Nodule size as predictive factor of efficacy of radiofrequency ablation in treating autonomously functioning thyroid nodules

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.

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.

Cost Effectiveness of Definitive Treatment Strategies for Autonomously Functioning Thyroid Nodules

OBJECTIVE

Autonomously functioning thyroid nodules (AFTN) can be treated with antithyroid drugs, radioactive iodine (RAI), thyroid lobectomy or radiofrequency ablation (RFA). Although surgery is most definitive, some patients require lifelong hormone supplementation. RFA avoids this sequela, but its efficacy depends on nodule size. This study aims to compare the relative cost-effectiveness of RAI, RFA and lobectomy for treatment of AFTNs.

STUDY DESIGN

A Markov analysis model was created to simulate clinical outcomes, costs and utilities for three AFTN treatments: (1) thyroid lobectomy, (2) RAI, and (3) RFA.

PATIENTS

This mathematical model was created using published literature and modeling.

MEASUREMENTS

Transition probabilities, utilities and costs were extracted from published literature, Medicare, and RedBook. The willingness to pay threshold was set to $100,000 per quality-adjusted life year. The model simulated 2-year outcomes, reflecting RFA literature. Sensitivity analyses were conducted to account for uncertainty in model variables.

RESULTS

In the base model, RAI dominated both lobectomy and RFA, with lower estimated cost ($2000 vs. $9452 and $10,087) and higher cumulative utility (1.89 vs. 1.82 and 1.78 quality-adjusted life years). One-way sensitivity analyses demonstrated that relative cost-effectiveness between surgery and RFA was driven by the probability of euthyroidism after RFA and hypothyroidism after lobectomy. RFA becomes more cost-effective than surgery if the rate of euthyroidism after ablation is higher than 69% (baseline 54%).

CONCLUSION

Based on published data, RAI is most cost-effective in treating most AFTN. Surgery is more cost-effective than RFA in most scenarios, but RFA may be more resource-efficient for smaller nodules with a high likelihood of complete treatment.

The Role of Radiofrequency Ablation in Benign and Malignant Thyroid Nodules

Radiofrequency ablation (RFA) offers a minimally invasive solution for benign, autonomously functioning (AFTN), and malignant thyroid nodules. The technique utilizes high-frequency alternating current to induce coagulative necrosis, effectively destroying target tissue. RFA is performed in the outpatient setting with local anesthesia and sonographic guidance. RFA is effective in producing substantial volume reduction rates in benign nodules and is emerging as a favorable option in AFTN and papillary thyroid microcarcinoma. RFA's advantages include lower complication rates, minimal scarring, and improved quality-of-life outcomes compared to surgery. However, its efficacy in larger and recurrent malignancies requires further investigation.

A novel guided approach to radiofrequency ablation of thyroid nodules: the Toronto Sunnybrook experience

Introduction

Thyroid nodules are extremely common being detected by ultrasonography in up to 67% of the population, with current surgical tenet maintaining that lobectomy is required for large symptomatic benign nodules or autonomously functionally nodules resulting in a risk of hypothyroidism or recurrent laryngeal nerve injury even in high volume centres. The introduction of radiofrequency ablation (RFA) has allowed thermal ablation of both benign and autonomously functioning thyroid nodules with minimal morbidity. The moving shot technique is the most well-established technique in performing RFA of thyroid nodules, and has proven to be safe, efficacious, accurate and successful amongst experienced clinicians. The purpose of this article to propose the use of a novel guide when performing RFA of thyroid nodules in clinical practice utilizing the moving shot technique.

Methods

The technique proposed of RFA involves the use of a 10MHz linear ultrasound probe attached to an 18G guide which provides robust in line visualisation of a 7cm or 10cm radiofrequency probe tip (STARmed, Seoul, Korea) utilizing the trans isthmic moving shot technique. A geometric analysis of the guide has been illustrated diagrammatically.

Results

The use of an 18G radiofrequency probe guide (CIVCO Infiniti Plus™ Needle Guide) maintains in line visualisation of the radiofrequency probe over a cross-sectional area up to 28cm2, facilitating efficient and complete ablation of conceptual subunits during RFA of thyroid nodules.

Discussion

Radiofrequency ablation of thyroid nodules can be performed safely and effectively using the novel radiofrequency probe guide proposed which we believe potentially improves both accuracy and overall efficiency, along with operator confidence in maintaining visualisation of the probe tip, and hence we believe provides a valuable addition to the armamentarium of clinicians wishing to embark on performing RFA of thyroid nodules.

Radioiodine versus radiofrequency ablation to treat autonomously functioning thyroid nodules: a systematic review and comparative meta-analysis

PURPOSE

Radioiodine (RAI) is a well-established first-line therapy for autonomously functioning thyroid nodules (AFTN). Radiofrequency ablation (RFA) is a minimally invasive procedure that has been proposed as an alternative treatment option for hyperthyroidism caused by AFTN. Although RFA has been shown to be useful for reducing nodule volume and improving TSH levels in AFTN, no comprehensive comparative clinical studies have been proposed to evaluate the overall response to RFA treatment. The aim of this comparative systematic review and meta-analysis was to evaluate the response of RAI and RFA treatments in AFTN.

METHODS

A systematic search strategy was applied in PubMed, Web of Science, Scopus, Cochrane Library, and ClinicalTrials.gov until July 2023 without time or language restrictions. Studies investigating the response to RAI and/or RFA treatment in AFTN patients 6 and/or 12 months after treatment were included. The risk of bias was assessed based on the study design. Random-effect models were used for the meta-analysis.

RESULTS

Twenty-three articles (28 reports) met the inclusion criteria and were included in the study. Overall, RAI therapy was found to have a significantly higher treatment response (94%) than RFA (59%), although the volume of AFTNs was reduced to a similar extent. In the direct comparison (n = 3 studies), RFA showed a higher risk of non-response than RAI (RR, 1.24; 95% CI, 0.94-1.63; z = 1.55; p = 0.12).

CONCLUSIONS

Our results demonstrate the superiority of RAI over RFA in terms of success rates and safety profile and confirm RAI as the first choice for the treatment of AFTNs.

Radiofrequency Ablation for Benign Nodules and for Cancer, Too?

Radiofrequency ablation (RFA) is a minimally invasive procedure performed under ultrasound guidance that offers the ability to significantly reduce the size of benign thyroid nodules. Although application for benign nodules has only emerged during the past 5 to 10 years in North America, RFA has an impressive track record of nodule reduction, compressive and cosmetic symptom improvement, and excellent safety profile without the morbidity of open surgery. The role of RFA in autonomous functioning nodules, thyroid cancer, and indeterminate nodules is controversial and remains an area of investigation.

Five-year follow-up results of thermal ablation for benign thyroid nodules: Systematic review and meta-analysis

OBJECTIVES

Confidence in long-term treatment results of thermal ablation for benign thyroid nodules (BTNs) is required in comparison with surgery. The objective of this meta-analysis is to report 5-year follow-up results of thermal ablation for BTNs.

METHODS

Ovid PUBMED, COCHRANE, and EMBASE databases were searched through Feb 30, 2023, for studies reporting outcomes in patients with BTNs treated with thermal ablation and followed up for about 5 years. Pooled volume reduction rates (VRRs) at 6, 12, 24, 36, 48, and 60 months after thermal ablation were assessed. Data were extracted and methodological quality was assessed independently by two radiologists according to the PRISMA guidelines.

RESULTS

Five studies, involving 939 patients, met the inclusion criteria through database searches. 137 patients experienced local nodules recurrence during a mean pooled 59.25-month follow-up. Seventeen of them proved to be non-benign. Fifty of all patients with nodules regrowth had a secondary surgery, while 35 had a secondary thermal ablation. The pooled mean major complication rate was 7.70 %, with no patient experiencing life-threatening or delayed complications.

CONCLUSIONS

Thermal ablation is an excellent local nodules control method in patients with BTNs, and results in a clinically significant and long-lasting volume reduction of BTNs. The risk of regrowth and needing retreatment was lower after thermal ablation.

Radiofrequency Ablation for Benign Thyroid Nodules

CONTEXT

Thermal ablative techniques of the thyroid have recently gained clinical traction as a therapeutic alternative that provides symptomatic relief and confers potential advantages over surgery. A truly multidisciplinary technique, thyroid ablation is currently performed by endocrinologists, interventional radiologists, otolaryngologists, and endocrine surgeons. Radiofrequency ablation (RFA), specifically, has seen widespread adoption, particularly in the treatment of benign thyroid nodules. This review summarizes current evidence on the application of RFA in benign thyroid nodules, and provides a start to finish overview of procedural preparation, performance, and outcomes.

EVIDENCE ACQUISITION

A narrative review of literature focusing on RFA in the treatment of benign nodular disease was performed. Emphasis was placed on consensus statements, best practice guidelines, multi-institutional studies, and systematic reviews to summarize key concepts in candidacy, techniques, expectations, and outcomes.

FINDINGS

RFA is increasingly recognized as a first-line treatment strategy in the management of symptomatic nonfunctional benign thyroid nodules. It can also be considered in functional thyroid nodules with small volumes or in patients ineligible for surgery. A targeted and efficacious technique, RFA results in gradual volume reduction that preserves the function of the surrounding thyroid parenchyma. Proper procedural technique, proficiency in ultrasound, and experience in ultrasound-guided procedures are instrumental to maintaining low complication rates and achieving successful ablation outcomes.

CONCLUSIONS

In pursuit of a personalized approach, physicians across disciplines are increasingly incorporating RFA into their treatment algorithms, most commonly for benign nodules. As with any intervention, thoughtful selection and implementation ensure a safe procedure with optimal patient benefit.

Image-guided Thermal Ablation as a Promising Approach to Both Nontoxic and Toxic Autonomously Functioning Thyroid Nodules

RATIONALE AND OBJECTIVES

Although thermal ablation has been recommended as an alternative therapy option for autonomously functioning thyroid nodules (AFTN), current clinical evidence mainly focuses on toxic AFTN. This study aims to evaluate and compare the efficacy and safety of thermal ablation (percutaneous radiofrequency ablation or microwave ablation) in treating nontoxic and toxic AFTN.

MATERIALS AND METHODS

AFTN patients who received a single session of thermal ablation with a follow-up period ≥12 months were recruited. Changes in nodule volume and thyroid function, and complications were evaluated. Technical efficacy was defined as the maintenance or restoration of euthyroidism with a volume reduction rate (VRR) ≥80% at the last follow-up.

RESULTS

In total, 51 AFTN patients (age: 43.8±13.9 years, female: 88.2%) with a median follow-up period of 18.0 (12.0-24.0) months were included, where 31 were nontoxic (nontoxic group), and 20 were toxic (toxic group) before ablation. The median VRR was 96.3% (80.1%-98.5%) and 88.3% (78.3%-96.2%) in the nontoxic and toxic groups, respectively, and the respective euthyroidism rates were 93.5% (29/31, 2 evolved to toxic) and 75.0% (15/20, 5 remained toxic). The corresponding technical efficacy was 77.4% (24/31) and 55.0% (11/20, p=0.126). Except for one case of stress-induced cardiomyopathy in the toxic group, no permanent hypothyroidism or other major complications occurred in both groups.

CONCLUSION

Image-guided thermal ablation is efficacious and safe in treating AFTN, both nontoxic and toxic. Recognition of nontoxic AFTN would be helpful for treatment, efficacy evaluation, and follow-up.

General Principles for the Safe Performance, Training, and Adoption of Ablation Techniques for Benign Thyroid Nodules: An American Thyroid Association Statement

Background: The primary goal of this interdisciplinary consensus statement is to provide a framework for the safe adoption and implementation of ablation technologies for benign thyroid nodules. Summary: This consensus statement is organized around three key themes: (1) safety of ablation techniques and their implementation, (2) optimal skillset criteria for proceduralists performing ablative procedures, and (3) defining expectations of success for this treatment option given its unique risks and benefits. Ablation safety considerations in pre-procedural, peri-procedural, and post-procedural settings are discussed, including clinical factors related to patient selection and counseling, anesthetic and technical considerations to optimize patient safety, peri-procedural risk mitigation strategies, post-procedural complication management, and safe follow-up practices. Prior training, knowledge, and steps that should be considered by any physician who desires to incorporate thyroid nodule ablation into their practice are defined and discussed. Examples of successful clinical practice implementation models of this emerging technology are provided. Conclusions: Thyroid ablative procedures provide valid alternative treatment strategies to conventional surgical management for a subset of patients with symptomatic benign thyroid nodules. Careful patient and nodule selection are critical to the success of these procedures as is extensive pre-procedural patient counseling. Although these emerging technologies hold great promise, they are not without risk and require the development of a unique skillset and environment for optimal, safe performance and consistent outcomes.

Radiofrequency ablation for autonomously functioning nodules as treatment for hyperthyroidism: subgroup analysis of toxic adenoma and multinodular goitre and predictors for treatment success

PURPOSE

Treatment of hyperthyroidism caused by autonomously functioning thyroid nodules (AFTN) with 131I often leads to undesirable hypothyroidism. Radiofrequency ablation (RFA) has emerged as a promising alternative. This retrospective analysis aimed to examine the efficacy of, and postprocedural hypothyroidism after, RFA for AFTN.

METHODS

Patients with hyperthyroidism caused by AFTN and treated with RFA were included if follow-up of at least 1 year was available. Cure was defined as thyroid medication-free biochemical euthyroidism. To predict cure, patient and treatment factors were analysed. A distinction was made between solitary toxic adenoma (STA) and toxic multinodular goitre (TMG).

RESULTS

Forty-eight patients (36 STA, 12 TMG) were included. One year post-RFA cure rate was 72% in STA versus 25% in TMG (p = 0.004). One patient developed hypothyroidism. In 11 patients that remained hyperthyroid, a second RFA was successful in 83% of STA and 40% of TMG patients. At last available follow-up, this amounted to a total cure rate of 81% in STA and 33% in TMG (p = 0.002). In STA, cured patients had a higher baseline TSH and a lower FT3 than non-cured patients (p = 0.026 and 0.031). Cure was observed in 91% of patients when > 2.1 kJ/mL was delivered during RFA, compared to 44% when less energy was administered.

CONCLUSION

The efficacy of RFA was nearly 3 times higher in STA patients compared to TMG. Severity of hyperthyroidism and kJ/mL delivered during RFA predicts cure. Direct comparison to the current standard of care is needed to implement RFA in treatment of hyperthyroidism caused by AFTN.

Choice in Ablative Therapies for Thyroid Nodules

Ultrasound-guided ablation procedures have been growing in popularity and offer many advantages compared with traditional surgery for thyroid nodules. Many technologies are available, with thermal ablative techniques being the most popular currently though other nonthermal techniques, such as cryoablation and electroporation, are gaining interest. The objective of the present review is to provide an overview of each of the currently available ablative therapies and their applications in various clinical indications.

Approach to the Patient With a Suppressed TSH

Subclinical hyperthyroidism (SCH) is a laboratory diagnosis defined by a serum thyrotropin (TSH) concentration below the reference range (< 0.4 mU/L in most assays), and a free thyroxine (FT4) and 3,5,3'-triiodothyronine levels (FT3) in the reference range. Many patients diagnosed with SCH will be clinically euthyroid while others may present with manifestations characteristic of thyroid hormone excess, such as tachycardia, tremor, intolerance to heat, bone density loss, or weight loss. In addition to the laboratory abnormalities, patient factors such as age, symptoms, and underlying heart and bone disease are used to stratify patients for the risk of adverse outcomes and determine the appropriate treatment. Evaluation should include repeat thyroid function tests to document persistent TSH suppression, investigation of the underlying cause, as well as evaluation of the patient's risk of adverse outcomes in the setting of a subnormal TSH. Persistent SCH has been associated with an increased risk of a range of adverse events, including cardiovascular events such as atrial fibrillation and heart failure, bone loss and fracture, and in some studies, cognitive decline. Despite the consistent association of these adverse events with SCH, prospective studies showing improved outcomes with treatment remain limited. Management options include observation without active therapy, radioactive iodine ablation of the thyroid, antithyroid medication, thyroid surgery, or radiofrequency ablation, as appropriate for the patient and clinical setting. The choice of therapy should be guided by the underlying etiology of disease, patient factors, and the risks and benefits of each treatment option.

Association of BRAFV600E Mutation with the Aggressive Behavior of Papillary Thyroid Microcarcinoma: A Meta-Analysis of 33 Studies

An association between the BRAF^V600E mutation and the clinicopathological progression of papillary thyroid microcarcinoma (PTMC) has been suggested. We aimed to summarize the relevant literature and determine the predictive value of BRAF^V600E mutation in predicting clinical outcomes and risk stratification in patients with PTMC. A systematic search using PubMed, Cochrane, and Embase up to February 2020 was performed. A total of 33 studies met the inclusion criteria, resulting in a pool of 8838 patients, of whom 5043 (57.1%) patients were positive for BRAF^V600E mutation. Tumors with positive BRAF^V600E mutation had a higher tendency for multifocality (RR = 1.09, 95%CI = 1.03-1.16), extrathyroidal extension (RR = 1.79, 95%CI = 1.37-2.32), and lymph node metastasis (RR = 1.43, 95%CI = 1.19-1.71). Patients with BRAF^V600E mutation were at increased risk of disease recurrence (RR = 1.90, 95%CI = 1.43-2.53). PTMC in patients positive for the BRAF^V600E mutation is more aggressive than wild-type BRAF PTMC. Since BRAF-mutated PTMC is generally more resistant to radioiodine treatment, patients with BRAF^V600E-mutated PTMC may require earlier management, such as a minimally invasive ablative intervention. Conservative management by active surveillance may be suitable for patients with wild-type BRAF^V600E PTMC.

The influence of nodule size on clinical efficacy of ethanol ablation and microwave ablation on cystic or predominantly cystic thyroid nodules

Objective

To compare the efficacy and safety of ethanol ablation (EA) and microwave ablation (MWA) in the treatment of cystic or predominantly cystic thyroid nodules.

Methods

Patients with cystic or predominantly cystic thyroid nodules intervened with EA or MWA were retrospectively enrolled and divided into EA group (n = 30) and MWA group (n = 31). The volume and volume reduction rate (VRR) of thyroid nodules before ablation, and at 3 and 12 months after ablation were compared between the two groups. The effective rate (ER) and incidence of adverse events in both groups were recorded.

Results

The median VRR and ER at 3 months after ablation were significantly higher in EA group than in MWA group (81.30% vs 75.76%, P = 0.011; 76.67% (23/30) vs 51.61% (16/31), P = 0.040), while no significant difference was detected at 12 months (93.39% vs 88.78%, P = 0.141; 86.67% (26/30) vs 87.10% (27/31), P = 0.960). The median VRR of small nodules in EA group was significantly higher than that in MWA group (81.30% vs 71.18%, P = 0.006; 93.40% vs 83.14%, P = 0.032). There was no significant difference of median VRR in medium nodules at final follow-up between MWA and EA group (93.01% vs 89.68%, P = 0.482). Serious adverse events were not reported in both groups.

Conclusion

EA and MWA are both effective and safe in the treatment of cystic or predominantly cystic thyroid nodules. EA is more cost-effective and effective than MWA for small nodules, but it requires more cycles of treatment and may pose a higher risk of postoperative pain compared with MWA.

Minimally Invasive Techniques for the Management of Thyroid Nodules

Image-guided interventional techniques have emerged as promising treatments for thyroid disease. Percutaneous ethanol ablation, radiofrequency ablation, laser ablation, high intensity focused ultrasound, and microwave ablation have shown efficacy in treating benign thyroid disease. There is increasing evidence that these techniques may effectively treat papillary thyroid microcarcinomas, recurrent and metastatic disease, follicular neoplasms, and parathyroid lesions. They are performed in an outpatient setting, well-tolerated, with negligible risk for thyroid hormone supplementation, making them a popular alternative to surgical resection. In this comprehensive review, we discuss the devices, techniques, advantages, and disadvantages of each intervention, and summarize the published outcomes.

Nonsurgical Management of Thyroid Nodules: The Role of Ablative Therapies

CONTEXT

After a thorough evaluation most thyroid nodules are deemed of no clinical consequence and can be observed. However, when they are compressive, toxic, or involved by papillary thyroid carcinoma surgery or radioactive iodine (RAI) (if toxic) are the treatments of choice. Both interventions can lead to hypothyroidism and other adverse outcomes (eg, scar, dysphonia, logistical limitation with RAI). Active surveillance might be used for papillary thyroid microcarcinoma (PTMC) initially, but anxiety leads many cases to surgery later. Several ablative therapies have thus evolved over the last few years aimed at treating these nodules while avoiding described risks.

CASES

We present 4 cases of thyroid lesions causing concern (compressive symptoms, thyrotoxicosis, anxiety with active surveillance of PTMC). The common denominator is patients' attempt to preserve thyroid function, bringing into focus percutaneous ethanol injection (PEI) and thermal ablation techniques (radiofrequency ablation [RFA] being the most common). We discuss the evidence supporting these approaches and compare them with standard therapy, where evidence exists. We discuss additional considerations for the utilization of these therapies, their side-effects, and conclude with a simplified description of how these procedures are performed.

CONCLUSION

Thermal ablation, particularly RFA, is becoming an attractive option for managing a subgroup of solid thyroid nodules, while PEI has a role in managing thyroid cysts and a select group of PTMC. Their role in the algorithm of thyroid nodule management is still being refined and technical expertise will be essential to reproduce the reported results into everyday practice.

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.

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.

Radiofrequency Ablation and Autonomous Functioning Thyroid Nodules: Review of the Current Literature

OBJECTIVE

Autonomously functioning thyroid nodules (AFTNs) have long been treated with either surgery or radioactive iodine (RAI). Being an invasive procedure, even thyroid lobectomy for this condition is associated with complications such as anesthesia side effects, scarring, iatrogenic hypothyroidism, and injury to other structures. Similarly, RAI is associated with hypothyroidism and may require multiple courses. Therefore, minimally invasive techniques such as radiofrequency ablation (RFA) are being advocated as an alternative treatment for AFTNs. To date, only few studies have been published on this topic and are largely on European and Asian populations. The aim of this review is to assess the efficacy and safety of RFA as a potential alternative for treatment of AFTNs compared to conventional surgery and radioiodine.

METHODS/STUDY DESIGN

Comprehensive PubMed and Embase searches were performed using the following terms such as (autonomously functioning thyroid nodules and radiofrequency ablation), (radiofrequency ablation and hyperthyroidism), and (radiofrequency ablation and toxic thyroid nodule). Both prospective and retrospective studies were included based on the inclusion and exclusion criteria specified in the text.

RESULTS

Initially, 57 studies were identified and after excluding 47 studies, finally 10 studies were included in the review.

CONCLUSION

Although surgery remains the first line treatment for AFTN. However, RFA is a safe option compared to RAI or surgery, especially in patients who are high-risk surgical candidates or have absolute contraindications to RAI. Currently, trials with follow-up greater than or equal to 5 years are warranted. It will aid in formulating a standardized surveillance protocol and also generalize RFA's use for AFTN. Laryngoscope, 2021.

Radiofrequency ablation versus total thyroidectomy in patients with papillary thyroid microcarcinoma located in the isthmus: a retrospective cohort study

OBJECTIVE

This retrospective study aimed to examine the benefits and complications of radiofrequency ablation (RFA) in patients with papillary thyroid microcarcinoma (PTMC) in the isthmus.

METHODS

This retrospective study included patients with PTMC in the isthmus and treated at the Chinese People's Liberation Army hospital from 05/2014 to 05/2018. The patients were divided into the RFA and total thyroidectomy (TT) groups. The outcomes were operation-related complications, rate of recurrence, metastasis rate, and thyroid carcinoma-specific questionnaire of quality of life (THYCA-QOL).

RESULTS

Among 218 patients, 115 patients underwent RFA, and 103 underwent TT. The rates of disappearance of the ablation zone at 1, 3, 6, 12, and 18 months after RFA were 0.8% (1/115), 10.4% (12/115), 51.3% (59/115), 90.4% (104/115), and 100% (115/115), respectively. Surgical time, blood loss, hospital stays, and treatment costs were higher with TT than with RFA (all p < 0.001). The final THYCA-QOL score of the RFA group was significantly higher than in the TT group (p < 0.001). Minor pain at the operation site was seen in all patients in the RFA group. No distant metastasis was detected in all patients, but one patient in the RFA group had a recurrence after 6 months. The final THYCA-QOL score of the RFA group was significantly lower than in the TT group (p < 0.001).

CONCLUSION

These results suggest that RFA for PTMC in the isthmus had similar outcomes than TT. It will have to be confirmed in future studies.

Radiofrequency ablation and thyroid nodules: updated systematic review

PURPOSE

In the thyroid gland, radiofrequency ablation (RFA) is being applied to both benign nodules and cancers internationally, while interest is also growing in the West. Benign thyroid nodules (BTNs) may be candidates for intervention when symptoms develop. For differentiated thyroid cancers (DTC), surgery is currently the first-line treatment. However, for candidates with high surgical risk or those who refuse to undergo repeated surgery, newer techniques such as RFA are an option. Surgery is associated with complications including hypothyroidism, voice change, hypocalcemia, and a scar. RFA has been used in Asian and European institutions as an alternative to surgery, but is relatively new in North America. Although RFA is not associated with significant complications, few randomized control trials have assessed its efficacy. The studies to date suggest a low rate of severe complications and a small need for thyroid hormone replacement following RFA. Further large-scale studies focusing on a Western population are needed. The aim of this review is to evaluate the evidence with respect to the current studies and data about the safety and efficacy of radiofrequency ablation for the management of BTNs and DTC.

METHODS

We systematically searched the PubMed/MEDLINE, EMBASE, Clinical Queries, and Web of Science databases, for articles published up to April 30th, 2020.

RESULTS

Total of 75 studies that met the inclusion criteria were included in the review. Thirty-five studies focused on RFA use for solid nodules, 12 studies on predominantly cystic nodules, 10 for autonomously functioning thyroid nodules, and 18 studied were published on differentiated thyroid cancer.

CONCLUSIONS

RFA seems to be an effective and safe alternative to surgery in high-risk surgical patients with thyroid cancers and for selected BTNs. Additional trials with longer follow-up in North American patients are needed to validate its full role in the armamentarium of thyroid ologists.

Long-Term Results of Ultrasound-Guided Radiofrequency Ablation of Benign Thyroid Nodules: State of the Art and Future Perspectives-A Systematic Review

Background

Nearly 20 years after the first feasibility study, minimally invasive ultrasound (US)-guided therapeutic techniques are now considered as a safe and effective alternative to surgery for symptomatic benign thyroid nodules. Radiofrequency ablation (RFA) is one of the most widely used treatment in specialized thyroid centers but, due to the relatively recent introduction into clinical practice, there are limited long-term follow-up studies. Aim of our work was to review the outcomes of RFA on solid nonfunctioning and on autonomous thyroid nodules (AFTN) on a long-time period for assessing the results in term of efficacy, complications, and costs and to compare them to the current indications of RFA.

Methods

A systematic review was performed using EMBASE and Medline library data between 2008 and 2021. Seventeen studies evaluated RFA for the treatment of benign solid (nonfunctioning or autonomous) thyroid nodules, with an at least 18 months of follow-up. Data extraction and quality assessment were performed by two endocrinologist according to PRISMA guidelines. Anthropometric data, safety and efficacy parameters were collected.

Results

The majority of the studies was retrospective study and reported 933 nodules, mostly solid. Baseline volume ranged between 6.1 ± 9.6 and 36.3 ± 59.8 ml. Local analgesia was used and the time duration of the treatment was between 5 ± 2 and 22.1 ± 10.9 min. The volume reduction rate at 12 months ranged from 67% to 75% for the nodule treated with a single procedure and reached to 93.6 ± 9.7% for nodules treated with repeat ablations. The regrowth rate at 12 months ranged from 0% to 34%.

Conclusion

All the studies under examination consistently validated the long-term clinical efficacy and the substantial safety of RFA for the treatment of benign thyroid nodules. Thermal ablation, however, is an operator-dependent technique and should be performed in centers with specific expertise. The selection of the patients should be rigorous because the nodule size and the structural and functional characteristics influence the appropriateness and the outcomes of the treatment. Future perspectives as the treatment of micro-papillary thyroid cancer or cervical recurrence need further investigations.

Laser Ablation Versus Radiofrequency Ablation for Thyroid Nodules: 12-Month Results of a Randomized Trial (LARA II Study)

CONTEXT

Radiofrequency ablation (RFA) seems to achieve a significantly larger nodule volume reduction rate (VRR) than laser ablation (LA) in benign nonfunctioning thyroid nodules (BNTNs).

OBJECTIVE

To compare the efficacy and safety of both treatments at 12-month follow-up in patients with solid or predominantly solid BNTN.

METHODS

This was a single-center, 12-month, randomized, superiority, open-label, parallel-group trial conducted in an outpatient clinic. Sixty patients with a solitary BNTN or dominant nodule characterized by pressure symptoms/cosmetic problems were randomly assigned (1:1 ratio) to receive either a single session of RFA or LA. Twenty-9 patients per group completed the study. The main outcome measures were VRR and proportion of nodules with more than 50% reduction (technical success rate).

RESULTS

At 12 months, VRR was 70.9 ± 16.9% and 60.0 ± 19.0% in the RFA and LA groups, respectively (P = .024). This effect was confirmed in the linear regression model that was adjusted for age, sex, nodule baseline volume, and proportion of cellular components (RFA treatment: β = .390; P = .009). No significant between-group difference was observed in the technical success rate at 12 months after treatment. A statistically significant improvement was observed from the baseline to the 12-month follow-up for compression (RFA: 4.6 ± 2.6 and 1.3 ± 0.8, P < .001; and LA: 4.6 ± 2.1 and 1.6 ± 0.8, respectively, P < .001) and cosmetic (RFA: 3.4 ± 0.6 and 1.3 ± 0.5, P < .001; and LA: 3.4 ± 0.5 and 1.4 ± 0.6, P < .001) scores although the between-group differences were not significant.

CONCLUSION

RFA achieved a significantly larger nodule volume reduction at 12 months; however, the technical success rate was similar in the RFA and LA groups.

Efficacy of Microwave Ablation in the Treatment of Large (≥3 cm) Benign Thyroid Nodules

BACKGROUND

Large (≥3 cm) benign thyroid nodules usually cause clinical symptoms or cosmetic concerns and therefore require treatment. Microwave ablation (MWA) is a potential valid non-surgical treatment alternative, but there is a lack of evidence. Thus, this study is to evaluate the safety and efficacy of MWA in the treatment of large benign thyroid nodules.

METHODS

A retrospective study was conducted on 42 large benign thyroid nodules in 40 patients treated with MWA. We used the trans-isthmic approach and moving-shot technique to perform the procedure under ultrasound (US) guidance. Patients were followed by clinical and US examinations at 1, 3, 6, and 12 months after the MWA. Study outcomes were complications, volume reduction ratio (VRR), symptom and cosmetic scores, and the requirement of multiple MWA sessions.

RESULTS

There were 31 females and 9 males, with a median age of 46 years. The medians of largest diameter and volume of the nodules were 40 mm and 22 ml. Four (10%) minor complications were observed. The mean VRR was 75.1, 85.2, and 96.4% after 3, 6, and 12 months. The mean symptom and cosmetic scores dropped from 8.0 and 3.8 (before treatment) to 2.8 and 2.3 (at 12 months), respectively. Thirteen nodules (31%) required two MWA sessions.

CONCLUSIONS

MWA is safe, effective, and can be a good option to treat large benign thyroid nodules. More studies with large dataset and long follow-up are required to improve its safety and efficacy.

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.

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.

Update of Radiofrequency Ablation for Treating Benign and Malignant Thyroid Nodules. The Future Is Now

Thermal and chemical ablation are minimally invasive procedures that avoid removal of the thyroid gland and target symptomatic nodules directly. Internationally, Radiofrequency ablation (RFA) is among one of the most widely used thermal ablative techniques, and is gaining traction in North America. Surgery remains the standard of care for most thyroid cancer, and in the right clinical setting, Active Surveillance (AS) can be a reasonable option for low risk disease. Minimally invasive techniques have emerged as an alternative option for patients deemed high risk for surgery, or for those patients who wish to receive a more active treatment approach compared to AS. Herein, we review the literature on the safety and efficacy of RFA for treating benign non-functioning thyroid nodules, autonomously functioning thyroid nodules, primary small low risk thyroid cancer (namely papillary thyroid cancer) as well as recurrent thyroid cancer.

Twelve-Month Volume Reduction Ratio Predicts Regrowth and Time to Regrowth in Thyroid Nodules Submitted to Laser Ablation: A 5-Year Follow-Up Retrospective Study

Objective

Laser ablation is a therapeutic modality used to reduce the volume of large benign thyroid nodules. Unsatisfactory reduction and regrowth are observed in some treated nodules. The aim of the study was to evaluate the long-term outcomes of laser treatment for solid nodules during a 5-year follow-up period, the regrowth rate, and the predictive risk factors of nodule regrowth.

Materials and Methods

We retrospectively evaluated patients with benign, solid, cold thyroid nodules who underwent laser ablation and were followed-up for 5 years. According to the selection criteria, 104 patients were included (median baseline nodule volume, 12.5 mL [25.0–75.0%, 8–18 mL]; median energy delivered, 481.5 J/mL [25.0–75.0%, 370–620 J/mL]). Nodule volume, thyroid function test results, and ultrasound were evaluated at baseline and then annually after the procedure.

Results

Of 104 patients, 31 patients (29.8%) had a 12-month volume reduction ratio (VRR) < 50.0% and 39 (37.5%) experienced nodule regrowth. Of these 39 patients, 17 (43.6%) underwent surgery and 14 (35.9%) underwent a second laser treatment. The rate of nodule regrowth was inversely related to the 12-month VRR, i.e., the lower the 12-month VRR, the higher the risk of regrowth (p < 0.001). The mean time for nodule regrowth was 33.5 ± 16.6 months. The 12-month VRR was directly related to time to regrowth, i.e., the lower the 12-month VRR, the shorter the time to regrowth (p < 0.001; R² = 0.3516). Non-spongiform composition increased the risk of regrowth with an odds ratio of 4.3 (95% confidence interval [CI] 1.8–10.2; p < 0.001); 12-month VRR < 50.0% increased the risk of regrowth with an odds ratio of 11.7 (95% CI 4.2–32.2; p < 0.001).

Conclusion

The VRR of thyroid nodules subjected to similar amounts of laser energy varies widely and depends on the nodule composition; non-spongiform nodules are reduced to a lesser extent and regrow more frequently than spongiform nodules. A 12-month VRR < 50.0% is a predictive risk factor for regrowth and correlates with the time to regrowth.

Thermal Ablation of Benign Thyroid Nodules and Papillary Thyroid Microcarcinoma

Due to the increasing rates of physical examination and application of advanced ultrasound machines, incidences of benign thyroid nodules (BTNs) and papillary thyroid microcarcinoma (PTMC) were dramatically up-regulated in recent years. Thermal ablation (TA) has been widely used and regarded as a safe and effective method to eliminate or reduce BTNs and recurrent low-risk PTMC. However, conclusions using TA to treat primary PTMC are controversial. Recently, several long-term and prospective studies on TA treatment of BTNs and primary PTMC have been reported. Here, we review current literatures and progress on TA treatment of BTNs and PTMC and underline the way to get the best treatment outcomes, providing a comprehensive insight into the research progresses in this field.

A Novel Strategy for Single-Session Ultrasound-Guided Radiofrequency Ablation of Large Benign Thyroid Nodules: A Pilot Cohort Study

Background: Ultrasound-guided radiofrequency ablation (RFA) of thyroid nodules (TNs) is a minimally invasive procedure that has been widely used to induce volume reduction in symptomatic solid benign TNs. The goal of this study was to investigate a novel therapeutic approach for single-session ablation of large thyroid nodules (LTNs, vol > 20 ml). Methods: We performed a pilot cohort study of 21 patients with symptomatic solid benign LTNs (vol > 20 ml), who accepted ultrasound-guided RFA treatment between September 2018 and November 2019. RFA was performed using an 18-gauge internally cooled electrode with ultrasonographic guidance in a single session combined with intraoperative hydrodissection and immediate contrast-enhanced ultrasound (CEUS) to optimize safety and efficacy. Nodule volume was evaluated before ablation and at 1, 3, and 6 months after initial ablation, and all patients were asked to assess the cosmetic score (from 1 to 4) and symptom score (from 0 to 10) before ablation and at every follow-up after ablation. Results: At the 6 month follow-up, there was significant nodule volume reduction, from 27.49 ml ± 7.9 (standard deviation) to 3.82 ml ± 5.02 (p = 0.001). Cosmetic signs (p = 0.001) and pressure symptoms (p = 0.001) were significantly improved. All patients underwent RFA without any major complications, and very few patients developed a change in voice (2/21). However, the changes subsided within 1 month. Almost half of the patients received an additional RFA (11/21) treatment to achieve complete ablation on the intraoperative immediate CEUS evaluation. Conclusion: RFA is effective for treating LTNs (vol > 20 ml) and controlling clinical symptoms with a low complication rate. Patients were satisfied with cosmetic sign and pressure symptom improvement. The intraoperative hydrodissection and immediate CEUS represent a novel therapeutic approach for single-session ablation of LTNs.

Efficacy and safety of thermal ablation for autonomously functioning thyroid nodules: a systematic review and meta-analysis

BACKGROUND

Although thermal ablation has been regarded as an alternative treatment option for autonomously functioning thyroid nodules (AFTNs), the efficacy of this treatment in patients with AFTNs has not yet been systematically evaluated. In this systematic review and meta-analysis, we aimed to evaluate the efficacy and safety of thermal ablation in the treatment of AFTN, and identify the factors affecting the effectiveness of the treatment.

METHODS

Ovid-MEDLINE and Embase databases were searched for studies reporting the efficacy and safety of thermal ablation for patients with AFTN published up until January 6, 2020. Data extraction and quality assessment were performed by two radiologists according to PRISMA guidelines. The primary and secondary outcomes were to yield the pooled proportions of thyroid-stimulating hormone (TSH) normalization and pooled estimates of volume reduction rate (VRR), respectively. Subgroup analyses were performed to identify factors affecting the treatment efficacy.

RESULTS

This systematic review identified 411 AFTNs treated by thermal ablation in 391 patients in 14 studies. TSH normalization was achieved in 71.2% of patients and the volume reduction rate was 69.4% at a mean follow-up period of 12.8 months. No patients experienced hypothyroidism or a life-threatening complication during follow-up. Subgroup analyses according to nodule volume did not find a significant difference in TSH normalization (p = 0.54) or VRR (p = 0.94).

CONCLUSIONS

Thermal ablation is an effective and safe treatment method for patients with AFTNs. The nodule volume did not affect the efficacy of thermal ablation, and this result should be considered in future thermal ablation guidelines.

KEY POINTS

• Thermal ablation has good efficacy and safety in the treatment of autonomously functioning thyroid nodule. • The efficacy of thermal ablation was not affected by nodule volume.

2020 European Thyroid Association Clinical Practice Guideline for the Use of Image-Guided Ablation in Benign Thyroid Nodules

Standard therapeutic approaches for benign thyroid lesions that warrant intervention are surgery for cold and either surgery or radioiodine for autonomously functioning thyroid nodules (AFTN). Image-guided thermal ablation (TA) procedures are increasingly proposed as therapy options for selected clinical conditions. Due to mounting scientific evidence and widening availability, ETA considered it appropriate to develop guidelines for the use of TA in adult patients. TA procedures are well tolerated, but a dedicated training of the operators is required and information on possible complications needs to be shared with the patients. The following factors should be considered when weighing between observation, surgery, and TA for benign thyroid nodules. In solid non-hyperfunctioning nodules, TA induces a decrease in thyroid nodule volume, paralleled by improvement in symptoms. Nodule re-growth is possible over time and may necessitate repeat treatment, or surgery, in a dialogue with the patient. In AFTN, radioactive iodine is the first-line treatment, but TA may be considered in young patients with small AFTN due to higher probability of restoring normal thyroid function and avoidance of irradiation. In cystic nodules, ethanol ablation (EA) is the most effective and least expensive treatment. TA may be considered for cystic lesions that relapse after EA or have a significant residual solid component following drainage and EA. TA should be restricted to benign lesions that cause symptoms or cosmetic concern. Presently, laser and radiofrequency ablation are the most thoroughly assessed techniques, with similar satisfactory clinical results. Microwaves and high-intensity focused ultrasound therapy options remain to be fully evaluated.

Laser and radiofrequency ablations for benign and malignant thyroid tumors

A growing body of evidence is being published regarding the safety and efficacy of minimally invasive image-guided ablation techniques. While clinical applications of these techniques are increasing, international societies have started to publish treatment guidelines and to make efforts to standardize both terminology and reporting criteria for image-guided thyroid ablations. Laser ablation and radiofrequency ablation (RFA) are among the most common ablation techniques either for benign and malignant thyroid nodules. Unlike laser ablation and RFA in the treatment of benign thyroid nodules, where safety and efficacy have been widely demonstrated, evidence regarding local tumor control of thyroid malignancies is still limited. However, preliminary results are encouraging and image-guided thermal ablation techniques can be considered a valid alternative to surgery for the treatment of benign thyroid nodules and recurrent thyroid cancers. This review evaluates the basic concept of RFA and laser ablations, their techniques, clinical outcomes, and complications based on the suggestions of several society guidelines. Multidisciplinary collaboration remains critical to identify patients which may benefit from minimally invasive image-guided thermal ablations, especially if surgery or radioiodine therapy are not feasible options.

Radiofrequency ablation of functioning and non-functioning thyroid nodules: a single institution 12-month survey

PURPOSE

Radiofrequency (RF) treatment has played an increasing role in the management of benign thyroid nodules in recent years. The aim of this retrospective study was to evaluate the efficacy of RF treatment on volume reduction in functioning and non-functioning thyroid nodules.

PATIENTS AND METHODS

We reviewed the medical records of patients who had thyroid nodule RF ablation at our department between August 2017 and May 2018. Patients underwent a periodical follow-up with ultrasound examinations and thyroid function tests at 1, 3, 6 and 12 months from RF. Complications were assessed using the reporting standards of Interventional societies.

RESULTS

43 patients were submitted to thyroid nodule RF ablation treatment. Patients were subdivided into two groups, those with functioning (17 patients) or non-functioning nodules. At baseline (i.e. pre-RF treatment), the two groups of patients were superimposable for gender, age, BMI, nodule volume and maximum nodule diameter. The volume reduction of all 43 nodules was 69.1 ± 17.3% (range 26.0-94.5%) with no difference between functioning and non-functioning lesions (72.9 ± 18.1% vs 66.7 ± 16.7%, p = 0.254). A total energy delivered per nodule was 16.5 ± 6.8 kJ, with no difference between functioning and non-functioning lesions (14.5 ± 7.2 kJ vs. 18.2 ± 6.3 kJ, p = 0.083, respectively). No major complications were observed.

CONCLUSIONS

Radiofrequency ablation is a clinically effective and safe outpatient treatment in patients with benign nodules. In particular, we showed that a single treatment is effective in restoring euthyroidism in patients with autonomously functioning thyroid nodules.

Unfavorable Outcomes in Solid and Spongiform Thyroid Nodules Treated with Laser Ablation. A 5-Year Follow-up Retrospective Study

OBJECTIVE

Laser Ablation (LA) is a therapeutic modality for reducing the volume of large benign thyroid nodules. This retrospective study was aimed at assessing the outcome of LA in patients with benign nonfunctioning thyroid nodules in a 5-years follow-up.

METHODS

Sixty-two patients (47 females; mean age 54.7±12 yr) with benign cold thyroid nodules underwent LA from July 2009 to March 2012. Nodule volume, thyroid function test, and ultrasound were monitored at baseline, and at 3, 6 and 12 months after the procedure, then annually. After dividing nodules in solid and spongiform, we evaluated unfavourable outcomes: 1) nodule's volume reduction <50%; 2) need for surgery; 3) need for additive LA session (due to nodule re-growth with persistence of cosmetic concern or compressive symptoms).

RESULTS

Baseline volume did not differ between solid and spongiform nodules as well as energy delivered and the number of needles used. Unfavourable outcomes occurred in 24 patients (38.7%). Nineteen/ 24 (79.2%) patients who experienced unfavourable outcomes belonged to the solid nodules group (P<0.01). When considering only those who benefited from LA, the 5-years reduction was 59.7% for solid and 78.6% for spongiform nodules (P<0.05). One/6 patients who underwent surgery (solid nodules group) had a final diagnosis of Follicular Variant of Papillary Thyroid Cancer (FVPTC).

CONCLUSION

Large solid nodules, unlike spongiform, submitted to LA are characterized by a long-term unfavourable outcome and entail a potential risk of false negative cytologic results.

Radiofrequency Ablation on Autonomously Functioning Thyroid Nodules: A Critical Appraisal and Review of the Literature

Background: Thyroid nodules are an extremely common occurrence, as their prevalence in the general population is estimated to range between 50 and 70%. Some of these nodules are autonomously functioning such that they can cause hyperthyroidism over time. In this case, surgery and radioiodine represent the standard of care. Nevertheless, patients might have contraindications or be unwilling to undergo these treatments. Minimally-invasive ultrasound-guided techniques, such as laser and radiofrequency ablation (RFA), have been recently introduced into clinical practice as an alternative treatment for symptomatic benign thyroid nodules. Due to their efficacy and tolerability, these techniques have become increasingly available and their usage has been extended also to autonomously functioning thyroid nodules (AFTN). Methods: In this narrative review, we will describe the studies reporting the therapeutic effects of RFA on AFTN, the studies reporting how RFA compares to the other treatment modalities, as well as the current indications for the use of RFA in patients with AFTN. For this purpose, a comprehensive literature search was independently conducted by three investigators on PubMed, EMBASE, and the Cochrane Library from inception up to February 2020 to identify published articles concerning the effects of RFA on AFTN. Results and Conclusions: Current consensus statements and guidelines support the notion that RFA should be regarded as a first-line therapy for non-functioning benign thyroid nodules, while it remains a valid second-line option for AFTN treatment in case of contraindications or patient unwillingness to undergo surgery or radioiodine.

Novel Approaches for Treating Autonomously Functioning Thyroid Nodules

Benign thyroid nodules are exceedingly common in the adult population. Only a small percentage of nodules are toxic or autonomously functioning thyroid nodules (AFTNs). The options clinicians have for treating the symptoms of hyperthyroidism include anti-thyroidal medications, radioactive iodine, or surgery. Depending on the patient population treated, these options may not be suitable or have inherent risks that are undesirable to the patient. On the other hand, untreated hyperthyroidism can lead to osteoporosis, atrial fibrillation, emotional lability, and neurological consequences. Thus, we present a review of two novel safe and effective approaches for treating AFTN; one surgical (transoral endoscopic thyroid surgery) and one non-surgical (radiofrequency ablation), as a means for expanding our treatment armamentarium.

Radiofrequency Ablation for Benign Thyroid Nodules: 1-Year Follow-Up in 184 Patients

BACKGROUND

Benign thyroid nodules are common, and must be treated when symptomatic. Non-surgical minimally invasive modalities, including radiofrequency ablation (RFA), have been widely used with good results. The factors related to the efficacy of RFA are still debated. This study was to evaluate the safety, efficacy and related factors of RFA in the treatment of benign thyroid nodules.

METHODS

A retrospective single-center study was conducted on 251 benign thyroid nodules in 184 patients treated with RFA. The procedure was performed under ultrasound (US) guidance using the trans-isthmic approach and the moving-shot technique. Clinical and US examinations were performed at 1, 3, 6, 12 months, and then at 6 month intervals. Study outcomes were volume reduction ratio (VRR) and complications.

RESULTS

There were 153 women and 31 men included in the study. The mean age was 43.9 years. The median initial largest diameter and volume of nodules were 30 mm and 6.18 ml. The median length of follow-up was 12 months. Two minor complications were found. The mean VRR was 66.8; 74.3; and 81% after 3, 6, and 12 months, respectively. Initial solidity was a factor related to the efficacy: cystic nodules had higher VRR compared to solid ones.

CONCLUSIONS

RFA is safe, effective and can be used as a routine treatment for benign thyroid nodules. More prospective multicenter studies with long-term follow-up are required to improve the safety and efficacy of RFA.

Image-Guided Thyroid Ablation: Proposal for Standardization of Terminology and Reporting Criteria

Background: Image-guided tumor ablation is commonly performed in clinical practice. Trying to standardize terminology and data collection to enable a more reliable comparison among the different studies, in 2003, a document entitled "Image-Guided Tumor Ablation: Proposal for Standardization of Terms and Reporting Criteria" was published by the International Working Group on Image-Guided Tumor Ablation. Since then, ablations have evolved significantly, with the development of new technology and techniques and applications. This has included benign thyroid nodules, and their ablation has become increasingly accessible, not only among radiologists but also among other specialists involved in thyroid care, including endocrinologists and surgeons. This has resulted in further inhomogeneity in how data are presented and reported among different studies, resulting in a need for standardization to homogenize language and data reporting on the topic. Summary: In February 2018 in Milano, Italy, a meeting involving specialists concerned with minimally invasive treatments of thyroid lesions was organized, and the Italian Working Group on Minimally Invasive Treatments of the Thyroid was founded with the aim of establishing a collaborative network among all clinicians working in this field. The first work of this group is to present a proposal for standardization of terminology and reporting criteria on image-guided ablations to treat benign thyroid nodules. Conclusion: This proposal was drafted with the goal of providing guidance for standardized reporting of results in studies regarding image-guided thyroid ablations. We encourage adoption of this terminology worldwide, anticipating that this will facilitate improved communication and understanding within the field and stimulate further discussion on the topic over the next years.

Comparison between radioiodine therapy and single-session radiofrequency ablation of autonomously functioning thyroid nodules: A retrospective study

OBJECTIVE

To compare the efficacy of Radioiodine (RI) and Radiofrequency ablation (RFA) in the treatment of autonomously functioning thyroid nodules (AFTNs). End-points: nodule volume reduction (NVR) and thyroid function normalization.

DESIGN, PATIENTS AND MEASUREMENTS

Twenty-two patients (2:20 M:F; 51.9 ± 13.9 years) affected by 25 AFTNs, treated by RFA were retrospectively compared with 25 patients (8:17 M:F; 57.2 ± 12.8 years) affected by a single AFTN treated by RI. Both group showed analogous characteristics as to age, gender, toxic/pretoxic phase and pretreatment nodule volume (calculated by the ellipsoid formula). Thyroid hormone levels and autoimmune thyroid profile were assessed before treatment. A fixed RI activity of 555 MBq (15 mCi) was administered. RFA was performed with an 18G, single-tipped electrode, by the "modified moving shot technique." Thyroid hormones were assessed and the nodule post-treatment volume calculated 12 months after treatment.

RESULTS

No statistical difference was found between the post-treatment NVR by comparing RI and RFA (P = 0.69). The volume reduction rates were 68.4 ± 28.9% and 76.4 ± 16.9% after RI and RFA, respectively. As to the thyroid function, 5/25 patients developed clinical hypothyroidism after RI. After RFA, all the 22 patients silenced their AFTN and normalized the thyroid hormones. Subclinical hypothyroidism was recorded in two patients after both RI and RFA. Thus, the functional therapeutic success, defined as the restoration of euthyroidism, was achieved in 18/25 (72%) patients treated by RI and in 20/22 (90.9%) treated by RFA.

CONCLUSIONS

No statistical difference in NVR was found between RI and RFA. All patients responded to RI but 5/25 were "over-treated" developing hypothyroidism. RFA was effective in all patients with no case of post-treatment clinical hypothyroidism. No radiation exposure and lower risk of post-treatment hypothyroidism might make RFA the favourite option especially for young patients.

Minimally-invasive treatments for benign thyroid nodules: a Delphi-based consensus statement from the Italian minimally-invasive treatments of the thyroid (MITT) group

Benign thyroid nodules are a common clinical occurrence and usually do not require treatment unless symptomatic. During the last years, ultrasound-guided minimally invasive treatments (MIT) gained an increasing role in the management of nodules causing local symptoms. In February 2018, the Italian MIT Thyroid Group was founded to create a permanent cooperation between Italian and international physicians dedicated to clinical research and assistance on MIT for thyroid nodules. The group drafted this list of statements based on literature review and consensus opinion of interdisciplinary experts to facilitate the diffusion and the appropriate use of MIT of thyroid nodules in clinical practice. (#1) Predominantly cystic/cystic symptomatic nodules should first undergo US-guided aspiration; ethanol injection should be performed if relapsing (level of evidence [LoE]: ethanol is superior to simple aspiration = 2); (#2) In symptomatic cystic nodules, thermal ablation is an option when symptoms persist after ethanol ablation (LoE = 4); (#3) Double cytological benignity confirmation is needed before thermal ablation (LoE = 2); (#4) Single cytological sample is adequate in ultrasound low risk (EU-TIRADS ≤3) and in autonomously functioning nodules (LoE = 2); (#5) Thermal ablation may be proposed as first-line treatment for solid, symptomatic, nonfunctioning, benign nodules (LoE = 2); (#6) Thermal ablation may be used for dominant lesions in nonfunctioning multinodular goiter in patients refusing/not eligible for surgery (LoE = 5); (#7) Clinical and ultrasound follow-up is appropriate after thermal ablation (LoE = 2); (#8) Nodule re-treatment can be considered when symptoms relapse or partially resolve (LoE = 2); (#9) In case of nodule regrowth, a new cytological assessment is suggested before second ablation (LoE = 5); (#10) Thermal ablation is an option for autonomously functioning nodules in patients refusing/not eligible for radioiodine or surgery (LoE = 2); (#11) Small autonomously functioning nodules can be treated with thermal ablation when thyroid tissue sparing is a priority and ≥80% nodule volume ablation is expected (LoE = 3).