Thyroid Radiofrequency Ablation: Updates on Innovative Devices and Techniques

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Resolution of Sleep Apnea After Radiofrequency Ablation of Goiter

Background: Obstructive sleep apnea (OSA) and nontoxic multinodular goiter are conditions that often coexist. Treatments of both conditions have evolved over time, but continuous positive airway pressure (CPAP), oral appliances, or surgical therapy are often needed. Radiofrequency ablation (RFA) of the soft palate and base of tongue has been applied as a newer alternative therapy for OSA. RFA is also an increasingly used approach for thyroid nodules and goiter, but previously had no known connection to OSA. Case Presentation: A 59-year-old female with a known history of multinodular goiter and moderate OSA was referred to our endocrine surgery clinic. The goiter was found to have mediastinal extension, documented longitudinal growth of the dominant nodule, cosmetic deformity of the neck, and tracheal deviation. The patient underwent thyroid RFA as nonoperative treatment for her goiter. Within a month of her procedure, she also self-reported a subjective reduction in apneic events and later underwent a formal home sleep study demonstrating an apnea-hypopnea index (AHI) change from 15.8/h at diagnosis to 2.9/h currently, signifying resolution of her OSA. Her treated nodule had 92% volume reduction on 18-month follow-up visit. Conclusion: To our knowledge, this is the first reported case of OSA cured in a patient undergoing RFA for goiter. Goiter-associated sleep apnea remains inadequately described in the literature and warrants further investigations on prevalence and management. Thyroidectomy continues to be the definitive treatment for goiter, with some studies suggesting secondary efficacy for OSA. RFA is now established as a first-line option for symptomatic thyroid nodules, but previously had no described benefit to OSA symptoms. This report illustrates that RFA of thyroid nodules could be offered to patients as both an effective nonsurgical option for goiter as well as a potential cure for their OSA to free them from nightly CPAP usage.

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

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

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

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

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

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.

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

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

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

KEY POINTS

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

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

OBJECTIVE

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

STUDY DESIGN

Porcine animal study.

SETTING

University animal laboratory.

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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

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

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.

Thermal Ablation for Papillary Thyroid Carcinoma

Importance

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

Objective

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

Design, Setting, and Participants

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

Main Outcomes and Measures

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

Results

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

Conclusions and Relevance

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

Hydrodissection technique for pain relief during peri-microwave ablation in patients with subpleural non-small cell lung cancers

PURPOSE

This study aimed to assess the application value of the hydrodissection technique (HT) for pain relief during peri-microwave ablation (MWA) in patients with subpleural non-small cell lung cancers (NSCLCs).

METHODS

This retrospective study comprised 218 patients with subpleural NSCLCs who underwent computed tomography (CT)-guided percutaneous MWA. The patients were divided into two groups: HT-assisted MWA (HT group) and local pleural anesthesia (LPA)-assisted MWA (LPA group). Differences in the effective rates of pain relief during MWA, visual analog scale (VAS) scores post-MWA, complications, and complete ablative rates were assessed.

RESULTS

The HT group comprised 101 patients (62 males and 39 females; mean age, 61.93 ± 10.57 years), while the LPA group comprised 117 patients (66 males and 51 females; mean age, 62.95 ± 11.16 years). The effective rate of pain relief in the HT group (82/101 patients, 81.19%) was significantly higher than that in the LPA group (66/117 patients, 56.41%), (p < 0.0001). The VAS scores at 6, 12, 24, and 48 h post-MWA were not statistically different between the two groups. The incidence of pneumothorax (grade ≥3) was significantly lower in the HT group (11/101 patients, 10.89%) than in the LPA group (27/117, 23.07%), (p = 0.0161). The complete ablative rates at 1, 3, 6, 12, and 24 months post-MWA were comparable of two groups.

CONCLUSIONS

These results indicate that HT-assisted MWA of patients with subpleural NSCLCs could effectively provide pain relief and decrease the occurrence of pneumothorax, yielding a satisfactory local therapeutic response.

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

OBJECTIVE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL RELEVANCE STATEMENT

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

KEY POINTS

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

Laser ablation for spongiform thyroid nodules: identifying baseline nodule volume and energy to be delivered for successful treatment

BACKGROUND

Laser ablation (LA) is a minimally invasive treatment. It has been widely used since the early 2000s to induce volume reduction of symptomatic benign thyroid nodules. Up to 40% of laser-treated nodules have been reported to achieve a volume reduction of <50% (technique inefficacy) at 12 months and tend to regrow over time.

OBJECTIVE

This study aimed to assess the optimal baseline volume and energy to be delivered to minimize technique inefficacy.

METHODS

This was a retrospective study. Data were collected, including baseline volume, energy delivered, and 12-month volume reduction ratio (VRR) of spongiform nodules (EU-TIRADS 2) treated with LA between 2010 and 2020. Based on these data, the optimal baseline volume and energy to be delivered were calculated to maximize the rate of nodules with technique efficacy (VRR ≥ 50% at 12-month follow-up).

RESULTS

A total of 205 patients with spongiform nodules were included in this study. The energy delivered was positively associated with VRR. However, no association was observed between baseline volume and VRR. Delivering energy ≥500 J/mL to nodules with a mean baseline volume of 11.4 ± 4 mL resulted in technique efficacy in 83% of cases.

CONCLUSION

Treating spongiform nodules with a baseline volume of ≤15 mL and delivering energy ≥500 J/mL are key factors for achieving a relevant rate of technique efficacy.

Current role of interventional radiology in thyroid nodules

Thyroid nodules are a prevalent health issue in society. Interventional radiological methods are successfully applied for both the diagnosis and treatment of nodules. Diagnostically, a fine-needle aspiration biopsy and a core needle biopsy can be performed to ascertain the benign or malignant nature of a lesion. In recent years, imaging-guided percutaneous treatment methods have become popular in the treatment of thyroid nodules. Aspiration, ablation, and embolization are techniques employed in the treatment process. In this study, we aimed to discuss the current role of interventional radiology in the diagnosis and treatment of thyroid nodules, which occupy an important place in clinical practice.

A Training Course for Simulating Head and Neck Ultrasound-Guided Procedures Using a Gelatin Phantom Model

OBJECTIVES

Ultrasound (US)-guided procedures can be used in the evaluation and treatment of neck masses. However, these procedures need to be practiced before being executed on humans. The aim of this study is to evaluate the efficacy of a training program using a gelatin phantom to practice US-guided procedures.

METHODS

This program included a lecture and practice with a gelatin phantom. We recruited doctors from different hospitals to practice US-guided procedures, including fine-needle aspiration (FNA), core needle biopsy (CNB), percutaneous ethanol injection (PEI), and radiofrequency ablation (RFA). We used a questionnaire with a 5-point scale to evaluate the effectiveness of practicing US-guided procedures under a gelatin phantom.

RESULTS

Forty-four doctors participated, and 37 of them completed the questionnaires. After training, the mean (SD) scores of the doctors were 4.68 (0.47) for "Satisfaction with this course," 4.54 (0.61) for "Ease in practicing FNA&CNB using the phantom," 4.49 (0.61) for "Ease in practicing PEI using the phantom," 4.49 (0.65) for "Ease in practicing RFA using the phantom," and 4.57 (0.55) for "The course effectively familiarizing participants with US-guided procedures." Participants without experience in US examination had higher scores than those with previous US experience, but the difference was not statistically significant.

CONCLUSION

A combination of lectures and hands-on practice of US-guided procedures using a gelatin phantom is an effective educational method for doctors interested in head and neck US. After the training program, doctors gained a better understanding of the necessary steps and skills required for these procedures. They can correctly insert the instruments into the target lesion and perform different US-guided procedures.

<italic>In vitro</italic> heat insulation efficacy of 5% dextrose versus 0.9% saline during radiofrequency ablation

PURPOSE

This study compared the efficacy of heat insulation between 5% dextrose and 0.9% saline in radiofrequency ablation (RFA). Accordingly, temperature variations and maximum temperatures were assessed at identical distances and heat field distributions.

METHODS

Cubes of porcine liver tissue, measuring 10 mm across, were selected to precisely align the ablation boundary with the tissue boundary. An 18-gauge electrode with a 7-mm tip was inserted into each cube (10 per group) in a stainless-steel cup containing 40 mL of 5% dextrose or 0.9% saline. Fixed ablation was performed for 3 minutes using continuous mode at 30 W, simulating the typical thermal environment during thyroid RFA. Real-time temperature measurements were recorded by sensors positioned 0, 1, 3, and 5 mm from the cube's edge. A comparative analysis was conducted to assess the maximum temperature, temperature variation, and duration of temperatures exceeding 42℃.

RESULTS

In both groups, the temperature curve declined with increasing distance from the edge of the ablated tissue. However, 0.9% saline exhibited higher maximum temperatures at 1, 3, and 5 mm compared to 5% dextrose (1 mm: 44.55°C±5.25°C vs. 34.68°C±3.07°C; 3 mm: 39.64°C±2.53°C vs. 29.22°C±2.21°C; 5 mm: 38.86°C±2.14°C vs. 28.74°C±2.51°C; all P<0.001). Considering a nerve injury threshold of 42°C, the 0.9% saline also displayed a greater proportion of samples reaching this temperature and a longer duration of temperatures exceeding it (P<0.05).

CONCLUSION

The heat insulation efficacy of 5% dextrose at 1-5 mm exceeds that of 0.9% saline at identical distances and in a common thermal environment during thyroid RFA.

Value of radiofrequency ablation for treating locally recurrent thyroid cancer: a systematic review and meta-analysis for 2-year follow-up

PURPOSE

To evaluate the safety and efficacy of radiofrequency ablation (RFA) in treating locoregional recurrent thyroid cancer (LRTC) after a 2-year follow-up time.

METHODS

PubMed, Embase and Cochrane Library were searched from inception until 20 September 2022 to find studies reporting the safety and efficacy of RFA in LRTC patients after a 2-year follow-up. Two radiologists performed the data extraction and methodological quality assessment according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

We analyzed 6 studies, 229 LRTC patients with 319 locally recurrent tumors were treated with RFA. The mean follow-up time of each study was ≥24 months. The pooled changes in the largest diameter and volume were 7.22 mm (95% confidence interval (CI), 6.35-8.09 mm) and 164.28 mm3 (95% CI, 87.78-240.77 mm3), respectively; the pooled volume reduction rate was 95.03% (95% CI, 87.56-102.49%). The total complete disappearance rate after treatment was 92% (95% CI, 83-100%). The pooled decrease of serum thyroglobulin levels was 0.02 ng/ml (95% CI, -0.00-0.04 ng/ml). The pooled proportion of recurrence rate was 6% (95% CI, 0-13%). The pooled complication rate was 5% (95% CI, 0-10%). The major complications were voice change and hoarseness, only one patient developed permanent vocal cord paralysis; minor complications were cough and pain.

CONCLUSIONS

Ultrasound-guided RFA is an effective and safe treatment for LRTC based on 2-year follow-up results.

Efficacy and Safety of Thermal Ablation for Solitary Low-Risk T2N0M0 Papillary Thyroid Carcinoma

OBJECTIVE

To evaluate the efficacy and safety of thermal ablation in treating solitary low-risk T2N0M0 papillary thyroid cancer (PTC) and compare the outcomes of microwave ablation (MWA) and radiofrequency ablation (RFA).

MATERIALS AND METHODS

This retrospective, single center study involved 34 patients (age: 40.0 ± 13.9 years; 28 female) who had low-risk T2N0M0 PTC with a maximum diameter >2 cm and ≤4 cm and underwent MWA (n = 15) or RFA (n = 19) from November 2016 to April 2023. The primary outcomes were the cumulative rate of disease progression and delayed surgery rates. In contrast, the secondary outcomes included changes in tumor size, cumulative rate of complete tumor disappearance, and complication rates.

RESULTS

The median follow-up period was 18.0 months (interquartile range [IQR]: 9.0-40.0 months). At 12 months, the median volume reduction rate of the ablation zone was 74.2% (IQR: 53.7%-86.0%). Disease progression was noted in two patients within 1 year, including one patient with local tumor progression post-RFA and one with a new tumor post-MWA, resulting in a constant cumulative disease progression rate of 8.8% (95% confidence interval [CI]: 0%-19.8%) throughout the remaining follow-up period. Both patients were subsequently treated with additional ablation and did not require surgery. The cumulative rates of complete tumor disappearance at 1, 3, and 5 years were 4.0% (95% CI: 0%-11.4%), 26.8% (95% CI: 2.7%-44.9%), and 51.2% (95% CI: 0%-79.1%), respectively. No significant differences were observed in the disease progression (P = 0.829) or complete tumor disappearance (P = 0.633) rates between the MWA and RFA groups. Complications occurred in 14.7% (5/34) of patients presenting with transient hoarseness. RFA had a higher but not statistically significant complication rate than MWA did (21.1% [4/19] vs. 6.7% [1/15]; P = 0.355).

CONCLUSION

Both MWA and RFA demonstrated promising short-term outcomes in terms of efficacy and safety in treating solitary low-risk T2N0M0 PTC, with no significant differences.

Long-term comparison of image-guided thermal ablation vs. lobectomy for solitary papillary thyroid microcarcinoma: a multi-center retrospective cohort study

BACKGROUND

Image-guided thermal ablation has been applied in patients with papillary thyroid microcarcinoma (PTMC) who refuse surgery or active surveillance. However, evidence to support ablation is limited by single-center designs and a lack of long-term data. The purpose of this study was to compare long-term outcomes between ablation and lobectomy for patients with solitary PTMC.

MATERIALS AND METHODS

This multi-center retrospective study included 1021 consecutive patients with solitary PTMC who underwent ablation ( n =444) or lobectomy ( n =577) at the four university-affiliated hospitals. The primary outcomes were disease progression [lymph node metastasis (LNM), recurrent tumors, persistent tumors and distant metastasis] and disease-free survival (DFS). Secondary outcomes were complications, hospitalization, procedure time, estimated blood loss and cost. The two groups were compared using propensity score matching.

RESULTS

After matching, no significant differences were observed in disease progression (4.7% vs. 3.4%, P =0.307), LNM (1.6% vs. 1.6%, P =1.000), recurrent tumors (2.9% vs. 1.8%, P =0.269), persistent tumors(0.2% vs. 0%, P =0.317) and DFS (95.5% vs. 97.1%, P =0.246) between the ablation and lobectomy groups during the median follow-up of 96.5 months. The ablation group had significantly lower complication rates (0.7% vs. 5.2%, P <0.001), shorter post-treatment hospitalization {median [interquartile range (IQR)], 0 vs. 4.0 [3.0] days, P <0.001}, shorter procedure time [8.5 (2.8) vs. 90.0 (43.8) min, P <0.001], reduced estimated blood loss [0 vs. 20.0 (10.0) ml, P <0.001], and lower cost [$1873.2 (254.0) vs. $2292.9 (797.8), P <0.001] than the lobectomy group.

CONCLUSIONS

This study revealed comparable disease progression and survival outcomes between ablation and lobectomy for solitary PTMC. Imaged-guided thermal ablation could be effective and safe alternatives to lobectomy for properly selected patients with PTMC.

Advances in clinical research on ultrasound-guided radiofrequency ablation for papillary thyroid microcarcinoma

Ultrasound-guided radiofrequency ablation (RFA) emerges as a minimally invasive strategy for papillary thyroid microcarcinoma (PTMC), offering advantages over traditional surgical approaches. RFA employs high-frequency electric currents under precise ultrasound guidance to ablate cancerous tissue. Clinical trials consistently demonstrate RFA's efficacy in tumor control and patient-reported outcomes. However, long-term studies are essential to validate its durability and monitor for potential complications. Collaborative efforts among various medical disciplines ensure procedural accuracy and comprehensive postoperative care. Technological innovations, such as enhanced ultrasound imaging and temperature control, promise to refine RFA's precision and effectiveness. Nevertheless, challenges persist, including the need for standardized protocols and comparative studies with traditional treatments. Future research should focus on long-term outcomes, patient selection criteria, and optimization of procedural techniques to solidify RFA's role in PTMC management. RFA presents a promising avenue for PTMC treatment, warranting further investigation and refinement in clinical practice.

Efficacy and safety of ultrasound-guided percutaneous radiofrequency ablation for synovial hyperplasia

PURPOSE

This study aimed to investigate the efficacy and safety of ultrasound-guided percutaneous radiofrequency ablation (RFA) for the treatment of synovial hyperplasia in the knee joints of antigen-induced arthritis (AIA) model rabbits.

METHODS

Forty Japanese large-eared white rabbits were divided into AIA and control groups. After successful induction of the AIA model, the knee joints were randomly assigned to RFA and non-RFA groups. The RFA group underwent ultrasound-guided RFA to treat synovial hyperplasia in the knee joint. Dynamic observation of various detection indices was conducted to evaluate the safety and effectiveness of the RFA procedure.

RESULTS

Successful synovial ablation was achieved in the RFA group, with no intraoperative or perioperative mortality. Postoperative the circumference of the knee joint reached a peak before decreasing in the third week after surgery. The incidence and diameter of postoperative skin ulcers were not significantly different compared to the non-RFA group (p > .05). Anatomical examination revealed an intact intermuscular fascia around the ablated area in the RFA group. The ablated synovial tissue initially presented as a white mass, which subsequently liquefied into a milky white viscous fluid. Gross articular cartilage was observed, along with liquefied necrosis of the synovium on pathological histology and infiltration of inflammatory cells in the surrounding soft tissue.

CONCLUSION

The experimental results demonstrated that ultrasound-guided RFA of the knee in the treatment of synovial hyperplasia in AIA model animals was both effective and safe.

Brazilian Consensus on the Application of Thermal Ablation for Treatment of Thyroid Nodules: A Task Force Statement by the Brazilian Society of Interventional Radiology and Endovascular Surgery (SOBRICE), Brazilian Society of Head and Neck Surgery (SBCCP), and Brazilian Society of Endocrinology and Metabolism (SBEM)

There is increasing interest in ultrasound-guided ablation treatments for thyroid diseases, including benign and malignant ones. Surgeons, radiologists, and endocrinologists carry out these treatments, and various organizations within these specialties have recently released multiple international consensus statements and clinical practice standards. The aim of the present consensus statement is to provide guidance, cohesion, and standardization of best practices for thermal ablation procedures of thyroid nodules. The statement includes the indications for these procedures, preprocedural evaluations, technical aspects of the procedures, posttreatment care, follow-up, complications, and training recommendations. This document was written by a panel of specialists from the Brazilian Society of Interventional Radiology and Endovascular Surgery (SOBRICE), the Brazilian Society of Head and Neck Surgery (SBCCP), and the Brazilian Society of Endocrinology and Metabolism (SBEM). The statement does not aim to provide criteria for assessing the capability of specialists to perform the procedure. Instead, it aims to promote the standardization of best practices to reduce potential adverse outcomes. Additionally, it strives to enhance the delivery of high-quality care and the widespread adoption of these technologies on a national level. The recommendations collectively serve as a guidebook for applying best practices in thyroid ablation.

Efficacy and safety of ultrasound-guided thermal ablation of graves' disease: a retrospective cohort study

BACKGROUND

Ultrasound-guided thermal ablation (TA) has emerged as a robust therapeutic approach for treating solid tumors in multiple organs, including the thyroid. Yet, its efficacy and safety profile in the management of Graves' Disease (GD) remains to be definitively established.

METHODS

A retrospective study was conducted on 50 GD patients treated with TA between October 2017 and December 2021. Key metrics like thyroid volume, volume reduction rate (VRR), thyroid hormones, and basal metabolic rate (BMR) were evaluated using paired Wilcoxon tests.

RESULTS

The intervention of ultrasound-guided TA yielded a statistically significant diminution in total thyroid volume across all postoperative follow-up intervals-1, 3, 6, and 12 months-relative to pre-intervention baselines (p < 0.001). The median VRR observed at these time points were 17.5%, 26.5%, 34.4%, and 39.8%, respectively. Euthyroid status was corroborated in 96% of patients at the one-year follow-up milestone. Transient tachycardia and dysphonia were observed in three patients, while a solitary case of skin numbness was noted. Crucially, no instances of enduring injury to the recurrent laryngeal nerve (RLN) were documented.

CONCLUSIONS

Our investigation substantiates ultrasound-guided TA as a pragmatic, well-tolerated, and safe therapeutic modality for GD. It effectively improves symptoms of hyperthyroidism, engenders a substantial reduction in thyroid volume, and restores thyroid hormone and BMR to physiological levels. Given its favorable safety profile, enhanced cosmetic outcomes, and minimally invasive nature, ultrasound-guided TA is a compelling alternative to thyroidectomy for GD patients.

Safety and efficacy of microwave ablation for symptomatic benign thyroid nodules in children

OBJECTIVE

To evaluate the efficacy and safety of microwave ablation (MWA) for the treatment of symptomatic benign thyroid nodules in children.

METHODS

A retrospective study of MWA for the treatment of 34 symptomatic benign thyroid nodules in 25 children was conducted. Volume reduction ratio (VRR), technique efficacy, symptom score, cosmetic score, and thyroid function were used to evaluate the efficacy of the technique. The associated complications and side effects were recorded.

RESULTS

The participants were followed for at least 6 months (median 12 months, range 6-48 months). After MWA treatment, the volumes of the targeted nodules decreased gradually (median volume 5.86 mL before MWA and 0.34 mL at the final follow-up assessment), the VRR achieved was up to 85.03% at the final follow-up assessment, and the technical efficacy at this time was 91.2%. The subjective and objective nodule-related symptoms were also ameliorated. The circulating hormone concentrations reflecting thyroid function remained within their normal ranges in all the participants after one month of follow-up. The procedure had no major complications.

CONCLUSIONS

MWA seems to be an effective and safe technique for the treatment of symptomatic benign thyroid nodules in pediatric patients.

CLINICAL RELEVANCE STATEMENT

Microwave ablation is a safe and effective method to treat symptomatic benign thyroid nodules in pediatric patients. This treatment may be selected if the patient or parents are not suitable or refuse to undergo surgery.

KEY POINTS

• Microwave ablation is effective in reducing the volume of benign thyroid nodules and ameliorating nodule-related symptoms in pediatric patients. • Microwave ablation is a safe method in children, with low complications. • Microwave ablation does not affect the circulating thyroid hormone concentrations of children.

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.

Comparison of the Therapeutic Efficacy and Technical Outcomes between Conventional Fixed Electrodes and Adjustable Electrodes in the Radiofrequency Ablation of Benign Thyroid Nodules

OBJECTIVE

This study aimed to compare therapeutic efficacy and technical outcomes between adjustable electrode (AE) and conventional fixed electrode (FE) for radiofrequency ablation (RFA) of benign thyroid nodules.

MATERIALS AND METHODS

Between 2013 and 2021, RFA was performed on histologically proven benign thyroid nodules. For the AE method, AE length ≥ 1 cm with higher power and < 1 cm with lower power were utilized for ablating feeding vessels and nodules, especially those near anatomical structures, respectively. The therapeutic efficacy (volume reduction rate [VRR], complication rate, and regrowth rate) and technical outcomes (total energy delivery, ablated volume/energy, RFA time, and ablated volume/time) of FE and AE were compared. Continuous parameters were compared using a two-sample t-test or Mann-Whitney U test, and categorical parameters were compared using a chi-squared test or Fisher's exact test.

RESULTS

A total of 182 nodules (FE: 92 vs. AE: 90) in 173 patients (mean age ± standard deviation, 47.0 ± 14.7 years; female, 90.8% [157/173]; median follow-up, 726 days [interquartile range, 441-1075 days]) were analyzed. The therapeutic efficacy was comparable, whereas technical outcomes were more favorable for AE. Both electrodes demonstrated comparable overall median VRR (FE: 92.4% vs. AE: 84.9%, P = 0.240) without immediate major complications. Overall regrowth rates were comparable between the two groups (FE: 2.2% [2/90] vs. AE: 1.1% [1/90], P > 0.99). AE demonstrated a shorter median RFA time (FE: 811 vs. AE: 627 seconds, P = 0.009). Both delivered comparable median energy (FE: 42.8 vs. AE: 29.2 kJ, P = 0.069), but AE demonstrated higher median ablated volume/energy and median ablated volume/time (FE: 0.2 vs. AE: 0.3 cc/kJ, P < 0.001; and FE: 0.7 vs. AE: 1.0 cc/min, P < 0.001, respectively).

CONCLUSION

Therapeutic efficacy between FE and AE was comparable. AE demonstrated better technical outcomes than FE in terms of RFA time, ablated volume/energy, and ablated volume/time.

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.

Follow-up strategy of radiofrequency ablation for papillary thyroid microcarcinoma: defining a response-to-ablation system

OBJECTIVE

To define a response-to-ablation system based on dynamic risk stratification proposed by the 2015 American Thyroid Association guidelines for predicting clinical outcomes and guiding follow-up strategies for patients with low-risk papillary thyroid microcarcinoma (PTMC) who underwent radiofrequency ablation (RFA).

METHODS

This retrospective study reviewed patients with low-risk PTMC who underwent RFA between 2014 and 2018. We classified patients into three groups based on their response to therapy at the 1-year follow-up: complete, indeterminate, and incomplete. The primary endpoints were local tumor progression (LTP) and disease-free survival (DFS).

RESULTS

Among the 748 patients (mean age, 43.7 years ± 9.8; 586 women), 4.0% (30/748) had LTP during a median follow-up of 5 years. The response was complete in 80.2% (600/748) of the patients, indeterminate in 18.1% (135/748), and incomplete in 1.7% (13/748). The LTP rate in the final follow-up was 1% (6/600), 8.1% (11/135), and 100% (13/13), respectively. The risk of LTP was significantly different in the incomplete response group (HR, 1825.82; 95% CI: 458.27, 7274.36; p < 0.001) and indeterminate response group (HR, 8.12; 95% CI: 2.99, 22.09; p < 0.001) than in the complete response group. There were significant differences in DFS among groups (p < 0.001). The proportion of variation explained and C-index of the system was high (27.66% and 0.79, respectively).

CONCLUSIONS

We defined a response-to-ablation system that provides a new paradigm for the management of patients with PTMC who underwent RFA. Our data confirm that the system can effectively predict the risk of LTP and guide ongoing follow-up recommendations.

KEY POINTS

• The response-to-ablation system can classify patients with low-risk PTMC who underwent RFA into complete, indeterminate, or incomplete response categories. • Results suggest that, in this population, this system can identify three separate cohorts of patients who have significantly different clinical outcomes. • The response-to-ablation system will help better tailor the ongoing follow-up recommendations.

The Emerging Landscape for Combating Resistance Associated with Energy-Based Therapies via Nanomedicine

Cancer represents a serious disease with significant implications for public health, imposing substantial economic burden and negative societal consequences. Compared to conventional cancer treatments, such as surgery and chemotherapy, energy-based therapies (ET) based on athermal and thermal ablation provide distinct advantages, including minimally invasive procedures and rapid postoperative recovery. Nevertheless, due to the complex pathophysiology of many solid tumors, the therapeutic effectiveness of ET is often limited. Nanotechnology offers unique opportunities by enabling facile material designs, tunable physicochemical properties, and excellent biocompatibility, thereby further augmenting the outcomes of ET. Numerous nanomaterials have demonstrated the ability to overcome intrinsic therapeutic resistance associated with ET, leading to improved antitumor responses. This comprehensive review systematically summarizes the underlying mechanisms of ET-associated resistance (ETR) and highlights representative applications of nanoplatforms used to mitigate ETR. Overall, this review emphasizes the recent advances in the field and presents a detailed account of novel nanomaterial designs in combating ETR, along with efforts aimed at facilitating their clinical translation.

Radiofrequency ablation of thyroid nodules: a clinical review of treatment complications

Radiofrequency ablation (RFA) is a minimally invasive ablative modality for the treatment of thyroid nodules. Reports of RFA use have demonstrated an impressive safety profile and excellent volume reduction rates between 60-90%. Given its increased popularity in the United States as well as globally, numerous recent works have been published and a discussant of relevant complications incorporating recent insight may assist practitioners in minimizing complications and optimizing patient outcomes. Herein, we provide a comprehensive and updated review of the reported complications and side effects following RFA, summarizing their frequency and clinical presentation. We also describe a means of minimizing such complications and/or side effects. Overall, the safety profile of RFA is impressive and superior to that of thyroid surgery. The overall risk of complication is reportedly 2-3%. The risk of permanent complication or severe injury is very unlikely, below 1%. Complications are infrequent, but may be nerve-related, endocrine-related, or iatrogenic-related, and consequences of localized heat delivery. The vast majority of complications related to RFA can be managed conservatively, without need for invasive measures. This review will assist surgeons and clinicians in recognizing and treating the various complications and side effects in clinical practice.

Radiofrequency ablation as a treatment modality for primary hyperparathyroidism: a systematic literature review

Background

Primary hyperparathyroidism (pHPT) is an endocrine disorder typically characterized by elevated serum calcium and elevated parathyroid hormone (PTH). While parathyroidectomy is the standard treatment, non-operative intervention such as radiofrequency ablation (RFA) has been adopted as an alternative for the management of pHPT, as it has been utilized in other endocrine glands such as thyroid and adrenal. In this literature review, we aim to evaluate the current practice of RFA for pHPT.

Methods

A systematic literature search using PubMed, Web of Science, and Embase through June 2022 was conducted. Studies included in the review consisted of patient cohorts who had an unequivocal diagnosis of pHPT and underwent the treatment of pHPT with RFA. When more than one study was published from a similar cohort of patients, only the study with the most number of patients was considered. Studies included were assessed for bias using the critical appraisal instruments from the Joanna Briggs Institute (JBI) System.

Results

A total of 14 studies describing 167 parathyroid glands treated in 163 patients were reviewed. The overall cure rate was 91.2%, with 5 patients undergoing more than one ablation. The most common adverse effect encountered was temporary dysphonia. Incomplete ablation and missed multiglandular disease were the most common reasons for RFA treatment failure.

Conclusions

RFA may be an effective and safe alternative to parathyroidectomy in select patients with a well-localized, well-located parathyroid adenoma. Additional long-term data are needed to refine its role in the pHPT treatment algorithm.

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

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

Long-Term Outcomes and Risk Factors of Radiofrequency Ablation for T1N0M0 Papillary Thyroid Carcinoma

Importance

Radiofrequency ablation (RFA) has gained increasing interest as a minimally invasive procedure to treat low-risk papillary thyroid carcinoma (PTC). Considering the indolent nature of this disease, studies in large populations with long follow-up would be invaluable to further substantiate the effectiveness of RFA.

Objective

To evaluate the long-term (58.5 months) outcomes of patients with T1N0M0 PTC who underwent RFA and investigate risk factors for local tumor progression (LTP).

Design, Setting, and Participants

This cohort study included 1613 patients aged 18 years or older with T1N0M0 PTC who underwent ultrasonography-guided RFA between January 2014 and December 2020 at the Chinese People's Liberation Army General Hospital in Beijing, China. Included in the analysis were patients with PTC (confirmed by biopsy) with a maximum diameter of 20 mm or less; no evidence of extrathyroidal extension (capsular disruption or involvement of perithyroidal tissue), lymph node metastasis, or distant metastasis on ultrasonography or computed tomography; and no evidence of an aggressive subtype of PTC on biopsy. Patients with PTC larger than 2 cm, less than 12 months of follow-up, or inadequate follow-up information were excluded. Data were analyzed in April 2023.

Main Outcomes and Measures

Long-term progression rate, disease-free survival, and complete tumor disappearance and their associations with patient and tumor characteristics. Disease-free survival was calculated using Kaplan-Meier analysis. Cox proportional hazards regression analyses were performed to assess risk factors for LTP and complete tumor disappearance.

Results

The study comprised 1613 patients (mean [SD] age, 43.3 [10.2] years; 1256 women [77.9%]) with 1834 T1N0M0 PTC tumors. During a mean follow-up of 58.5 months (range, 27 to 111 months), LTP was observed in 69 patients (4.3%), including 42 (2.6%) with tumor recurrence and 27 (1.7%) with tumor persistence. Cumulative disease-free survival rates at 1, 3, 5, and 8 years were 98.0%, 96.7%, 96.0%, and 95.7%, respectively. The overall complication rate was 2.0% (32 patients), with 6 (0.4%) major complications. Independent risk factors for LTP included subcapsular tumor location 2 mm or less from the capsule or trachea (hazard ratio [HR], 3.36; 95% CI, 2.02-5.59; P < .001) and multifocal tumors (HR, 2.27; 95% CI, 1.30-3.96; P = .004). Furthermore, 1376 patients (85.3%) showed complete tumor disappearance at follow-up ultrasonographic examination. Factors associated with complete tumor disappearance included age 40 years or less (HR, 0.78; 95% CI, 0.70-0.87; P < .001), stage T1a tumors (HR, 0.37; 95% CI, 0.31-0.45; P < .001), and unifocal tumors (HR, 0.50; 95% CI, 0.42-0.60; P < .001).

Conclusions and Relevance

In this cohort study, ultrasonography-guided RFA for T1N0M0 PTC had excellent long-term outcomes. Patients with unifocal T1N0M0 PTC and subcapsular tumor location more than 2 mm from the capsule or trachea may be the best candidates for RFA.

Bilateral nodule radiofrequency ablation in a single setting: First reported case series

BACKGROUND

Radiofrequency ablation (RFA) is a minimally-invasive ablative technique with an impressive safety profile used to manage thyroid nodules. Current reports with RFA describe the treatment of a single nodule in a single-setting. We describe the first series of bilateral nodule RFA in a single-setting.

METHODS

RFA was performed on patients with bilateral thyroid nodules in a single-setting. A cohort of randomly selected patients undergoing RFA for bilateral thyroid nodules in a separate setting was reported as a control cohort.

RESULTS

A total of 12 patients were included in our series, included 6 patients in the single-setting ablation cohort. For patients with bilateral nodules treated by RFA in a separate setting, the mean volume reduction rate (VRR) at 6 months of 63.79% ± 18.86%. There were no reports of complications in the separate setting cohort. For patients with bilateral nodules treated by RFA in a single-setting, the mean VRR at 6 months was 64.% ± 18.97%. There were no reports of complications in the single-setting cohort.

CONCLUSIONS

Our work describes a novel use of RFA, providing preliminary insight into its use for appropriately selected patients with bilateral thyroid nodules. Future studies with larger sample sizes are warranted to corroborate and expand on our findings.

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.

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

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

[Training of Radiofrequency Ablation for Thyroid Nodules in Korea: Current and Future Perspective]

Radiofrequency ablation (RFA) is a minimally invasive treatment modality used as an alternative to surgery in patients with benign thyroid nodules and recurrent thyroid cancers. In Korea, RFA for thyroid nodules was first performed in 2002, and a large population study was published in 2008. The Task Force Committee of the Korean Society of Thyroid Radiology (KSThR) developed its first recommendations for RFA in 2009, which were revised in 2012 and 2018. The KSThR guideline was the first guideline for RFA of thyroid nodules worldwide and has become a guideline for physicians to perform thyroid RFA in Korea and other countries around the world. These guidelines have contributed significantly to the establishment and widespread use of RFA worldwide. In addition, since 2015, the KSThR has conducted intensive hands-on courses depending on the level of the participants. In this article, the authors introduce the history of eduction for RFA conducted by the KSThR and describe the learning curve of RFA and current training programs in Korea, along with future directions for training programs.

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.

Effect of ultrasound parameters of benign thyroid nodules on radiofrequency ablation efficacy

BACKGROUND AND AIM

Ultrasound-guided radiofrequency ablation (RFA) is a minimally invasive therapy for thyroid nodules (TNs). Understanding the determinants of RFA efficacy can improve treatment and prognosis. This study aims to investigate the relationship between ultrasound parameters of benign TNs and the efficacy of RFA.

METHODS

A pretest-posttest interventional study was conducted in 2021 on 250 randomly sampled patients with benign TNs, receiving RFA. For this purpose, the volume reduction (VR) and the VR ratio (VRR) of the nodules were measured at the 1-, 3-, 6-, and 12-month follow-up periods after the RFA completion. The technical success rate (TSR) of this procedure was then categorized into four states, including low (VRR < 25%), moderate (VRR = 25-49%), high (VRR = 50-74%), and very high (VRR ≥ 75). Ordered logistic regression (OLR) was further utilized to investigate the effect of the ultrasound parameters of TNs on the TSR. The analyses were notably performed using Stata 14.2.

RESULTS

The VRR at the 1-, 3-, 6-, and 12-month follow-up periods were 38.7%, 53.6%, 59.3%, and 59.9%, respectively. The mean VR was also statistically significant at all follow-ups (p < 0.001). At the 1-, 3-, and 6-month follow-up periods, the VR of over 50% was observed in 28.2%, 52.1%, and 65.2% of the nodules, respectively. The odds ratios (ORs) of the RFA success were found to be 4.3 times higher for the nodules in the left lobe compared to the right lobe (OR: 4.31, p = 0.002), 6.3 times greater for isoechoic nodules compared to hyperechoic nodules (OR: 6.39, p < 0.001), 6.2 times higher for hyper-vascular nodules compared to hypo-vascular nodules (OR: 6.25, p = 0.005), and 2.3 times greater for mixed nodules compared to solid ones (OR: 2.37, p = 0.049).

CONCLUSION

The ultrasound parameters of TNs had a statistically significant effect on the efficacy of RFA. Small-sized, isoechoic, and hyper-vascular nodules, as well as those with mixed tissue, were observed to respond better to RFA, leading to a better prognosis in terms of VR after treatment.

Clinical outcomes of ultrasound-guided radiofrequency ablation for solitary T1N0M0 papillary thyroid carcinoma: A retrospective study with more than 5 years of follow-up

BACKGROUND

Ultrasound-guided radiofrequency ablation (RFA) has been used in patients with papillary thyroid carcinoma (PTC) who refuse surgery or active surveillance. However, the long-term outcomes are still limited. This study aimed to evaluate the clinical outcomes of RFA for solitary T1N0M0 PTC in a large cohort over a more than 5-year follow-up period.

METHODS

This retrospective study included 358 patients with solitary T1N0M0 PTC who were treated with RFA and followed for at least 5 years. The bipolar RFA procedure was performed using hydrodissection technique, transisthmic approach, and moving-shot technique. The primary outcomes were disease progression, including lymph node metastasis (LNM), recurrent tumor, persistent tumor, and distant metastasis. The secondary outcomes were volume reduction rate, complete disappearance rate, complications, and delayed surgery.

RESULTS

During a mean follow-up period of 75.5 ± 9.7 months, the overall disease progression was 5.0%. The incidence of LNM, recurrent tumor, and persistent tumor was 1.4%, 3.1%, and 0.6%, respectively. There were no significant differences in the disease progression (5.0% vs. 5.5%, p = 1.000), LNM (1.3% vs. 1.8%, p = .568), recurrent tumor (3.3% vs. 1.8%, p = .872), persistent tumors (0.3% vs. 1.8%, p = .284), and 5-year recurrence-free survival rates (95.4% vs. 96.4%, p = .785) in the T1a and T1b groups. Volume reduction rate was 100.0 ± 0.3%, with 96.9% of tumors disappearing. No complications occurred. No patients underwent delayed surgery because of anxiety.

CONCLUSIONS

RFA is an effective and safe alternative for patients with T1N0M0 PTC and can offer a minimally invasive curative option for patients who refuse surgery or active surveillance.

PLAIN LANGUAGE SUMMARY

During a mean follow-up period of 75.5 ± 9.7 months, the overall papillary thyroid carcinoma disease progression was 5.0%. The volume reduction rate was 100.0 ± 0.3%, with 96.9% of tumors disappearing. The T1a and T1b groups had similar incidence of disease progression and 5-year recurrence-free survival rates. No patients experienced complications or underwent delayed surgery because of anxiety.

Value of CEUS combined with feeding artery ablation in the microwave ablation of large solid benign thyroid nodules

OBJECTIVES

To investigate the value of contrast-enhanced ultrasound (CEUS) combined with feeding artery ablation in the microwave ablation (MWA) of large solid benign thyroid nodules (LSBTNs) with a diameter ≥ 4 cm.

METHODS

We retrospectively analyzed 122 patients with LSBTN ≥ 4 cm in diameter treated with MWA. During evaluations before and after MWA, 53 patients who underwent conventional ultrasound examination were classified as the routine group, and 69 patients who underwent CEUS combined with feeding artery ablation were classified as the union group. The differences in ablation energy required per milliliter (AERPM), complication rate, regrowth rate, and volume reduction rate (VRR) were compared between the two groups.

RESULTS

The AERPM of the union group was significantly less than that of the routine group (956.3 ± 38.5 J/mL vs. 1025.9 ± 121.5 J/mL, p < 0.001). The complication rate of the routine group was significantly higher than that of the union group (13.2% vs. 2.9%, p = 0.031). The regrowth rate of the routine group (22.6%, 12/53) was significantly higher than that of the union group (7.2%, 5/69) (p = 0.015). At the 1st, 3rd, 6th, 12th, 18th, and 24th month after ablation, the mean VRRs of the routine group were significantly less than those of the union group, with p values of < 0.001, < 0.001, 0.002, 0.007, 0.013, and < 0.001, respectively.

CONCLUSIONS

The application of CEUS combined with feeding artery ablation in the MWA of LSBTNs is helpful to reduce the regrowth rate, improve the ablation efficiency, and reduce bleeding.

KEY POINTS

• CEUS combined with feeding artery ablation in MWA of LSBTNs is helpful to reduce regrowth rate. • CEUS combined with feeding artery ablation can help improve ablation efficiency than conventional ultrasound in LSBTNs. • CEUS combined with feeding artery ablation helps reduce the incidence of bleeding during MWA.

Ultrasound imaging in thyroid nodule diagnosis, therapy, and follow-up: Current status and future trends

Ultrasound, the primary imaging modality in thyroid nodule management, suffers from drawbacks including: high inter- and intra-observer variability, limited field-of-view and limited functional imaging. Developments in ultrasound technologies are taking place to overcome these limitations, including three-dimensional-Doppler, -elastography, -nodule characteristics-extraction, and novel machine-learning algorithms. For thyroid ablative treatments and biopsies, perioperative use of three-dimensional ultrasound opens a new field of research. This review provides an overview of the current and future applications of ultrasound, and discusses the potential of new developments and trends that may improve the diagnosis, therapy, and follow-up of thyroid nodules.

Optimal thyrotropin level for low-risk papillary thyroid carcinoma after ultrasound-guided radiofrequency ablation

PURPOSE

Maintaining an optimal thyroid stimulating hormone (TSH) level is important in the postoperative management of papillary thyroid carcinoma (PTC). However, there is little evidence for TSH target levels in patients undergoing radiofrequency ablation (RFA). This study aimed to determine the optimal TSH level for management in low-risk patients who underwent RFA.

METHODS

This retrospective propensity score-matched cohort study included patients with low-risk PTC who underwent RFA from January 2014 to December 2018. The patients were categorized into two groups based on the range of TSH levels: low (≤2 mU/L) and high (>2 mU/L) TSH levels. Local tumor progression and disease-free survival (DFS) were compared between the low TSH and high TSH groups, using propensity score analyses based on patient- and tumor-level characteristics. Univariate analyses were performed to select risk factors for tumor progression.

RESULTS

Overall, our study included 516 patients with low-risk PTC who underwent RFA with a long-term follow-up of 5-years. During follow-up, the overall incidence rate of local tumor progression was 4.8% (25/516), with no significant difference between the matched groups (7/106 [6.6%] vs. 5/53 [9.4%], p = 0.524). DFS did not differ between the two groups (p = 0.5). Moreover, TSH level was not regarded as a significant predictor of tumor progression after Cox analysis; primary tumor size was the only relevant risk factor.

CONCLUSION

This large propensity-matched study revealed no association between TSH levels and tumor progression. Thus, for patients with low-risk PTC who underwent RFA, the optimalTSH level is recommended at the euthyroid range.

Radiofrequency Ablation for Benign Thyroid Nodules: Radiology In Training

Two patients, one with benign nonfunctioning nodules and one with functioning thyroid nodules, both of whom underwent radiofrequency ablation, are presented. Preprocedural evaluation, procedural considerations, and follow-up care of thyroid radiofrequency ablation, as well as published evidence on the topic, are discussed.