patient satisfaction (significant improvement: 89.3% vs. 61.9%, P <0.0001) and cosmetic results (cosmetic score 1-2: 100.0% vs. 54.76%, P <0.0001) favored TOETVA. RFA was found to be less costly for a single treatment, but the cost of retreatment should be considered. The histological diagnoses post-TOETVA revealed malignancies in 9 out of 84 cases, underscoring the significance of follow-up assessments.

CONCLUSION

Scarless procedures, RFA and TOETVA, are effective for treating unilateral benign TNs, each with unique advantages and drawbacks. While RFA is cheaper for a single treatment, TOETVA offers superior cosmetic results and patient satisfaction. Further research is needed to evaluate long-term safety and cost-effectiveness. It is crucial to remain vigilant about the possibility of malignancy despite benign cytology pre-treatment.

Assessing the efficacy of thyroid nodule radiofrequency ablation using patient-reported outcome measures

BACKGROUND

Radiofrequency ablation has recently emerged as an alternative treatment for thyroid nodules. Most studies are centered on volume reduction, whereas a few have assessed symptom improvement mainly with nonstandardized metrics. As experience in the United States is growing, we aim to assess the efficacy of radiofrequency ablation in treating benign thyroid nodules using the validated Patient-Reported Outcomes Measurement for Parathyroid and Thyroid Disease.

METHODS

This is a prospective study of a newly established radiofrequency ablation program at a single tertiary referral center in 2022. Patients who underwent radiofrequency ablation were evaluated using the Patient-Reported Outcomes Measurement for Parathyroid and Thyroid Disease, a validated metric ranging from 0 to 100 at baseline, 2 weeks, 3 months, and 6 months. In addition, a thyroid ultrasound was done at those intervals to assess size and volume reduction. Procedure complications were evaluated as well.

RESULTS

A total of 25 patients underwent radiofrequency ablation during the study period for a total of 32 nodules treated; 84% were female with a mean age of 51 years. The baseline mean nodule volume and largest dimension were 13 ± 11 mL and 3.4 ± 1 cm, respectively. A significant change in the Patient-Reported Outcomes Measurement for Parathyroid and Thyroid Disease compressive score was seen at 3 months (38.9 ± 26.4 to 21.0 ± 21.4; P = .004) and 6 months (32.7 ± 19.9 to 17.5 ± 21.0; P = .02) but not at 2 weeks (41.0 ± 22.7 to 36.1 ± 21.9; P = .28). Significant volume and size reductions were seen at all 3-time points. Two complications occurred.

CONCLUSION

Our initial results of the thyroid radiofrequency ablation program find that it effectively alleviates symptoms by reducing nodule size in patients with symptomatic benign thyroid nodules.

Novel and Advanced Ultrasound Techniques for Thyroid Thermal Ablation

Thyroid radiofrequency ablation and microwave ablation are widely adopted minimally invasive treatments for diverse thyroid conditions worldwide. Fundamental skills such as the trans-isthmic approach and the moving shot technique are crucial for performing thyroid ablation, and advanced techniques, including hydrodissection and vascular ablation, improve safety and efficacy and reduce complications. Given the learning curve associated with ultrasound-guided therapeutic procedures, operators need training and experience. While training models exist, limited attention has been given to ultrasound maneuvers in ablation needle manipulation. This article introduces two essential maneuvers, the zigzag moving technique and the alienate maneuver, while also reviewing the latest ultrasound techniques in thyroid ablation, contributing valuable insights into this evolving field.

Radiofrequency ablation for thyroid nodules in Ecuador: a cross-sectional study

OBJECTIVES

To describe the demographic characteristics and clinical outcomes following the first cohort of patients with Bening Thyroid Nodule (BTN) and (Papillary Thyroid Microcarcinoma) (PTMC) treated with Radiofrequency Ablation (RFA)in Ecuador.

METHODS

Single-center, cross-sectional study. We included adults undergoing RFA for BTN and PTMC between July 2019 and May 2022. Descriptive statistics and the Wilcoxon signed-rank test were used to compare some pre- and post-intervention outcomes.

RESULTS

We included 44 patients with 36 BTNs and eight PTMCs. The median age was 45.80 years (IQR 16-79 years), and most patients had normal thyroid function (72.72%). The median follow-up time was 7.80 months (IQR1.0-34.0). Nodules were primarily solid (43.21%) or predominantly solid (56.81%). The pre-RFA median volume in the benign lesions group was 10.30 ml (IQR 1.86-18.97). After ablation, the 1-month, 3-month, 6-month, and 12-month median volumes were 6.90 (IQR 0.48-10.15; p < 0.01) mL, 5.72 (IQR 0.77-7.25; p = 0.045); 0.98 (IQR 0.25-3.64; p < 0.01), and 0.11 (IQR 0.07-11.26; p = 0.026), respectively. The volume rate reduction was 47.20%, 72.20%, 74.00%, and 96.20% at 1, 3, 6, and 12-month follow-ups, respectively. The pre-RFA median volume in the PTMC group was 0.25 ml (IQR 0.19-0.48). After ablation, the 1-month, 3-month, and 6-month mean volumes were 0.19 (range 0.12-0.31; p = 0.120) mL, 0.10 (IQR 0.05-0.15; p = 0.13), and 0.01 (IQR 0.005-0.04; p = 0.364), respectively.

CONCLUSIONS

In this first report from Ecuador, we found that RFA may be a feasible alternative for treating benign and malignant thyroid nodules in the short term. Long-term data are needed to evaluate oncologic outcomes in PTMC patients.

Development and preclinical evaluation of multifunctional hydrogel for precise thermal protection during thermal ablation

Image-guided thermal ablation (TA), which is less invasive, has been widely applied for treating various kinds of tumors. However, TA still poses the potential risk of thermal damage to sensitive tissue nearby. Therefore, an adjunctive thermoprotective hydrodissection technique with constant injection of 5% glucose (5% Glu) has currently been adopted for clinical application, but this may be hazardous to humans. In this study, a multifunctional hyaluronic acid-based hydrogel (HA-Dc) was developed for hydrodissection. Compared with 5% Glu (the most clinically used solution) and the previously reported F127 hydrogel, the HA-Dc hydrogel was studied in vitro in a porcine liver model and in vivo in a rabbit model and showed good injectability and better tissue retention, stability, and thermoprotective properties throughout the TA procedure. Furthermore, in the preclinical evaluation in a Macaca fascicularis (M. fascicularis) model, HA-Dc showed excellent performance in terms of stricter neuroprotection compared with 5% Glu. In addition, the HA-Dc hydrogel with good biocompatibility and controllable degradation behavior in vivo could be a promising platform for thermal protection during clinical TA procedures.

Factors Influencing a Favorable Outcome for RFA of Huge Benign Thyroid Nodules: Preliminary Results and Short-Term Evaluation

Objective

This study aimed to investigate potentially favorable factors influencing the therapeutic success of radiofrequency ablation (RFA) of huge benign thyroid nodules (BTNs) (volume >100 ml) and to evaluate the feasibility of RFA as an alternative treatment modality for patients unable or unwilling to undergo surgery.

Methods

This retrospective study evaluated a total of 868 patients, of which 22 patients had huge BTNs who underwent ultrasound-guided moving shot RFA treatment between May 2017 and January 2022. The huge BTNs were categorized into two groups according to a post-RFA treatment volume reduction ratio (VRR) of >80% and <80% at 6 months. Factors influencing these huge BTNs were reviewed, analyzed, and correlated with treatment effectiveness between the two groups.

Results

The factors influencing an effective VRR included huge BTNs located on the left side (OR 7.875, p = 0.03), predominant solid/spongiform nodules (OR 7.875, p = 0.03), and higher initial ablation rate (IAR) (p = 0.028). Multivariable logistic regression revealed predominant solid/spongiform nodule and the higher IAR were associated with the advanced VRR.

Conclusion

RFA was effective at decreasing the volume of huge BTNs with an acceptable complication rate. The BTN characteristics correlated with a better VRR at the 6-month short-term follow-up were predominant solid/spongiform BTNs and those with the first time ablation treatment initial ablation rate. Nevertheless, regarding the higher regrowth rate of these groups of patients who may need to be treated more times, RFA can only be a feasible alternative treatment modality for patients unable or unwilling to undergo operation.

[Effective and Safe Application of Radiofrequency Ablation for Benign Thyroid Nodules]

Radiofrequency ablation (RFA) has been a representative, non-surgical treatment for benign thyroid nodules that cause cosmetic problems or compression symptoms. The procedure of RFA should be performed effectively and safely. This review discusses the patient selection, pre-procedure evaluation and planning, principles, devices, techniques, and complications with reference to the guidelines and research on thyroid RFA. In particular, this review will devote to introduce RFA techniques and to provide practical help in the implementation of this procedure.

Delayed Cancer Diagnosis in Thyroid Nodules Initially Treated as Benign With Radiofrequency Ablation: Ultrasound Characteristics and Predictors for Cancer

OBJECTIVE

Regrowth after radiofrequency ablation (RFA) of symptomatic large thyroid nodules, initially treated as benign, sometimes turns out to be malignancies. This study aimed to assess the ultrasound (US) characteristics of thyroid nodules initially treated as benign with RFA and later diagnosed as cancers, predictive factors for cancers masquerading as benign, and methods to avoid RFA in these cancers.

MATERIALS AND METHODS

We reviewed the medical records of 134 consecutive patients with 148 nodules who underwent RFA between February 2008 and November 2016 for the debulking of symptomatic thyroid nodules diagnosed as benign using US-guided biopsy. We investigated the pre-RFA characteristics of the thyroid nodules, changes at follow-up after RFA, and the final surgical pathology.

RESULTS

Nodule regrowth after RFA was observed in 36 (24.3%) of the 148 benign nodules. Twenty-two of the 36 nodules were surgically removed, and malignancies were confirmed in seven (19.4% of 36). Of the 22 nodules removed surgically, pre-RFA median volume (range) was significantly larger for malignant nodules than for benign nodules: 22.4 (13.9-84.5) vs. 13.4 (7.3-16.8) mL (P = 0.04). There was no significant difference in the regrowth interval between benign and malignant nodules (P = 0.49). The median volume reduction rate (range) at 12 months was significantly lower for malignant nodules than for benign nodules (51.4% [0-57.8] vs. 83.8% [47.9-89.6]) (P = 0.01). The pre-RFA benignity of all seven malignant nodules was confirmed using two US-guided fine-needle aspirations (FNAs), except for one nodule, which was confirmed using US-guided core-needle biopsy (CNB). Regrown malignant nodules were diagnosed as suspicious follicular neoplasms by CNB. Histological examination of the malignant nodules revealed follicular thyroid carcinomas, except for one follicular variant, a papillary thyroid carcinoma.

CONCLUSION

Symptomatic large benign thyroid nodules showing regrowth or suboptimal reduction after RFA may have malignant potential. The confirmation of these nodules is better with CNB than with FNA.

History of Thyroid Ultrasound

From low-resolution images in the 1960s to current high-resolution technology, ultrasound has proven to be the initial imaging modality of choice for thyroid application. Point-of-care ultrasound has brought the technology to the thyroid specialist. Combined with physical examination, it provides real-time information regarding goiter, thyroid nodules, and thyroid cancer. Ultrasound-guided fine-needle aspiration biopsy has become the accepted norm, with biopsies rarely performed using palpation alone. Advantages of ultrasound-guided biopsy include precise placement of the needle within the nodule, selective sampling of areas with suspicious features, and accurate direction of the biopsy needle to actively growing viable cells in the periphery of the nodule. Education of endocrinologists in thyroid ultrasound began in the late 1990s and by 2016 more than 6000 clinicians had completed an ultrasound course. Concurrent with this rapid expansion of use of thyroid ultrasound was a rise in the diagnosis of small papillary carcinomas, which might have otherwise remained indolent and undetected. The 2009 American Thyroid Association Guidelines for the Management of Thyroid Nodules and Thyroid Cancer recommended biopsy for all solid hypoechoic nodules measuring larger than 1 cm. Attempting to decrease the frequency of biopsies of low-risk nodules, subsequent guidelines have focused on identifying and selectively biopsying those thyroid nodules at higher risk of clinically significant carcinoma based on ultrasound appearance. A major role for thyroid ultrasound has been in both preoperative staging and mapping to help determine the extent of surgery, as well as postoperative monitoring for locoregional soft tissue or lymph node metastases. With the recognition that the increase in papillary carcinoma was predominantly a result of early diagnosis of small often indolent cancers, active surveillance has become a promising management strategy for papillary thyroid microcarcinomas. Thyroid ultrasound is essential to active surveillance of thyroid cancer. Easy access to high-quality ultrasound studies is a requirement for a successful active surveillance program. Thyroid ultrasound has been used to facilitate interventional procedures, including treatment of thyroid nodules, treatment of recurrent thyroid cancer, and therapy of papillary thyroid microcarcinoma.

Radiofrequency versus Ethanol Ablation for Single-Session Treatment of Benign Cystic Thyroid Nodules: A Short-Term Retrospective Study

Objective

This study aims to compare 1-month's efficacy and safety of single-session ethanol ablation and radiofrequency ablation for treating both purely cystic nodules and predominantly cystic thyroid nodules.

Materials and methods

This short-term retrospective study was approved by the Ethics Committee of the Institutional Review Board of Danang Family hospital, and written informed consent for procedures was obtained for all patients. Thirty-nine patients who presented with cystic thyroid nodules and met inclusion criteria were extracted from the computerized medical records. The internal fluid of cystic thyroid nodules was aspirated as much as possible. Ethanol ablation was performed using 18-gauge needles with 99.5% ethanol, and RFA used a cooled-electrode RFA system and 18-gauge internally cooled electrodes via the trans-isthmic approach, moving-shot technique. Nodule volume, therapeutic success rate, the largest diameter, thyroid function tests, and complications were evaluated and compared before and after treatment in each group.

Results

Among 39 patients, 17 patients were undergone EA (mean age of 47.35 years; the proportion of female of 76.5%; purely thyroid cyst percentage of 41.4%) and 22 patients were undergone RFA (mean age of 46.63 years; the proportion of female of 86.4%; purely thyroid cyst percentage of 54.5%). Both treatment techniques showed a significant reduction of the largest diameter and nodule volume (p<0.05) without complications. RFA reduced nodule volume and the largest nodule size greater than EA treatment at 1-month post-ablation (p<0.05). In addition, the therapeutic success rate in the RFA group was higher than in the EA group.

Conclusion

Both RFA and EA treatment with single-session confirm the efficacy and safety for cystic thyroid nodules at 1-month follow-up, RFA reduced greater in nodule volume and the largest nodule size than the EA treatment. Thus, the therapeutic success rate in the RFA group was higher than in the EA group.

["Leverage pry-off method" for effective prevention of thermal injury during microwave ablation of benign thyroid nodules]

OBJECTIVE

To assess the safety and efficacy of"leverage pry-off method"for preventing thermal injury during microwave ablation of benign thyroid nodules.

METHODS

From July, 2017 to September, 2019, a total of 348 patients with benign thyroid nodules underwent ultrasound-guided microwave ablation. For protecting from thermal injury during the ablation, "hydrodissection technique" was used in 174 of the patients (admitted from July, 2017 to August, 2018) and "leverage pry-off method" in the other 174 patients (admitted from September, 2018 to September, 2019). All the patients were followed up for 1 to 12 months after the operation for observation of severe complications and nodular residues.

RESULTS

Ultrasound-guided microwave ablation was completed in all the 348 patients. The most common severe complication associated with the ablation was voice change, occurring in 3 cases (1.7%) in "hydrodissection technique" group and in 4 (2.3%) in the "leverage pry-off method" group, showing no significant difference between the two groups (P>0.05). During the follow-up, no significant difference was found in the rate of nodular residues between the "hydrodissection technique" group and "hydrodissection technique" group (9.8% vs 10.9% (P>0.05).

CONCLUSIONS

The "leverage pry-off method" is simple and effective for preventing thermal injury during microwave ablation of benign thyroid nodules.

[Does preoperative risk grading have clinical value for benign thyroid nodular ablation?]

OBJECTIVE

To explore the risk grading method for benign thyroid nodules before microwave ablation and the clinical significance of risk grading.

METHODS

This study was conducted among 527 patients undergoing ultrasound-guided microwave ablation of benign thyroid nodules between July, 2017 and December, 2020.Based on anatomic relationship of the thyroid nodules with the adjacent tissues, the ablation risk was classified into 4 levels: low, medium, high and extremely high risks.The incidence of severe complications and the rate of residual nodules following the ablation were recorded.

RESULTS

In the patients graded to have low, medium, high and extremely high preoperative risks, the incidences of severe complications following the ablation were 0%, 0.88%, 2.41% and 6.78%, respectively, showing no significant differences among the different risk groups (P > 0.05).The rates of postoperative residual nodules in the 4 risk groups were 1.59%, 6.14%, 14.43% and 71.19%, respectively, showing a significant difference between the low and medium risk groups and the high and extremely high risk groups (P < 0.001).

CONCLUSION

Preoperative risk grading for thyroid nodular ablation can be helpful for prevention of severe complications during ablation and prediction of residual nodules after ablation.

Residual, regrowth, and new growth of radiofrequency ablation for benign thyroid nodules of different volumes: two-year follow-up results

INTRODUCTION

Radiofrequency ablation (RFA) is recognized as an effective technique for the treatment of benign thyroid nodules (BTNs), although the long-term results are limited. This study aimed to evaluate the residual vital volume increase, regrowth, and new growth over a 2-year period after RFA among different nodule volume groups.

SUBJECTS AND METHODS

This retrospective study evaluated 135 patients with 153 BTNs who underwent ultrasound guided RFA. The BTNs were categorized into small (<10 mL), medium (10-30 mL), and large (>30 mL) according to the initial volume of BTNs prior to ablation. The volume changes of each nodule were analyzed at 1, 3, 6, 12 and 24 months after RFA. New growth was defined as the growth in volume not found in the early follow-up on ultrasonography.

RESULTS

The initial ablation ratio of all BTNs was 99.67%. The mean volume reduction ratio (VRR) of BTNs was 85.53% after 2-year follow-up. The small nodule group showed a lower VRR compared to the other two groups at the 1-month follow-up, and there was no difference of VRR at the subsequent follow-ups. The incidence of residual vital volume increase was 4.58%. The overall incidence of regrowth was 3.92% and the mean timing of regrowth was 16.71 months. New growth occurred in 18.95% of patients. No further treatment was required in the majority of cases.

CONCLUSION

RFA achieved a clinically relevant volume reduction in different sizes of single BTNs which persisted for at least 2 years, thereby preventing the need for retreatment.

Different effects of intravenous and local anesthesia in patients undergoing ultrasound-guided radiofrequency ablation of thyroid nodules: a prospective cohort study

PURPOSE

To compare the efficacy and safety of intravenous anesthesia (IV) with local anesthesia (LA) in patients undergoing ultrasound (US)-guided radiofrequency ablation (RFA) of thyroid nodules.

METHODS

50 patients with American Society of Anesthesiologists classification grades I-II undergoing US-guided thyroid RFA were enrolled and randomly (1:1) divided into IV (conscious sedation with Ramsay Sedation Scale [RSS] scores of 2-3 with an anesthesiologist) and LA (subcutaneous anesthesia with lidocaine without an anesthesiologist) groups. Pre-, intra- and post-procedural blood pressure (BP) (SBP₀/DBP₀, SBP₁/DBP₁, and SBP₂/DBP₂), intra- and post-procedural pain (NRS₁ and NRS₂), ablated area volume, treatment time and adverse events were analyzed and compared.

RESULTS

Age, sex, weight, number, nature, volume of nodules, and SBP₀/DBP₀ showed no difference between both groups. 11 and 0 patients' SBP₁/DBP₁ were elevated in the LA and IV groups. NRS₁ differed between both groups. 6 patients in the LA group had moderate or severe pain, but none in the IV group. No between-group difference in SBP₂/DBP₂, NRS₂, ablation completion rate and ablated volume was noted. The median procedure duration differed from 1109 (176) s in IV group and 723 (227) s in LA groups. There was no increased incidence of adverse events in IV group.

CONCLUSIONS

IV with RSS scores of 2-3 maintained intra-procedural BP and relieved intra-procedural pain better, without affecting the ablation efficacy and increasing complications. Despite increased treatment time, IV is a potential option for patients undergoing US-guided RFA of thyroid nodules.

Quality appraisal of clinical practice guidelines for the use of radiofrequency ablation in the treatment of thyroid nodules and cancer

INTRODUCTION

Radiofrequency ablation (RFA) has gained significant recent global interest in the treatment of benign thyroid nodules and thyroid cancer. It is a relatively new, minimally invasive, thermal ablation technique that is an alternative to surgery. Several clinical practice guidelines (CPGs), consensus statements, and recommendations currently exist for the use of RFA in the treatment of benign thyroid nodules and thyroid cancers. These documents have considerable variability amongst them, and to date, their quality and methodologic rigor have not been appraised.

OBJECTIVE

To identify and perform a quality appraisal of clinical practice guidelines for RFA in the treatment of benign thyroid nodules and thyroid cancer using the Appraisal of Guidelines for Research and Evaluation (AGREE II) tool.

METHODS

A comprehensive literature search was performed in MEDLINE (via PubMed), EMBASE, and SCOPUS databases from inception to November 1, 2021. Four reviewers independently evaluated each guideline using the AGREE II instrument. Scaled domain scores were generated and the threshold used for satisfactory quality was >60%. Additionally, intraclass correlation coefficients (ICCs) were calculated to determine level of agreement between reviewers.

RESULTS

Seven guidelines were selected for final evaluation based on inclusion/exclusion criteria. Two guidelines were classified "high" quality, one "average" quality, and the rest "low" quality. The "Clarity and Presentation" (65.68 ± 26.1) and "Editorial Independence" (61.32 ± 25.8) domains received the highest mean scores, while the "Applicability" (32.14 ± 22.8) and "Rigor of Development" (45.02 ± 29.8) domains received the lowest mean scores. ICC statistical analysis showed high magnitude of agreement between reviewers with a range of (0.722-0.944).

CONCLUSION

Reflecting upon our quality appraisal, it is evident that the quality and methodologic rigor of RFA guidelines can be improved upon in the future. Our findings also elucidate the existing variability/discrepancies amongst guidelines in the indications and use of RFA.

Recurrent Laryngeal Nerve Injury in Thermal Ablation of Thyroid Nodules-Risk Factors and Cause Analysis

CONTEXT

Recurrent laryngeal nerve (RLN) injury is a complication of thermal thyroid nodule treatment.

OBJECTIVE

We investigated the influencing factors of RLN injury in patients who underwent thermal ablation of thyroid nodules.

METHODS

The data of 1004 patients (252 male, 752 female; median age 44 years) who underwent thermal thyroid nodule ablation were retrospectively reviewed. Patients were divided into benign cystic, benign solid, and papillary thyroid cancer (PTC) groups. The parameters related to RLN injury were analyzed, including the largest diameter, location of the nodules, and shortest distance of the nodule to thyroid capsule and tracheoesophageal groove (TEG). Univariate and multivariate analyses were performed to select risk factors for RLN injury.

RESULTS

The RLN injury rate was higher in PTC (6.3%) than in benign cystic (1.2%, P = 0.019) and solid nodules (2.9%, P = 0.018). PTC subgroup analysis showed that the RLN injury rate was higher in T1b (10.7%) and T2 (28.6%) PTC than in T1a PTC (5.0%, P < 0.05). In the PTC group, TEG distance, anterior capsule distance, median capsule distance, posterior capsule distance, and maximum nodule diameter were risk factors for RLN injury. The logistic regression fitting of the nomogram showed high prediction efficiency (C-Index 0.876). The main cause of RLN injury was insufficient medial isolating fluid (MIF). The safety thicknesses of MIF for benign cystic, benign solid, and PTC nodules were 3.1 mm, 3.7 mm, and 3.9 mm, respectively.

CONCLUSION

Several risk factors for RLN injury should be considered before thermal ablation of thyroid nodules. The RLN injury rate could be predicted with the nomogram.

Safety and Efficacy of Ultrasound-Guided Radiofrequency Ablation for Benign Nonfunctional Thyroid Nodules in Children: A Retrospective Study of 62 Patients with Over Four Years of Follow-Up

Background: Image-guided radiofrequency ablation (RFA) for benign nonfunctional thyroid nodules in adults has been shown to be effective and safe, but few trials address the use of RFA in children. Therefore, this study was designed to assess the efficacy and safety of RFA application to benign nonfunctional thyroid nodules in children. Methods: A retrospective study of RFA for 70 benign nonfunctional thyroid nodules in 62 children with four-year follow-up was conducted. Volume reduction ratio (VRR), technique efficacy, regrowth rate, symptom score, and cosmetic score were calculated to evaluate the efficacy. Complications and side effects were recorded. Logistic regression analysis was performed to identify risk factors, and subgroup analyses were performed. Results: Patients were followed up for at least four years (59.1 ± 10.5 months, range 48-85 months). After RFA treatment, the VRR and technique efficacy rates were highest at the first year^* (77.5% and 91.4%, respectively) but decreased by four years (55.1% and 81.4%, respectively). The symptom score decreased from 4.0 ± 2.1^* to 0.8 ± 1.6 (Z = -6.82, p < 0.001), and the cosmetic score decreased from 3.3 ± 0.7 to 1.3 ± 0.9 (Z = -7.0, p < 0.001).^* The nodule regrowth rate was 22.9%, of which 56.3% of cases represented loss of efficacy. In the cases of loss of efficacy, 66.7% had greater volume than their initial presentation. Patients who received a second RFA treatment due to loss of efficacy lost efficacy again. Bilateral nodules, low vascularity, and low cystic components were independent risk factors correlating with technique efficacy. Bilateral nodules correlated with low VRR, low efficacy rate, and high regrowth rate. Nodules with a higher proportion of cystic components had higher VRR. The overall complication rate was 4.8%. Conclusions: RFA was effective in reducing the volume of benign nonfunctional thyroid nodules in children, providing significant symptomatic relief with a good safety profile during short- and long-term follow-up. RFA is a good minimally invasive treatment modality for selected pediatric patients, and it may not be appropriate for the treatment of bilateral thyroid nodules in children.

Efficacy and safety of radiofrequency ablation for calcified benign thyroid nodules: results of over 5 years' follow-up

Purpose

To evaluate the efficacy and safety of radiofrequency ablation (RFA) for treating calcified benign thyroid nodules (CBTNs).

Methods

Fifty-two patients with 52 CBTNs who underwent RFA in our hospital were included in this retrospective study. According to the size of calcifications, CBTNs were divided into two groups: the punctate echogenic foci (PEF) group and macrocalcification group. Moreover, the macrocalcification group was further subdivided into two groups, the strong group and the weak group, based on their morphologic characteristics. After the RFA procedure, routine ultrasound (US) and clinical evaluation were performed at 1, 3, 6 and 12 months postoperatively and every 12 months thereafter.

Results

The mean follow-up time was 68.98 ± 7.68 months (60–87 months), and the 5-year mean volume reduction rate (VRR) after RFA was 92.95%, with a complication rate of 0.6% (3/52). The mean initial volume of the macrocalcification group was significantly larger than that of the PEF group (9.94 ± 24.60 ml vs. 0.23 ± 0.22 ml, respectively; P = 0.011). Thus, their VRRs were not comparable between the two groups. However, baseline characteristics did not show statistically significant differences between the strong and weak macrocalcification subgroups. The VRRs of the strong subgroup were significantly lower than those of the weak subgroup at the 3-year, 4-year, and 5-year follow-ups.

Conclusion

RFA was effective and safe for treating CBTNs. Strong macrocalcification was related to the VRR of CBTNs after the RFA procedure.

Image-guided thermal ablation in autonomously functioning thyroid nodules. A retrospective multicenter three-year follow-up study from the Italian Minimally Invasive Treatment of the Thyroid (MITT) Group

OBJECTIVES

To report the results of a multicenter retrospective evaluation of the clinical outcomes of thermal ablation (TA) in a large series of autonomously functioning thyroid nodules (AFTN) with a follow-up protracted up to 3 years.

METHODS

Patients treated with single TA for an AFTN in Italy were included. Changes in nodule volume, TSH values, and ongoing anti-thyroid therapy were assessed at the 2-, 6-, 12-, 24-, and 36-month follow-up controls. Complications and need of any additional therapy after TA were also registered.

RESULTS

A total of 361 patients (244 females, 117 males, median age 58 years, IQR 46-70 years) were included. Nodule volume was significantly reduced at all time points (p < 0.001) (median volume reduction 58% at 6-month and 60% at 12-month). Serum TSH values increased significantly at all time points. After TA, anti-thyroid therapy was withdrawn in 32.5% of patients at 2 months, in 38.9% at 6 months, and in 41.3% at 12 months. A significant difference in the rate of patients who withdrawn medical therapy at 12 months was registered between small (< 10 mL) (74%), medium (49%), or large (> 30 mL) nodules (19%). A single major complication occurred (0.25%). Additional treatments were needed in 34/361 (9.4%) of cases including 4 (1.1%) surgical treatment.

CONCLUSIONS

Image-guided thermal ablation offers a further safe and effective therapeutic option in patients with AFTN. Clinical outcomes are significantly more favorable in small than in large size AFTN.

KEY POINTS

• Thermal ablations (TA) can be safely and effectively used in patients with autonomously functioning thyroid nodules (AFTN). • TA results in a clinically significant nodule volume reduction that is paralleled by TSH level normalization and anti-thyroid drug therapy discontinuation (after TA anti-thyroid therapy was withdrawn in 41.3% at 12 months). • Clinical outcomes after TA are more favorable in small nodules, and when a large amount of thyroid nodule tissue is ablated.

Efficacy and Safety of Radiofrequency Ablation for the Treatment of Autonomously Functioning Thyroid Nodules: A Long-Term Prospective Study

Objective

This study aims to evaluate the efficacy and safety of RFA in the AFTN treatment after 2 years of follow-up and to find the factors related to treatment responses through TSH level and VRR.

Materials and Methods

This long-term prospective study was conducted from September 2017 to April 2021 on 17 AFTNs treated with RFA. Clinical evaluations, thyroid function tests, thyroid scintigraphy, and ultrasonography examinations were performed at 1 month, 3 months, 6 months, and 24 months after ablation. The primary endpoint was the success rate of RFA in restoring the euthyroidism stage after 24 months of follow-ups; secondary outcomes were VRR and improvements of US parameters, clinical examinations, and complications. The Spearman rank correlation test was used to determine related factors with treatment response variables.

Results

At the 24 months after the procedure, symptom score, cosmetic score, vascularity grade, and nodule volume significantly decreased. The VRR reduced approximately 42.77%, 63.13%, 78.3%, and 95.65% after 1 month, 3 months, 6 months, and 24 months follow-up. All 17 patients were restored euthyroid state without taking ATDs. No major complications were collected. The last TSH level was significantly correlated with the age of patients (Spearman rho = −0.637, p = 0.008). The VRR was significantly correlated with age of patients (Spearman rho = 0.566, p = 0.018) and initial TSH (Spearman rho = 0.485, p = 0.048).

Conclusion

RFA was demonstrated as a safe and effective option for AFTN treatment in long-term follow-up. It can be used as an alternative treatment with encouraging results.

Efficacy of radiofrequency ablation for metastatic papillary thyroid cancer with and without initial biochemical complete status

OBJECTIVE

The application of radiofrequency ablation (RFA) for recurrent thyroid cancer has been demonstrated to effectively manage lesions at critical locations, such as abutting the trachea, with limited complications. Comprehensive investigation of both biochemical (B) and structural (S) change after RFA remains limited. We herein present the first single-center experience of RFA for the treatment of locoregional recurrent thyroid cancer in Taiwan.

DESIGN

23 patients were enrolled, and the treatment responses after RFA were divided into four groups (E, S(+), B(+), and SB(+)), and then compared. The RFA technique, follow-up strategy, changes in pre-and post-operative status, and complications are presented. The volume reduction rate at 1, 3, and 6 months, and the differing responses between lesions abutting/not abutting the trachea are also discussed.

RESULTS

In patients with pre-RFA structural and biochemical incomplete (SB(+)) status, presenting with lesion with an initial maximum diameter of >3.2cm, a higher rate of structural incomplete status at the 6-month follow-up was noted in ROC analysis, with a sensitivity of 57% and specificity of 91%. Favorable structural remission after RFA was noted, and 60.9% of patients achieved biochemical complete status. No significant correlation was noted between the trachea-abutted lesion number and complete remission (p= 0.474). No significant difference in RFA efficacy was noted between the lesions abutting/not abutting the trachea.

CONCLUSIONS

This retrospective study reveals that RFA can achieve both structural and biochemical improvements for locoregionally recurrent thyroid cancer, with a low complication rate. Nearly half of the patients achieved an excellent response after RFA, while a favorable treatment response can be achieved despite the lesion abutting the trachea, with a mean VRR of 84.74%.

Successful Applications of Food-Assisted and -Simulated Training Model of Thyroid Radiofrequency Ablation

BACKGROUND

Radiofrequency ablation (RFA) for benign thyroid nodules is one kind of scarless treatment for symptomatic or cosmetic benign thyroid nodules. However, how to train RFA-naive physicians to become qualified operators for thyroid RFA is an important issue. Our study aimed to introduce a successful training model of thyroid RFA.

MATERIALS AND METHODS

We used a food-assisted and -simulated training model of thyroid RFA. Chicken hearts were simulated into thyroid nodules, three-layer pork meats were simulated into peri-thyroid structure, and gel bottles were simulated into trachea, respectively. Successful training ablations were defined as chicken hearts that were fully cooked. After repeating training ablations of chicken hearts at least 100 times with the nearly 100% success rates for three young trainees, they served as the first assistant for the real procedures of thyroid RFA and then were qualified to perform thyroid RFA on real patients under the supervision of one experienced interventional radiologist.

RESULTS

23 real patients who received RFA and follow-up at least 6 months after treatment were included in Linkou Chang Gung Memorial Hospital from January 1, 2020 to October 1, 2021. Three young endocrinologists performed thyroid RFA independently. The outcomes were volume reduction rate (VRR), major complications and minor complications. The median VRR at 12 months was 82.00%, two major complications were transient hoarseness, and three minor complications were wound pain. All complications were completely recovered within three days.

CONCLUSIONS

For young and RFA-native physicians without any basic skills of echo-guided intervention, this food-assisted and -simulated training model of thyroid RFA was useful for medical training and education.

Contrast-enhanced ultrasound is a reliable and reproducible assessment of necrotic ablated volume after radiofrequency ablation for benign thyroid nodules: a retrospective study

PURPOSE

To investigate the intra- and inter-observer reliability and agreement of contrast-enhanced ultrasound (CEUS) in measuring ablated volume (Va) after radiofrequency ablation (RFA) for benign thyroid nodules.

MATERIALS

This retrospective study evaluated 65 patients with 74 benign thyroid nodules who underwent RFA. Patients were followed up at 1, 3, 6, and 12 months and every 12 months thereafter. Two independent observers measured the Va using CEUS during the same follow-up visit. The intra- and inter-observer reliability was assessed using intraclass correlation coefficient (ICC) with 95% confidence interval. The Bland-Altman analysis was used to evaluate the inter-observer agreement, which was expressed as a mean difference with 95% limit of agreement (LOA).

RESULTS

No significant difference was found in Va measurements by the two observers with a mean follow-up time of 41.17 ± 16.80 months (all p > 0.05). The intra- and inter-observer reliability were both excellent (ICC >0.90) at each follow-up period. The 95% LOA became wider over the follow-up period. The smallest 95% LOA was found at 1 month with a LOA from 0.8117 to 1.122, and the largest 95% LOA was from 0.5694 to 1.343 at 36 months.

CONCLUSIONS

CEUS could provide a reliable and reproducible assessment of Va after RFA for benign thyroid nodules. In clinical post-ablation follow-up, the irregular morphology of ablated area and the variation by different observers could not affect the assessment of Va by CEUS.

Radiofrequency ablation of recurrent thyroid cancers: anatomy-based management

Although differentiated thyroid cancer has an excellent prognosis and low mortality, its recurrence rate has been reported to be very high. While surgery is recommended as the standard treatment for recurrent thyroid cancer, reoperation may increase the incidence of complications due to fibrosis and anatomical distortion. In patients with high surgical risk or those who refuse repeated surgery, ultrasonography-guided ablation techniques including radiofrequency ablation, ethanol ablation, and laser ablation are suggested as alternative treatments. In this manuscript, we introduce an anatomy-based management concept for radiofrequency ablation for recurrent thyroid cancer, and present a review of the relevant literature, including indications, basic techniques, clinical outcomes, and complications.

A comprehensive review of interventional ablation techniques for the management of thyroid nodules and metastatic lymph nodes

Thyroidectomy remains the gold standard treatment for benign, symptomatic, or enlarging thyroid nodules, malignant nodules, and metastatic lymph node disease. However, in the past 2 decades, image-guided interventional techniques have emerged as promising alternative treatments for these conditions. Percutaneous ethanol ablation is now an accepted first-line treatment for recurring cystic thyroid nodules. Thermal ablation techniques such as high-intensity focused ultrasound, laser ablation, radiofrequency ablation, and microwave ablation have shown efficacy in producing a nodular volume reduction of greater than 50% that is maintained for several years with resolution of local compressive symptoms. There is also increasing evidence that these techniques can effectively treat papillary thyroid microcarcinomas and recurrent metastatic lymph node disease. Because these interventional ablation techniques are performed safely in an outpatient setting, are well tolerated, and the risk for needing thyroid hormone supplementation is negligible, they are becoming a popular alternative treatment to surgical resection. In this comprehensive review, we discuss each of these percutaneous interventions: the devices and techniques, the advantages and disadvantages of each energy, and summarize the outcomes published in the literature.

Learning curve analysis of radiofrequency ablation for benign thyroid nodules

BACKGROUND

Radiofrequency ablation (RFA) has been increasingly accepted as an alternative to surgery in the treatment of symptomatic benign thyroid nodules. However, the learning curve of thyroid RFA has yet to be defined. We hypothesized a temporal relationship between proficiency of the skill and midterm volume reduction.

METHODS

Consecutive patients who underwent RFA and had at least a six-month follow-up were identified from an institutional database. The cumulative sum (CUSUM) analysis was applied to visualize the learning curve on the adjusted volume reduction rate (VRR).

RESULTS

A total of 102 nodules in 93 patients were included in the analysis. Linear regression revealed that nodule composition was the main predictor of the VRR. The composition-adjusted VRR increased with the chronological treatment order. The series was divided into three phases based on inflection points of the CUSUM analysis: the initial learning phase (case 1-20), consolidation phase (case 21-65), and proficiency phase (case 66-102). In the later phase, more solid nodules were treated, power output used by the operator was higher, and RFA treatment time was longer.

CONCLUSION

The treatment efficiency of thyroid RFA was associated with technical proficiency, suggesting the presence of a learning curve effect.

Ultrasound-Guided Radiofrequency Ablation Versus Thyroid Lobectomy for Low-Risk Papillary Thyroid Microcarcinoma: A Propensity-Matched Cohort Study of 884 Patients

Background: Thermal ablation (TA) has been applied in patients with low-risk papillary thyroid microcarcinoma (PTMC) who refuse surgery or active surveillance (AS). Recently, TA has been proposed as a potential therapeutic option for patients who are suitable for surgery or AS. However, the clinical outcomes of TA versus surgery remains controversial because of a lack of sufficient data. This study aimed to compare the clinical outcomes between radiofrequency ablation (RFA) versus thyroid lobectomy (TL) for low-risk PTMC in a large cohort. Methods: This retrospective study evaluated 884 patients with unifocal low-risk PTMC treated with TL or RFA from June 2014 to March 2018. Among them, 460 patients underwent TL (TL group) and 424 patients, who refused surgery or AS, underwent RFA (RFA group). Patients were regularly followed up after treatment. Local tumor progression, recurrence-free survival (RFS), complications, and treatment variables, including procedure time, estimated blood loss, hospitalization, and cost, were compared after propensity score matching (PSM). Results: After PSM, a total of 332 patients underwent TL (mean ages 43.8 ± 9.5 years) and 332 underwent RFA (mean ages 44.1 ± 9.5 years). During the follow-up (median [interquartile ranges], 48.3 [23.2] months), no significant differences were observed in local tumor progression (1.8% vs. 3.3%, p = 0.209), lymph node metastasis (0.6% vs. 0.6%, p = 1.000), recurrent PTMC (1.2% vs. 2.4%, p = 0.244), persistent lesion (0% vs. 0.3%, p = 0.317), and 4-year RFS rates (98.2% vs. 97.0%, p = 0.223) between the TL and RFA groups. Distant metastasis was not detected. None of the patients who were treated by RFA underwent delayed surgery. Patients undergoing RFA had shorter procedure time (3.4 [2.5] vs. 86.0 [37.0] minutes, p < 0.001), lower estimated blood loss (0 vs. 20 [10.0] mL, p < 0.001), shorter hospitalization (0 vs. 7.0 [3.0] days, p < 0.001), lower cost ($2035.7 [254.0] vs. $2269.1 [943.4], p < 0.001) and lower complication rate (0% vs. 4.5%, p < 0.001) than those treated by TL. The association between treatment modality and recurrence remained nonsignificant after Cox analysis (p = 0.247). Conclusions: This large matched study revealed comparable four-year clinical outcomes between RFA and TL for low-risk PTMC. As a minimally invasive modality, RFA may be a promising alternative to the existing treatment options for low-risk PTMC.

Computer-Analyzed Ultrasound Predictors of the Treatment Efficacy of Radiofrequency Ablation for Benign Thyroid Nodules

AIM

Radiofrequency ablation (RFA) is a relatively safe and efficient alternative to surgery for patients with benign thyroid nodules. We investigated predictive factors associated with volume reduction using digital imaging analysis.

METHODS

In this retrospective study, a prospectively maintained database containing the data of patients who received treatment from April 2019 to March 2020 was analyzed. Computerized analysis for quantitative measurement of echogenicity, heterogeneity, and the proportion of cystic components was performed on ultrasonographic images. The volume reduction rate (VRR) was calculated during follow-up. Treatment efficacy was defined as a volume reduction greater than 50% of baseline volume.

RESULTS

The median volume of 58 benign thyroid nodules before RFA was 22.7 mL. Of 53 nodules with sufficient follow-up, the median VRR was 46.4%, 61.5%, 63.4%, and 67.4% at 1, 3, 6, and 12 months, respectively. Overall, at one-year follow-up, treatment efficacy was achieved in 39 (74%) nodules. In a multivariate regression analysis, the proportion of cystic components and RFA treatment time were independently associated with treatment efficacy. A subgroup analysis focusing on solid nodules indicated a negative correlation between echogenicity and VRR.

CONCLUSIONS

The proportion of cystic components in thyroid nodules is the main predictor of RFA treatment efficacy. In solid nodules, higher echogenicity is associated with a lower volume reduction.

Safety and Efficacy of Radiofrequency Ablation of Thyroid Nodules-Expanding Treatment Options in the United States

CONTEXT

Radiofrequency ablation (RFA) has only recently gained popularity in the United States for treatment of thyroid nodules (TNs), with a limited number of patients having undergone the procedure in this country.

OBJECTIVE

To evaluate the safety and efficacy of RFA of TNs performed in an outpatient setting in the United States.

METHODS

This is a retrospective, single-center study of 53 patients who underwent RFA of 58 TNs between November 2018 and January 2021. The reduction in volume of nodule, cosmetic and symptomatic improvement, effect on thyroid function, and complications following RFA were assessed.

RESULTS

Eleven out of 53 patients were excluded from the analysis. A total of 47 benign TNs (23 nonfunctioning thyroid nodules [NFTNs] and 24 autonomously functioning thyroid nodules [AFTNs]), were assessed after RFA. The median reduction in volume was 70.8% after a median follow-up period of 109 days, with symptomatic and cosmetic improvement (P < 0.0001). Compared with larger nodules, smaller nodules had greater volume reduction (P = 0.0266). RFA improved thyrotropin (TSH) in AFTNs (P value = 0.0015) and did not affect TSH in NFTNs (P value = 0.23). There were no major complications; however, 1 patient had self-limited local bleeding and another had transient voice change that recovered in 6 months.

CONCLUSION

RFA is a safe and efficacious treatment for symptomatic NFTNs and AFTNs in our population and is especially effective for smaller nodules. RFA should be considered an alternative for TNs in patients who cannot or do not want to undergo surgery.

Analyzing the adoption of radiofrequency ablation of thyroid nodules using the diffusion of innovations theory: understanding where we are in the United States?

Thyroid nodules are very common and found in up to 68% of the general U.S. population on ultrasound. Although thyroidectomy has long been the mainstay of treatment for malignant and symptomatic benign thyroid nodules, various interventional ablative techniques have emerged in the last couple of decades as alternative non-surgical treatment options. Globally, the most widely adopted technique has been ultrasound-guided radiofrequency ablation (RFA). RFA of thyroid nodules was first performed in 2002, and there has been an expanding body of evidence since 2006 showing that RFA and other interventional ablative techniques are effective treatments for benign solid thyroid nodules, toxic adenomas, and thyroid cysts. More recently, evidence has emerged that these techniques may be effective treatment for low-risk thyroid cancer and recurrent disease. Despite these findings, the United States has been slow to adopt these techniques, with only a single publication on RFA more than a decade after the first series was published. EM Rogers’ Diffusion of Innovation Theory provides us the appropriate lens to carefully analyze the process of adoption of RFA for thyroid nodules-to understand where we are currently, as well as, the important next steps that must be accomplished in order for RFA and other ablative techniques to be successfully adopted into the management algorithm of thyroid nodules in the United States.

Efficacy and safety of radiofrequency ablation for benign thyroid nodules in patients with previous thyroid lobectomy

Background

Radiofrequency ablation (RFA) is recommended for the treatment of benign thyroid nodules. However, data on the clinical role of RFA for benign thyroid nodules in patients with history of thyroid lobectomy are insufficient. The purpose of this study was to evaluate the efficacy and safety of radiofrequency ablation (RFA) for benign thyroid nodules in patients who had previously undergoing thyroid lobectomy.

Methods

From May 2015 to October 2018, a total of 20 patients (19 females, 1 male, mean age 49.50 ± 14.26 years, range 22–74 years) with 20 benign thyroid nodules (mean volume 15.04 ± 21.17 ml, range 0.40–69.67 ml) who had undergone previous thyroid lobectomy were included in this retrospective study. Patients were followed up at 3, 6, 12 months after RFA and every 12 months thereafter by ultrasound, clinical evaluation and thyroid function. Volume, volume reduction rate (VRR), symptom score and cosmetic score were evaluated.

Results

During the mean follow-up time of 21.24 ± 16.41 months, the mean nodule volume decreased significantly from 15.04 ± 21.17 ml to 1.29 ± 1.17 ml (P = 0.018) with a mean VRR of 85.41 ± 12.17%. Therapeutic success was achieved in a single session for all thyroid nodules. The symptom score (P = 0.001) and cosmetic score (P = 0.001) were both significantly reduced at the last follow-up. The levels of free triiodothyronine (fT3), free thyroxine (fT4) and thyroid stimulating hormone were not significantly different at the last follow-up from those prior to treatment (all P > 0.05). No life-threatening complications or sequelae occurred after RFA.

Conclusions

As a minimally invasive modality, RFA was a safe, effective, and thyroid function-preserving option for patients with symptomatic benign thyroid nodules after a previous lobectomy.

Comparative efficacy of different ultrasound-guided ablation for the treatment of benign thyroid nodules: Systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Percutaneous ablation is currently deemed an additionally treatment option for benign thyroid nodules in the world, but possibly different effect among the ablation modalities is not clear. So we aim to evaluate the efficacy and complications of thermal/chemical ablation by network meta-analysis.

MATERIALS AND METHODS

In the network meta-analysis, PubMed, EMBASE and the Cochrane Library databases were searched from 1980 to 2020. Studies of adults with thyroid benign nodules under percutaneous ablation therapy were included. Percentage mean volume change, symptom score change, cosmetic score change and complications were evaluated by network meta-analysis.

RESULTS

In the network meta-analysis, Radiofrequency Ablation(RFA) with 2 treatment sessions group was associated with the highest reduction for the mean volume change during 6-month follow-up (MD = 79.09 and 95% CrI:48.23-89.94). There is no significant difference in the incidence of complications. Subgroup analysis showed that 2 sessions of Radiofrequency Ablation (RFA) ranks the highest probability (surface under the cumulative ranking curve (SUCRA) values 77.9) of being the most efficacious treatment for solid or predominantly solid benign nodules. Ethanol ablation (EA) ranked first (SUCRA value 81.1) in the treatment for cyst or predominantly cyst benign nodules.

CONCLUSION

RFA appears to be superior to other US-guided percutaneous ablation in reducing benign thyroid nodule volume during short- and long-term follow-up. In the subgroup analysis, RFA with 2 treatment sessions showed the most significant effectiveness for solid benign thyroid nodules and EA showed more effectiveness to decrease the volume of cyst benign thyroid nodules.

Efficacy and Safety of Single-Session Radiofrequency Ablation in Treating Benign Thyroid Nodules: A Short-Term Prospective Cohort Study

OBJECTIVE

The aims of this study are to evaluate the safety and efficacy of RFA in the treatment of benign thyroid nodule(s) and to find independent factors related to the volume reduction rate of the nodule(s).

MATERIALS AND METHODS

This short-term prospective study from a single medical center was conducted on 93 benign thyroid nodules in 93 patients treated with RFA. Two basic techniques were used: the trans-isthmic approach and moving-shot technique. Clinical and ultrasonography examinations were performed at 1- and 3-month follow-up after the treatment session. Primary outcomes included volume reduction ratio (VRR) at 1-month and 3-month follow-ups; secondary outcomes were therapeutic success rate and complications. Multiple linear regression analysis was used to determine independent factors associated with VRR.

RESULTS

A final sample of 78 patients with 78 nodules, given participant rate 83.8% (including 60 solid nodules, 16 predominantly cystic nodules, and 2 thyroid cysts), was followed up for 3 months. The mean volume reduction ratio was 41.47% and 64.72% after 1-month and 3-month follow-ups, respectively. The therapeutic success rate was 30.8% at 1-month and 84.6% at 3-month follow-ups. Symptom score and cosmetic score improved significantly. There was no change in thyroid function tests. Two minor complications (transient voice change) were found. The multiple linear regression analysis showed that the internal component of the nodules significantly related to the VRR during the 3-month follow-up (β = 23.00; 95%CI (7.59-38.45)).

CONCLUSION

RFA was demonstrated as a safe and effective option for benign thyroid nodules treatment. It can be used as an alternative treatment with encouraging results.

Review of clinical tumor ablation advance in Asia

Tumor ablation has been widely applied in Asia, accounting for 44.65% of clinical studies worldwide. We reviewed 5853 clinical studies to provide insight on the advance of tumor ablation in Asia chronologically and geographically among different techniques and organs. Since 1998, tumor ablation application has dramatically evolved in Asia. All kinds of ablation techniques, including percutaneous ethanol injection (PEI), radiofrequency ablation (RFA), microwave ablation (MWA), laser ablation (LA), cryoablation (CA), high-intensity focused ultrasound (HIFU), and irreversible electroporation (IRE), have been applied, with the first application of PEI and the most popular application of RFA. Twenty-five countries and one district in Asia have applied tumor ablation in various organs, including liver, lung, uterus, thyroid, kidney, pancreas, bone, prostate, breast, adrenal gland, lymph node parathyroid, esophagus, etc. Due to the high incidence of tumors as well as advanced economy and technology, East Asia accounted for 93.87% of studies, led by China (45.00%), Japan (32.72%), South Korea (12.10%), and Taiwan (4.03%). With the enrichment of evidence from large-scale multicenter and randomized control studies, China and South Korea have issued several guidelines on tumor ablation for liver, lung, and thyroid, which provided recommendations for global standardization of tumor ablation techniques. Therefore, Asia has made active contribution to global tumor ablation therapy.KeypointsKey point 1: Asia accounted for 44.65% of clinical studies worldwide on tumor ablation.Key point 2: Twenty-five countries and one district in Asia have used tumor ablation in various organs, and East Asia accounted for 93.87% of studies, led by China (45.00%), Japan (32.72%), South Korea (12.10%), and Taiwan (4.03%).Key point 3: China and South Korea have issued several guidelines on tumor ablation for liver, lung, and thyroid, which provided recommendations for global standardization of tumor ablation techniques.

Long-Term Outcomes of Thermal Ablation for Benign Thyroid Nodules: The Issue of Regrowth

Thermal ablation (TA) for benign thyroid nodules (BTNs) is widely accepted as an effective and safe alternative to surgery. However, studies on the long-term outcomes of TA have reported problems with nodule regrowth and symptom recurrence, which have raised the need for adequate control of regrowth. Therefore, a more complete TA with a longer-lasting treatment effect may be required. In this study, we review and discuss long-term outcomes and regrowth of BTNs following TA and evaluate factors affecting the long-term outcomes. We also discuss the management of regrowth based on long-term outcomes.