Radiofrequency Ablation for the Treatment of Autonomously Functioning Thyroid Nodules

Thyroid Nodule Rupture Following Radiofrequency Ablation for Benign Thyroid Nodules

Importance

Nodule rupture is a rare but serious complication of thyroid radiofrequency ablation (RFA). With growing adoption of thyroid RFA across the US, an understanding of thyroid nodule rupture (TNR) is crucial for recognition, management, and, ultimately, prevention.

Objective

To determine procedural and patient factors that may contribute to TNR and describe experiences in managing TNR while synthesizing existing literature.

Design, Setting, and Participants

This retrospective case series examined all RFA procedures for benign thyroid nodules performed by 2 attending physicians at a single academic referral center between December 2019 and January 2024. A total of 298 consecutive patients underwent RFA for benign thyroid nodules. Criteria for offering RFA included nodules with 2 benign fine-needle aspirations, no suspicious ultrasonography features, a greatest dimension of 2 cm or greater, compressive or cosmetic concerns, and accessibility to a straight needle.

Exposures

All RFAs were performed using ultrasonography guidance using the moving-shot technique and a 7-mm or 10-mm active tip.

Main Outcomes and Measures

The primary outcome was TNR, and measures were procedure, nodule, and patient characteristics that may have contributed to its pathogenesis. Secondary outcomes were nodule volume reduction, thyroid function, and management and sequelae of TNR. The hypothesis on the pathogenesis of TNR was formed before data collection.

Results

Six of 298 patients (2%; 4 women [67%]) with a mean age of 48.5 years (range, 34-65 years) experienced TNR for a mean of 36 days postprocedure (range, 19-54 days). The mean (SD) initial nodule volume among patients with TNR was 31.45 (16.52) mL, and 3 of 6 patients (50%) underwent prior lobectomy. All ruptures were anterior. All patients were treated conservatively, and none required surgery. Five patients recovered completely; the sixth and most recent patient was healing as of last follow-up.

Conclusions and Relevance

There are limited data on the etiology and optimal management of TNR. These 6 cases of anterior rupture suggest that a potential contributor to TNR is thermal and mechanical trauma exerted at the fulcrum point during the moving-shot technique. The use of a smaller active tip (eg, 7 mm) and cessation of energy delivery before this point may help avoid TNR. More robust reporting of this complication may clarify risk factors for and enhance prevention of TNR.

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.

The Comparison of Efficacy and Safety between Radiofrequency Ablation Alone and Ethanol Ablation Followed by Radiofrequency Ablation in the Treatment of Mixed Cystic and Solid Thyroid Nodule

Purpose

To compare the efficacy and safety of radiofrequency ablation (RFA) and ethanol ablation (EA) followed by RFA in treating mixed cystic and solid thyroid nodules.

Materials and Methods

We included 243 nodules from 243 patients who underwent RFA for mixed cystic and solid benign nodules. The nodules were divided into two groups (RFA alone and EA + RFA). We evaluated volume reduction rate (VRR), therapeutic success rate, improvement in symptomatic and cosmetic issues, complications, and adverse effects.

Results

The RFA group included 204 patients, and the EA + RFA group included 39 patients. The long-term success rates in the RFA only and EA + RFA groups were 90.2% and 97.4%, respectively. The mean VRR at the last follow-up in the RFA and EA + RFA groups were 81.6% and 87.2%, respectively. Therapeutic results were similar in both groups at the last follow-up. Cosmetic and symptomatic problems markedly improved in both groups. No major complications were observed.

Conclusion

Both RFA alone and EA + RA are safe and effective methods for treating mixed cystic and solid thyroid nodules, although EA + RFA is slightly more effective.

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

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

Protect the recurrent laryngeal nerves in US-guided microwave ablation of thyroid nodules at Zuckerkandl tubercle: a pilot study

BACKGROUND

To evaluate the safety and efficacy of US-guided microwave ablation in patients with thyroid nodules at Zuckerkandl tubercle.

METHODS

103 consecutive patients with thyroid nodules at Zuckerkandl tubercle (ZTTN) were enrolled in this study from November 2017 to August 2021. Prior to the surgery or US-guided microwave ablation (MWA), preoperative ultrasound visualization of the recurrent laryngeal nerve (RLN) and ZTTN was performed, the size and the position relationship between them were observed. Patients were followed up at 1, 3, 6, and 12 months after MWA and the volume reduction rates (VRR) of the thyroid nodules were analyzed.

RESULTS

All patients successfully had the RLN and ZTTN detected using ultrasound before surgery or ablation with a detection rate of 100%. For the 103 patients, the majority of ZTTN grades were categorized as grade 2, with the distance from the farthest outside of ZTTN to the outer edge of thyroid ranging between 6.0 and 10.0 mm. The position relationship between ZTTN and RLN was predominantly type A in 98 cases, with type D observed in 5 cases. After MWA, the median nodule volume had significantly decreased from 4.61 (2.34, 8.70) ml to 0.42 (0.15, 1.41) ml and the VRR achieved 84.36 ± 13.87% at 12 months. No nodules regrew throughout the 12-month follow-up period. Of the 11 patients experienced hoarseness due to RLN entrapment before ablation, 7 recovered immediately after separation of the RLN and ZTTN during MWA, 2 recovered after one week, and the other 2 recovered after two months.

CONCLUSIONS

The RLN is closely related to ZTTN and mainly located at the back of ZTTN. The RLN can be separated from ZTTN by hydrodissection during MWA. US-guided MWA is a safe and effective treatment for ZTTN.

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.

Ultrasonography-guided radiofrequency ablation of vascular malformations-The moving shot technique

Purpose

To describe a novel ultrasound-guided technique for percutaneous radiofrequency ablation of vascular malformations-the "moving shot technique."

Methods

Preliminary observational cohort study, conducted from June 1, 2019, to January 31, 2021, including all consecutive patients diagnosed with vascular malformations who were treated with ultrasound-guided radiofrequency ablation using the moving shot technique. Only patients who had undergone at least one unsuccessful previous treatment were included (sclerotherapy with ethanol/aethoxysklerol or embolization/surgery).

Results

Eight patients with a median age of 22 years (interquartile range, 13-31) were included. Patients had different vascular malformations consisting of 1 arteriovenous malformation, 4 venous malformations, and 1 each a mixed venous-lymphatic malformation, a glomuvenous malformation and a FAVA (fibroadipose vascular anomaly). Malformations were located at the limbs in 5 patients (62.5%), the subcutaneous/intramuscular tissue of the body in 2 patients (25%) and at the chin in 1 patient (12.5%). Clinical symptoms were pain in 8 patients (100%), swelling in 6 patients (75%), and partial immobility in 4 patients (50%). All patients showed an improvement of clinical symptoms after treatment with 7 (87.5%) being completely asymptomatic and 1 (12.5%) showing improvement of immobility and pain. No procedural complications, such as nerve damage or skin burns occurred.

Conclusion

The moving shot technique using ultrasonography-guided radiofrequency ablation is a promising technique for the interventional treatment of vascular malformations and should be validated in multicenter-approaches.

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.

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.

[Clinical Approach for Thyroid Radiofrequency Ablation]

Radiofrequency ablation (RFA) is a non-surgical treatment for symptomatic, benign thyroid nodules. This treatment works by heating and destroying the nodule tissue, which results in reduction of its size and alleviation of the symptoms involved. RFA is indicated for nodules which are confirmed to be benign on two or more cytological or histological examinations, and which result in clinical symptoms requiring medical treatment. It is associated with good short-term outcomes on one-year follow-up; however, 20%-30% of the nodules regrow after more than three years. Therefore, on the basis of long-term follow-up, management of regrowth is key to patient care following RFA. Regrowth is more likely to occur in nodules that are large in size prior to RFA, and in those with high or increased vascularity. Recently, new techniques such as hydrodissection, artery-first ablation, and venous ablation have been introduced to inhibit regrowth. In addition, appropriate criteria for additional RFA should be applied to manage regrowth and prolong its therapeutic effects. RFA is essentially an alternative to surgery; therefore, the ultimate goal of this procedure is to avoid surgery permanently, rather than to achieve temporary effects.

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.

Analysis and prediction of regrowth in benign thyroid nodules undergoing radiofrequency ablation: a retrospective study with a 5-year follow-up

OBJECTIVES

To evaluate the 5-year follow-up results of radiofrequency ablation (RFA) for benign thyroid nodules (BTNs), and construct pre- and postablation nomogram models to predict regrowth in BTNs undergoing RFA.

METHODS

According to the occurrence of regrowth, BTNs were divided into two subgroups, the regrowth group and the nonregrowth group, and the variables were compared between these two subgroups. Then, univariate and multivariate Cox regression analyzes were utilized to filter the independent prognostic factors of regrowth, which then were introduced into the pre- and postablation prognostic nomograms, respectively. The discrimination powers and prediction performances of the nomograms were appraised by receiver operating characteristic (ROC) curves and calibration charts.

RESULTS

The 5-year mean volume reduction rate was 88.80%, with a complication rate of 0.35% (7/200). Within 5 years of follow-up, the regrowth rate was 19% (38/200). Pre- and postablation prognostic nomograms were established to predict the probability of nonregrowth at 1, 3, and 5 years after RFA. The preablation nomogram included initial volume, perinodular vascularity, and high enhancement ring. The postablation nomogram incorporated total volume, perinodular vascularity, and energy applied per volume. The area under the ROC curves and concordance index values of these models were all above 0.7, indicating that the prognostic nomograms achieved satisfactory discrimination powers and prediction performances.

CONCLUSION

RFA for BTNs has long-term efficacy and safety under the influence of key techniques. The pre- and postablation nomograms constructed in the present study might facilitate clinical decision-making before RFA and for the follow-up management after RFA.

KEY POINTS

• Perinodular vascularity, rather than intranodular vascularity was an independent predictor of regrowth, both before and after the RFA procedure. • A high enhancement ring on preablation contrast-enhanced ultrasound was an independent predictor of regrowth. • Pre- and postablation nomograms might facilitate clinical decision-making before RFA and follow-up management after RFA.

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.

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.

Present Status of Thyroid Ablation in Europe: An International Survey among the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) Members

AIM

To evaluate the effective spread of image-guided thermal ablation in thyroid gland and to characterize its current perceptions among European interventional radiologists.

MATERIALS AND METHODS

A questionnaire with 29 multiple choice questions about thyroid ablation was sent as an E-blast to 4752 CIRSE members. Only those who completed the survey in all its parts were included in the study.

RESULTS

242/4752 (5.09%) participants (212 males and 30 females) completed and submitted the survey. A total of 160 subjects (66.1%) were familiar with any image-guided thermal ablations, but only 63 (26% of total population) usually perform thermal ablation for thyroid gland. Only 19.5% of the interviewed sample treats micropapillary thyroid tumours and the vast majority routinely uses radiofrequency ablation (84.4%).

CONCLUSION

There is a significant mismatch between thyroid ablation as reported by the literature and the relatively low percentage of interventional radiology actively performing such procedure in Europe. A considerable effort is required by the Cardiovascular and Interventional Radiological Society of Europe to fill this lack.

[Radiofrequency ablation of benign thyroid nodules]

Radiofrequency ablation is an effective tool to treat benign thyroid nodules up to about 100 ml. It is well tolerated and is - together with echopulse therapy - currently the most frequently used technique in Germany for the local therapy of benign thyroid nodules. Overall, a volume reduction of about 50 % to 70 % can be expected. Cystic nodules and mixed-pattern lesions respond slightly better than solid nodules. Initial volume, structure and echogenicity are important parameters influencing the therapeutic efficacy. Bipolar as well as monopolar methods are used - the choice of the method depends mainly on the personal experience. For bigger nodules, the bipolar technique is preferred. Cooled systems should be favored, especially when using larger probes. Serious side effects are rare (< 1 %) and transient in most cases.

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.

American Association of Clinical Endocrinology Disease State Clinical Review: The Clinical Utility of Minimally Invasive Interventional Procedures in the Management of Benign and Malignant Thyroid Lesions

OBJECTIVE

The objective of this disease state clinical review is to provide clinicians with a summary of the nonsurgical, minimally invasive approaches to managing thyroid nodules/malignancy, including their indications, efficacy, side effects, and outcomes.

METHODS

A literature search was conducted using PubMed and appropriate key words. Relevant publications on minimally invasive thyroid techniques were used to create this clinical review.

RESULTS

Minimally invasive thyroid techniques are effective and safe when performed by experienced centers. To date, percutaneous ethanol injection therapy is recommended for recurrent benign thyroid cysts. Both ultrasound-guided laser and radiofrequency ablation can be safely used for symptomatic solid nodules, both toxic and nontoxic. Microwave ablation and high-intensity focused ultrasound are newer approaches that need further clinical evaluation. Despite limited data, encouraging results suggest that minimally invasive techniques can also be used in small-size primary and locally recurrent thyroid cancer.

CONCLUSION

Surgery and radioiodine treatment remain the conventional and established treatments for nodular goiters. However, the new image-guided minimally invasive approaches appear safe and effective alternatives when used appropriately and by trained professionals to treat symptomatic or enlarging thyroid masses.

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.

Significance of radiofrequency ablation in large solid benign thyroid nodules

OBJECTIVE

The aim of this study is to explore efficacy and safety for radiofrequency ablation (RFA) among cases attacked by large benign solid thyroid nodules, mainly focusing on volume reduction, complication rate, and thyroid function.

METHODS AND MATERIALS

From June 2015 to November 2019, 24 patients with 25 large benign solid thyroid nodules (more than 25 ml) underwent single or sequential RFA in our institution. Eleven nodules achieved complete ablation after single RFA, whereas the other 14 nodules received sequential RFA. Volume reduction in large nodules was evaluated. Following single or sequential RFA, all patients received clinical and ultrasound evaluations, and the median follow-up duration among them was 23.5 months. Technical success, complication rate, and recurrence rate were assessed as well.

RESULTS

In single RFA group, volume reduction ranged from 62.6% to 99.4% (mean ± SD, 93.6 ± 9.9%) 6 months after RFA. In sequential RFA group, volume reduction ranged from 30.6% to 92.9% (mean ± SD, 67.4 ± 17.8%) after the first RFA and was between 83.4% and 98.4% (mean ± SD, 94.8± 3.8%) 6 months after the second RFA. The concentrations of FT3 and FT4 increased slightly 1 day after RFA and returned to normal level 1 month after.

CONCLUSIONS

Single or sequential RFA is safe and effective in treating large benign solid thyroid nodules (more than 25 ml) that cause obvious compressive symptoms. Hence, compression symptoms and cosmetic conditions could be effectively improved through single or sequential RFA without marginal recurrence.

Radiofrequency ablation and related ultrasound-guided ablation technologies for treatment of benign and malignant thyroid disease: An international multidisciplinary consensus statement of the American Head and Neck Society Endocrine Surgery Section with the Asia Pacific Society of Thyroid Surgery, Associazione Medici Endocrinologi, British Association of Endocrine and Thyroid Surgeons, European Thyroid Association, Italian Society of Endocrine Surgery Units, Korean Society of Thyroid Radiology, Latin American Thyroid Society, and Thyroid Nodules Therapies Association

BACKGROUND

The use of ultrasound-guided ablation procedures to treat both benign and malignant thyroid conditions is gaining increasing interest. This document has been developed as an international interdisciplinary evidence-based statement with a primary focus on radiofrequency ablation and is intended to serve as a manual for best practice application of ablation technologies.

METHODS

A comprehensive literature review was conducted to guide statement development and generation of best practice recommendations. Modified Delphi method was applied to assess whether statements met consensus among the entire author panel.

RESULTS

A review of the current state of ultrasound-guided ablation procedures for the treatment of benign and malignant thyroid conditions is presented. Eighteen best practice recommendations in topic areas of preprocedural evaluation, technique, postprocedural management, efficacy, potential complications, and implementation are provided.

CONCLUSIONS

As ultrasound-guided ablation procedures are increasingly utilized in benign and malignant thyroid disease, evidence-based and thoughtful application of best practices is warranted.

Factors related to the absorption rate of benign thyroid nodules after image-guided microwave ablation: a 3-year follow-up

PURPOSE

To assess the absorption rate and factors related to the development of benign thyroid nodules (BTNs) following image-guided microwave ablation (MWA).

MATERIALS AND METHODS

This retrospective study reviewed nodule efficacy in patients who underwent MWA of BTNs between January 2016 and January 2018. The endpoint was a third-year follow-up. Nodules were categorized into those showing complete absorption (volumes with less than 100% volume reduction ratio (VRR) and those showing partial absorption (100% VRR)). Univariable and multivariable regression analyses were carried out to identify variables that were associated with nodule absorption rates.

RESULTS

A total of 173 BTNs (median volume= 4.23 ml; 25-75 percentiles= 2.27-9.00 ml) from 173 patients were evaluated. 49.7% (86/173) of patients had nodules that became completely absorbed. The mean VRRs of all BTNs were 18.0%, 78.7%, 89.0%, 94.5%, and 97.1% at the 1-, 6-,12-, 24- and 36- month follow-ups. At the 3-year follow-up time point, nodule characteristics related to nodule VRR included nodule volume (adjusted odds ratio [AOR], 1.1 [95% CI: 1.0, 1.2]; p = 0.03) and nodule margin (AOR, 5.3 [95% CI: 1.8, 16.0]; p < 0.01). Treatment-related characteristics included energy per ml in nodular volume (AOR, 1.0 [95% CI: 1.0, 1.0]; p < 0.01) and blockage of peripheral flow (AOR, 3.3 [95% CI: 1.3 8.3]; p = 0.01).

CONCLUSIONS

US-guided image-guided MWA results in satisfactory long-term outcomes for the patients with BTNs. Factors related to nodule absorption rate were the volume and margin of the nodule, energy per ml in nodular volume and blockage of peripheral flow.

Efficacy and safety of ultrasound (US)-guided radiofrequency ablation of benign thyroid nodules

Background

We evaluated 45 benign thyroid nodules of 40 patients treated with radiofrequency (RF) ablation and followed up for 6 months. The inclusion criteria included unilateral or bilateral thyroid nodules with compression symptoms or cosmetic problems, cytological confirmation of benignity without atypical cells, and patient refusal or unfit for surgery. There was no predilection for the size, number, ultrasound nature of the nodules, (solid, cystic, or complex). RF ablation was performed using Mygen (M-3004) RF generator from RF Medical Co., Ltd, South Korea. The volume of the nodules and clinical problems were evaluated before and after the procedure. Complications and factors related to volume reduction were evaluated. The purpose of the study is to evaluate the efficacy and safety of US-guided radiofrequency (RF) ablation in the treatment of benign thyroid nodules.

Results

The volume reduction ratio (%) of the thyroid nodules was statistically significant. The mean VRR was 58.41 ± 15.27SD at 1 month, 73.26 ± 11.22SD at 3 months, and 82.54 ± 12.49SD at 6 months. P value was < 0.001. The radiofrequency ablation did not affect the normal thyroid function of the 38 patients who were euthyroid at the start of the study. Thyroid function normalized 1 month after ablation of the two autonomously functioning thyroid nodules. The compressive symptoms resolved in 22 patients (55%) and improved in the rest of the 18 patients (45%) with the median decreased from 8 (IQR 6–9), range 4–10 before treatment to 0 (IQR 0–1), range 0–3 after 6 months. Cosmetic problems improved in all 40 patients by P value < 0.001. The procedure had no sustained or life-threatening complications.

Conclusions

RF ablation was effective in reducing the size of the benign thyroid nodules and in controlling nodule-related compressive symptoms as well as cosmetic problems. There were no major complications sustained and no life-threatening complications or sequelae happened. RF ablation can be used as an alternative non-surgical minimally invasive treatment for patients with benign thyroid nodules.

Radiofrequency ablation of thyroid nodules: prospective cost-effectiveness analysis in comparison to conventional thyroidectomy

Objective

The objective of this study is to compare the total costs of surgery and radiofrequency (RF) ablation for the treatment of benign thyroid nodules.

Methods

This is a prospective randomized study comparing cases treated with US-guided RF ablation (cases) and surgery (control). They were selected and allocated to groups (thyroidectomy or radioablation) by permuted block randomization in blocks of five cases each.

Results

Five cases of RF Ablation were compared with five cases of thyroidectomies conducted in the same period. Similar complication rates were observed in both groups. Shorter operating time and hospital stay were observed for the RF group. In the evaluation of the total cost between procedures, radioblation represented 76% of the cost of partial thyroidectomy.

Conclusion

This study demonstrated that radioablation has a competitive cost, making it an effective alternative in the treatment of benign thyroid nodules.

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.

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.

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.

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.

Effects of energy-based ablation on thyroid function in treating benign thyroid nodules: a systematic review and meta-analysis

BACKGROUND

Whether thyroid function would be affected by ablation remains controversial. This systematic review and meta-analysis aimed to investigate the effects of energy-based ablation on thyroid function in treating benign thyroid nodules.

METHODS

EMBASE, PubMed, Cochrane Library, and Web of Science databases were searched. The mean difference (MD) or standard MD (SMD) was applied to assess changes in thyroid function, thyroglobulin (Tg), and antibodies after ablation. RevMan version 5.3 was used for data synthesis.

RESULTS

Forty-two studies involving 6380 patients were eligible. The pooled results revealed significant decrease of 1-day thyroid-stimulating hormone (95% CI, -0.67 to -0.14), significant increase of 1-day, 1-week, and 1-month free thyroxine (95% CI, 1.57 to 5.28; 95% CI, 0.61 to 2.42; 95% CI, -0.76 to -0.15), 1-day and 1-week Tg level (95% CI, 0.40 to 0.81; 95% CI, 0.21 to 1.29), 6-month anti-thyroglobulin antibodies (95% CI, 0.02 to 0.26), 1- and 3-month thyroperoxidase antibody (95% CI, 0.02 to 0.22; 95% CI, 0.17 to 0.43), and 1-day, 1-, and 3-month thyrotrophin receptor antibody (95% CI, 0.10 to 0.43; 95% CI, 0.00 to 0.30; 95% CI, 0.13 to 0.36) after ablation. No statistically significant differences were found in these six indicators in the longer term. The results of subgroup analysis were similar to the pooled results. No significant publication bias was found.

CONCLUSIONS

Energy-based ablation was more likely to have negative effects on thyroid function and antibodies and led to transient increase in Tg level in the short term. However, most of the patients would not develop any thyroid dysfunction in the long-term follow-up.

CT-based quantitative evaluation of the efficacy after radiofrequency ablation in patients with benign thyroid nodules

OBJECTIVE

The purpose of this study was to evaluate the usefulness of CT for quantitative assessment of the neck structures after RFA in patients with benign thyroid nodules.

MATERIALS AND METHODS

This single-center, retrospective cohort study included 38 patients with benign thyroid nodules who had received RFA and had available pre- and post-treatment CT images. Changes in the tracheal anteroposterior (AP)/transverse diameter ratio, cross-sectional tracheal area, midline deviation of the trachea, and anterior neck angle after RFA were quantitatively measured using CT. Volume reduction rates (VRRs) for the thyroid gland and nodules were measured using CT and US, respectively, and the intraclass correlation coefficient (ICC) was calculated. The paired Wilcoxon signed-rank test was used to compare pre- and post-treatment CT-based measurements, and univariate linear regression analysis was performed to determine the association of VRR with the mean delivered radiofrequency energy, number of RFA sessions, and initial thyroid volume.

RESULTS

After RFA, the tracheal AP/transverse diameter ratio and midline deviation were significantly decreased while the tracheal area and anterior neck angle were significantly increased (all, p < 0.001). The thyroid volume reduction was also significant (VRR, 42.1% ± 21.1%, p < 0.001), with moderate consistency between the CT-based thyroid VRR and US-based nodule VRR (ICC = 0.68, 95% confidence interval = 0.38-0.83, p < 0.001). The mean delivered radiofrequency energy (p = 0.565), number of RFA sessions (p = 0.209), and initial thyroid volume (p = 0.363) showed no significant association with VRR.

CONCLUSION

CT-based quantitative assessments may be useful for evaluating improvements in the neck structures after RFA for benign thyroid nodules.

Radiofrequency Ablation of Benign Thyroid Nodules: Recommendations from the Asian Conference on Tumor Ablation Task Force - Secondary Publication

Radiofrequency ablation (RFA) is a thermal ablation technique widely used for the management of benign thyroid nodules. To date, five academic societies in various countries have reported clinical practice guidelines, opinion statements, or recommendations regarding the use of thyroid RFA. However, despite some similarities, there are also differences among the guidelines, and a consensus is required regarding safe and effective treatment in Asian countries. Therefore, a task force was organized by the guideline committee of the Asian Conference on Tumor Ablation with the goal of devising recommendations for the clinical use of thyroid RFA. The recommendations in this article are based on a comprehensive analysis of the current literature and the consensus opinion of the task force members.

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.

Predictor Analysis in Radiofrequency Ablation of Benign Thyroid Nodules: A Single Center Experience

Purpose

To confirm the efficacy of ultrasound (US) guided radiofrequency ablation (RFA) in the treatment of benign thyroid nodules, we evaluated as primary outcome the technical efficacy and clinical success in a single center dataset. The secondary outcome was to find a correlation between nodules' pre-treatment features and volume reduction rate (VRR) ≥75% at 12 months after RFA and during follow-up period.

Methods

This retrospective study included 119 consecutive patients (99 females, 20 males, 51.5 ± 14.4 years) with benign thyroid nodules treated in our hospital between October 2014 and December 2018 with a mean follow-up of 26.8 months (range 3-48). Clinical and US features before and after RFA were evaluated by a US examination at 1, 3, 6, 12 months and annually thereafter up to 48 months.

Results

The median pre-treatment volume was 22.4 ml; after RFA we observed a statistically significant volume reduction from the first month (11.7 ml) to the last follow-up (p < 0.001 for all follow-up times). The median VRR was 47.1, 55.3, 61.2, 67.6, 72.8, 71.3, and 62.9% at 1, 3, 6, 12, 24, 36, and 48 months of follow-up respectively, showing a progressive significant improvement up to 24 months (VRRs 1 vs 3 months, 3 vs 6 months and 6 vs 12 months p < 0.001, 12 vs 24 months p = 0.05) while no differences at 24 vs 36 and 36 vs 48 months were observed. Symptoms improved significantly (complete resolution 64.35%, partial resolution 35.65%), and neck circumference was reduced as compared to pre-treatment (p < 0.001). Lower pre-treatment neck circumference (37.5 vs 36.0 cm, p = 0.01) was a positive predictor of VRR ≥75% at 12 months. Macrocystic echostructure (HR 2.48, p 0.046) and pre-treatment volume >22.4 ml (HR 0.54, p 0.036) were found to be independent positive and negative predictors of VRR ≥75% respectively. One-month post RFA VRR ≥50% represented the best positive predictor of technical success.

Conclusions

This study confirmed the efficacy of RFA in the treatment of benign thyroid nodules. In particular we show that by selecting macrocystic nodules smaller than 22.4 ml better long-term response can be achieved, which is predicted by an early shrinkage of the nodule.

RFA and benign thyroid nodules: Review of the current literature

Benign thyroid nodules (BTNs) are commonly found in the general population. They are usually asymptomatic and their incidence has increased as a result of wide-spread use of ultrasound. Benign nodules are typically monitored clinically until they increase in size, resulting in compressive symptoms warranting surgery. However, although surgery is generally well-tolerated and of low-risk, it is associated with a small risk for several complications including hypothyroidism, nerve injury, hematoma, injury to other structures and wound infection. Recently, newer image-guided ablation techniques including radiofrequency ablation (RFA) have been introduced. RFA has a similar safety profile when compared to surgery and has shown promising results in challenging surgical candidates. Though several studies have been published in Asian and European countries on the efficacy of RFA, limited data is available on the North American population. The aim of the study is to review the current literature establishing the clinical outcomes and safety of RFA for benign nodules.

LEVEL OF EVIDENCE

V.

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.

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.

Continuous neuromonitoring during radiofrequency ablation of benign thyroid nodules provides objective evidence of laryngeal nerve safety

INTRODUCTION

The recurrent laryngeal nerves(RLN) run immediately posterior to the thyroid capsule and could be injured during thyroid radiofrequency ablation(RFA). This study assesses whether RLN functional integrity is altered during RFA using continuous intraoperative neuromonitoring(CIONM).

METHODS

Prospective case series of twenty nodules treated with RFA under general anesthesia utilizing the laryngeal adductor reflex(LAR) for CIONM.

RESULTS

Thirteen nodules abutted the posterior thyroid capsule and 'danger triangle' for RLN injury. The ablative field did not breach the posterior capsule; 40 W was the maximal power used adjacent to the capsule. No patient experienced significant LAR amplitude alterations. Pre and postoperative laryngoscopy and voice assessments were comparable. At 12 months' median follow-up, no patient displayed posterior nodule regrowth.

CONCLUSIONS

This prospective case series supports the premise that benign nodule RFA is safe with regards to RLN functional integrity provided the posterior capsule is not breached by the ablation zone and posterior power is ≤ 40 W.

Feasibility of Adjustable Electrodes for Radiofrequency Ablation of Benign Thyroid Nodules

Objective

The purpose of this study was to evaluate a novel radiofrequency ablation (RFA) application utilizing an adjustable electrode for treatment of benign thyroid nodules.

Materials and Methods

From April 2011 to December 2018, 21 patients underwent RFA treatment on 21 thyroid nodules, utilizing an 18-gauge internally cooled electrode equipped with a size adjustable active tip. The peripheral nodule portions were ablated with the moving-shot technique and a shorter active tip, and the nodule centers were ablated with the fixed technique and a longer active tip. We assessed parameters including characteristics of the treated nodules, use of variablesized active tips, volume reduction rate, therapeutic success rate, and post-procedural complications. The therapeutic success rate was defined as a > 50% volume reduction of the initial nodule volume at the 6- or 12-month follow-up.

Results

The treated thyroid nodules were large enough to cause symptoms (mean volume, 29.6 mL). Two types of active tips per session were used for all nodules. The mean volume reduction rate at the last follow-up was 68.3 ± 4.4% and our therapeutic success rate was 90.5%. Both symptoms and cosmetic scores decreased significantly. Minor complications in three patients were recorded during and after the procedure.

Conclusion

This initial study demonstrated that an adjustable electrode for RFA of benign thyroid nodules effectively and safely resulted in volume reduction.

Double-Needle Lavage for Effective Treatment of Difficult-Aspiration Thyroid Cystic Nodules: A Single-Center Controlled Trial

PURPOSE

To explore the safety and efficacy of double-needle lavage (DNL) in the treatment of difficult aspiration thyroid cystic nodules.

MATERIALS AND METHODS

This single-center, prospective, randomized controlled trial was conducted using 100 thyroid cysts from 100 patients who were treated in our hospital from January 2018 to August 2019. These patients were placed into 2 groups; group A including 40 patients treated with single-needle aspiration (SNA), and group B including 60 patients treated with DNL. The safety and efficacy of these 2 aspiration methods were compared.

RESULTS

Ten patients in group A that did not benefit from SNA were transferred to group B. No complication occurred in either group. Notably, DNL showed significantly higher efficacy than SNA. This was evidenced by the higher extraction rate of materials in the capsule (A vs B, 91 ± 6.51% vs 98.45 ± 1.74%, P < .001) and overall nodule volume reduction rate in group B (A vs B, 87.54 ± 7.84% vs 95.62 ± 3.66%, P < .001). In group B, patients who received DNL treatment with 2 needles pointed at the upper and lower extremes of the cystic nodules (B2) exhibited significantly better aspiration effects compared to patients in which the 2 needles were pointed at the same ultrasound plane (B1) (P < .05), especially for patients with maximum diameter of nodules ≥3 cm (P < .01).

CONCLUSIONS

DNL treatment could efficiently and safely replace cystic material from thyroid gland. Moreover, our results indicate that DNL treatment in which 2 needles are pointed at the 2 extremes of cystic nodules yields higher efficacy in patients with maximum diameter of nodules ≥3 cm.

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

Radiofrequency ablation (RFA) is a thermal ablation technique widely used for the management of benign thyroid nodules. To date, five academic societies in various countries have reported clinical practice guidelines, opinion statements, or recommendations regarding the use of thyroid RFA. However, despite some similarities, there are also differences among the guidelines, and a consensus is required regarding safe and effective treatment in Asian countries. Therefore, a task force was organized by the guideline committee of the Asian Conference on Tumor Ablation with the goal of devising recommendations for the clinical use of thyroid RFA. The recommendations in this article are based on a comprehensive analysis of the current literature and the consensus opinion of the task force members.

Clinical applications of Doppler ultrasonography for thyroid disease: consensus statement by the Korean Society of Thyroid Radiology

Doppler ultrasonography (US) is widely used for the differential diagnosis of thyroid nodules, metastatic cervical lymph nodes in patients with thyroid cancer, and diffuse parenchymal disease, as well as for guidance in various US-guided procedures, including biopsy and ablation. However, controversies remain regarding the appropriate use and interpretation of Doppler US. Therefore, the Korean Society of Thyroid Radiology organized a taskforce to develop a consensus statement on the clinical use of Doppler US for thyroid disease. The review and recommendations in this article are based on a comprehensive analysis of the current literature and the consensus of experts.

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.