Percutaneous laser ablation for benign and malignant thyroid diseases

Chinese guidelines for ultrasound-guided thermal ablation of thyroid nodules (2024 edition)

The Chinese guidelines for ultrasound-guided thermal ablation of thyroid nodules (2024 edition) were jointly initiated by the Ultrasound Committee of Chinese Medical Association, the Interventional Ultrasound Committee of Chinese Association of Ultrasound in Medicine and Engineering, the Ultrasonic Intervention Committee of Chinese Colleges of Interventionalists, and the Oncological Intervention Committee of Chinese Research Hospital Association; 37 multidisciplinary experts in interventional ultrasound, ultrasound medicine, endocrinology, and thyroid surgery participated in the compilation of this guide, which expanded the depth and breadth of the perspective and enhanced the authority of the guide. Based on the systematic review of literature related to ultrasound-guided thermal ablation of thyroid nodules and the professional opinions of experts, the guidelines define the indications and contraindications of thermal ablation, including pre-ablation evaluation and preparation, thermal ablation techniques and operational procedures, post-ablation follow-up, therapeutic effect evaluation, complication prevention and treatment, and the writing of medical documents for ablation. According to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE), a total of 17 objective and comprehensive recommendations were given. The publication and promotion of this guideline will play a positive role in promoting the standardization of ultrasound-guided thermal ablation of thyroid nodules.

Efficacy and safety of microwave ablation for treatment of follicular thyroid neoplasms: a preliminary study

OBJECTIVE

To assess the feasibility, efficacy, and safety of microwave ablation in treating follicular thyroid neoplasms and suspicious follicular thyroid neoplasms.

METHODS

In this retrospective study, the data of patients treated with microwave ablation for follicular neoplasms from December 2016 to January 2024 were summarized. The changes in nodule size, volume, technical success rate, disease progression, complete tumor resolution, thyroid function, and complications post-ablation were evaluated.

RESULTS

Seventy-four patients (15 men, 59 women; mean age 46.3 ± 15.2 years) with follicular neoplasms were included. Over a median follow-up of 13 months, complete ablation was achieved, giving a 100% technical success rate. At the first month post-ablation, the maximum diameter of nodules showed no significant change (p = 0.287). From the third month, both maximum diameter and volume significantly decreased (p < 0.005 for all). Volume reduction rates remained stable at one and three months (p = 0.389 and 0.06, respectively) but increased significantly thereafter (p < 0.005 for all). By 24 months, the median maximum diameter had reduced from 2.3 cm to 0 cm, achieving a median volume reduction rate of 100%. Nodules disappeared completely in 20.3% (15/74). Local recurrence was noted in 2.7% of cases (2/74), with no metastasis or neoplasm-related deaths reported. Thyroid function remained unchanged post-treatment (p > 0.05). The complication and side effect rates were 8.1% and 4.1%, respectively.

CONCLUSIONS

Initial findings suggest microwave ablation is an effective and safe treatment for follicular neoplasms, with low incidences of disease progression and complications, while maintaining thyroid function.

Preclinical assessment of a mathematical model for ablation zone prediction in thyroid laser ablation

To develop and validate a 3D simulation model to calculate laser ablation (LA) zone size and estimate the volume of treated tissue for thyroid applications, a model was developed, taking into account dynamic optical and thermal properties of tissue change. For validation, ten Yorkshire swines were equally divided into two cohorts and underwent thyroid LA at 3 W/1,400 J and 3 W/1,800 J respectively with a 1064-nm multi-source laser (Echolaser X4 with Orblaze™ technology; ElEn SpA, Calenzano, Italy). The dataset was analyzed employing key statistical measures such as mean and standard deviation (SD). Model simulation data were compared with animal gross histology. Experimental data for longitudinal length, width (transverse length), ablation volume and sphericity were 11.0 mm, 10.0 mm, 0.6 mL and 0.91, respectively at 1,400 J and 14.6 mm, 12.4 mm, 1.12 mL and 0.83, respectively at 1,800 J. Gross histology data showed excellent reproducibility of the ablation zone among same laser settings; for both 1,400 J and 1,800 J, the SD of the in vivo parameters was ≤ 0.7 mm, except for width at 1,800 J, for which the SD was 1.1 mm. Simulated data for longitudinal length, width, ablation volume and sphericity were 11.6 mm, 10.0 mm, 0.62 mL and 0.88, respectively at 1,400 J and 14.2 mm, 12.0 mm, 1.06 mL and 0.84, respectively at 1,800 J. Experimental data for ablation volume, sphericity coefficient, and longitudinal and transverse lengths of thermal damaged area showed good agreement with the simulation data. Simulation datasets were successfully incorporated into proprietary planning software (Echolaser Smart Interface, Elesta SpA, Calenzano, Italy) to provide guidance for LA of papillary thyroid microcarcinomas. Our mathematical model showed good predictability of coagulative necrosis when compared with data from in vivo animal experiments.

Effectiveness and Safety of Percutaneous Treatment in Lesions Suggestive of Thyroid Cancer (Bethesda V and VI-T1aN0M0) Compared to Surgical Treatment: Systematic Review and Meta-Analysis

INTRODUCTION

Thyroid nodules are common entities, with 5% malignancy. Differentiated thyroid cancer represents 90% of thyroid malignancies, with papillary carcinoma being the most common. Management is generally surgical; among its complications are injury to the recurrent laryngeal and superior laryngeal nerve, causing hoarseness, postsurgical hypoparathyroidism, hypothyroidism, and pain. Other noninvasive percutaneous interventions of thermal ablation such as microwave, radiofrequency, or laser incur lower costs and could be an option for treatment.

OBJECTIVE

To determine the effectiveness and safety of thermal ablation in lesions suspected of thyroid cancer (Bethesda V and VI/T1aN0M0) compared to surgical treatment.

METHODS

Systematic review/meta-analysis of observational studies and clinical trials. Database search includes MEDLINE/PUBMED, Embase, Scopus, Scielo, and BVS/LILACS. Studies on patients over 18 years of age with lesions suspicious of thyroid cancer were included.

RESULTS

A total of 10 studies were obtained, with 2939 patients: 1468 subjected to thermal ablation and 1471 to surgery. Regarding effectiveness, no differences were found in local recurrence [relative risk (RR) 1.17 (95% CI 0.69-1.99)] and cervical lymph node metastasis [RR 0.76 (95% CI 0.43-1.36)]. Regarding safety, infection [RR 0.29 (95% CI 0.05-1.74)], hematoma [RR 0.57 (95% CI 0.17-1.94)], and transient hoarseness [RR 0.77 (95% CI 0.39-1.51)] were evaluated, without difference. However, permanent hoarseness had significant differences in favor of thermal ablation [RR 0.29 (95% CI 0.11-0.75)].

CONCLUSIONS

Thermal ablation for the treatment of T1aN0M0 papillary thyroid carcinoma is equally effective when compared to surgical techniques and offers a better safety profile, particularly in permanent hoarseness.

Upgraded hydrodissection and its safety enhancement in microwave ablation of papillary thyroid cancer: a comparative study

OBJECTIVES

To study the efficacy and safety of an improved hydrodissection protocol based on the perithyroidal fascial space during microwave ablation for papillary thyroid carcinoma (PTC).

METHODS

The data of 341 patients (94 men and 247 women, median age 41 years old, 25%-75% interquartile range 34-53 years old, nodule maximum diameter 0.2-1.9 cm) who underwent microwave ablation for PTC were retrospectively reviewed. Among them, 185 patients underwent traditional hydrodissection and served as a control group, and 156 patients underwent improved hydrodissection based on perithyroidal fascial spaces, constituting the improved group. Improvements in safety were analyzed by comparing complications between the two groups. The characteristics of hydrodissected spaces, complications, and follow-up results were recorded.

RESULTS

Hydrodissection was successfully performed in all enrolled patients according to the protocol. The incidence of hoarseness caused by recurrent laryngeal nerve injury, the most common complication in thermal ablation of thyroid nodules, was significantly lower in the improved group than in the control group (1.9% vs. 8.1%, p = 0.021). The median hoarseness recovery time in the improved group was shorter than that in the control group (2 months vs. 3 months, p = 0.032). During follow-up, no local recurrence was encountered in either group. The tumor disappearance rate was not significantly different between the two groups (69.9% vs. 75.7%, p = 0.228).

CONCLUSIONS

Improved hydrodissection based on perithyroidal fascial spaces had better protective effects than traditional hydrodissection.

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 for benign thyroid nodule treatment: New solution in our center

INTRODUCTION AND IMPORTANCE

Thyroid nodules are one of the most common thyroid disorders and are estimated at 4-7 % in the general population. Although it is estimated that 95 % of thyroid nodules are benign and only 4.0-6.5 % malignant, a combined assessment of clinical data, ultrasound imaging, and FNAB is needed to estimate the risk of malignancy. Several minimally invasive nonsurgical modalities have been developed to treat thyroid nodules, including ethanol ablation (EA), laser ablation (LA), microwave ablation (MWA), and radiofrequency ablation (RFA). Since 2006, this method had been used to treat thyroid nodules and reported to have good efficacy and safety for treating benign thyroid nodules and recurrent thyroid cancer. This paper aims to provide the efficacy and safety of the RFA procedure in benign thyroid lesions.

CASE PRESENTATIONS

Here we report 34 cases of patients with thyroid nodules who underwent RFA procedures. After the procedure, patients were followed up in the first, third, sixth, and twelfth months. The ratio of decreasing volume in the first, third, sixth, and twelfth months was as follows 81.6 %; 76.89 %; 63.48 %, 60.11 %.

CLINICAL DISCUSSION

Factors that are thought to predict RFA response include small volume nodule (<12 ml), the presence of a fluid component and well-defined margins, the absence of vascularization, and nonfunctioning status. However, RFA has several limitations, including the procedure that is highly operator dependent to maximize its efficacy, the possibility of persistent lesions, and the lack of a final histological diagnosis that does not completely exclude aggressive histological variants.

CONCLUSION

The RFA procedure has minimal side effects, is highly effective, and is short in procedure time.

US-CT fusion-guided percutaneous radiofrequency ablation of large substernal benign thyroid nodules

The aim of the present study was to assess feasibility, safety and outcome of ultrasound (US) guided percutaneous radiofrequency (RF) ablation of large substernal benign thyroid nodules assisted by US-computed tomography (CT) fusion imaging and real-time virtual needle tracking (VT) system. Thirty patients (18 females, mean age 56 y, range 32-76 y) with 35 benign nonfunctioning thyroid nodules (mean volume ± SD 26.8 ± 7.6 mL; range 20-38mL) were selected for CT-US fusion guided RF ablation. Nodules' volume was evaluated before treatment and during 12-months follow-up. Complications' rate was also evaluated. US-CT fusion imaging with VT system was feasible in all cases (feasibility 100%) and it was always possible to complete the procedure as planned (technical success 100%). Minor complications occurred in 2/30 cases (6.6%). No major complications occurred. 50% volume reduction (technique efficacy) was achieved in 93% cases, with a significant mean volume reduction at 12 months follow-up (68.7 ± 10.8%), (p < .001). The VT system could be useful in thyroid nodules ablation procedures assistance being able to track the RF electrode tip even when this is obscured by the bubbles produced by the ablative process. The combination of fusion imaging with VT assisted RF ablation represents a safe, non-surgical treatment option for patients with large substernal benign thyroid nodules.

Ultrasound-guided thermal ablation for hyperparathyroidism: current status and prospects

BACKGROUND

Hyperparathyroidism (HPT) is classified into primary HPT (PHPT), secondary HPT (SHPT), tertiary HPT (THPT), and pseudohyperparathyroidism. Parathyroid surgery is generally reserved for patients with symptomatic PHPT and asymptomatic patients who meet the surgical guideline criteria. However, the risk of complications and mortality after parathyroid gland surgery increases with increasing patient age.

AIM

This study aimed to review existing research on laser ablation, radiofrequency ablation, microwave ablation, and high-intensity focused ultrasound in the treatment of HPT and analyze its application prospects.

CONCLUSIONS

Thermal ablation is a good alternative treatment for patients with parathyroid hyperplasia who do not meet the criteria or decline surgery. Being a type of minimally invasive treatment, ultrasound-guided thermal ablation has the advantages of easy operation, rapid recovery, and reusability and is used widely.

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.

Thermal ablation for papillary thyroid microcarcinoma located in the isthmus: a study with 3 years of follow-up

Aims: To analyze the outcomes of thermal ablation for isthmic papillary thyroid microcarcinoma (PTMC). Patients & methods: Data for 21 isthmic-PTMC patients who underwent microwave ablation under ultrasound guidance were retrospectively collected. General information on patients and characteristics of tumors were collected. The technical effectiveness, tumor recurrence and volume changes and postoperative complications were recorded during the follow-up. Comparisons with 105 nonisthmic-PTMCs were done. Results: The technical effectiveness was 100%. No recurrence or lymph node metastases were detected. Tumor volume decreased significantly with a volume reduction rate of 1.00 ± 0.01 (range: 0.99 to 1.0) at the final evaluation and seven cases (31.8%) were completely resolved. No complication was encountered. No statistical differences were observed in terms of complications, recurrence or the volume reduction rate compared with the nonisthmic group (all p > 0.05). Conclusions: Percutaneous microwave ablation is an effective treatment strategy for isthmic-PTMC.

2022 Expert consensus on the use of laser ablation for papillary thyroid microcarcinoma

OBJECTIVE

With the aim of standardizing and improving the use of ultrasound-guided PLA on PTMC, a panel of experts from China and Italy, jointly issued this expert consensus on the clinical use of PLA for low-risk PTMC.

METHODS

This expert consensus was developed by Chinese and Italian experts who have specific competence and expertise in this area. An evidence-based approach combining the knowledge and practical experience of the panelists was utilized.

RESULTS

Twenty-six expert consensus recommendations were developed, spanning topics including the indications and contraindications of PLA for PTMC, physician training, preoperative preparation of patients, intraoperative technical procedures, possible complications, efficacy assessment, follow-up strategy, the approach to new PTMC and metastatic lymph nodes after treatment, thyroid-stimulating hormone inhibition therapy, and quality control of the entire procedure.

CONCLUSION

We summarized practical recommendations about standardized and improved PLA treatment for PTMC.

Over than three-year follow-up results of thermal ablation for papillary thyroid carcinoma: A systematic review and meta-analysis

BACKGROUND

This study is a meta-analysis based on evidence-based medicine to explore the long-term (≥3 years) efficacy of thermal ablation in the treatment of papillary thyroid carcinoma (PTC).

METHODS

We searched the PubMed, Embase, and Cochrane Library databases for studies published during the time between the establishment of the databases through June 2022. We included 13 non-randomized-controlled trials (non-RCTs) that reported the application of ultrasound-guided thermal ablation in PTC. We excluded studies that were repeated publications, research without full text, contained incomplete information, lacked data extraction, involved animal experiments, reviews, and systematic reviews. STATA 15.1 software was used to analyze the data.

RESULTS

Tumor volume after thermal ablation at 3-year follow-up was significantly lower than pre-ablation (standardized mean difference [SMD] = -1.06, 95% CI: -1.32~-0.80). The pooled results indicated that the maximum diameter after thermal ablation at 3-year follow-up was significantly lower than pre-ablation (SMD = -1.93, 95% CI: -12.13~-1.73). The pooled results indicated that volume reduction rate (VRR) after thermal ablation at 3-year follow-up was 98.91% (95% CI: 97.98-99.83%), and complete disappearance rate (CDR) after thermal ablation at 3-year follow-up was 83% (95% CI: 67-94%). In addition, the incidence of newly discovered mPTC and lymph node metastases after thermal ablation was 0.3% (95% CI: 0.0-1.0%) and 0.0% (95% CI: 0.0-0.0%), respectively.

CONCLUSION

Overall, the long-term (≥3 years) efficacy of ultrasound-guided thermal ablation in the treatment of PTC was significant, with favorable disease progression. Ultrasound-guided thermal ablation can be considered an alternative approach for patients with PTC who refuse surgery or are unable to undergo surgery.

Ultrasound-Guided Percutaneous Laser Ablation of the Thyroid Gland in a Swine Model: Comparison of Ablation Parameters and Ablation Zone Dimensions

BACKGROUND

To compare laser ablation (LA) zone dimensions at two predetermined energy parameters to cover a theoretical 10 mm zone + 2 mm margin in a thyroid swine model.

METHODS

Approval of the Institutional Animal Care and Use Committee was obtained. After hydrodissection, an ultrasound-guided LA (Elesta Echolaser X4 with Orblaze technology, 1064 nm) was performed in the periphery of the thyroid in 10 swine. Two cohorts were established to ablate a region of 10mm diameter with 2mm margin based on manufacturer's ex vivo data (n= 5 at 3W/1400J and n= 5 at 3W/1800J). The ablation zone was measured on contrast-enhanced computed tomography (CT) and compared to the pathological specimen. Euthanasia was performed 48 hours following ablation.

RESULTS

All ablations in the 3W/1800J group achieved a diameter of 12 mm ± 1 mm in three dimensions. In the 3W/1400J group, 1 ablation reached 12 mm ± 1 mm in 2 dimensions and 4 ablations reached this size in one dimension. Maximum diameter was higher in the 3W/1800J compared to the 3W/1400J group, both on histology (1.46 cm ± 0.05 vs. 1.1 cm ± 0.0, p< 0.01) and CT (1.52 cm ± 0.04 vs. 1.18 cm ± 0.04, p< 0.01). Similar results were obtained regarding volumes, both on histology (1.12 mL ± 0.13 vs. 0.57 mL ± 0.06, p< 0.01) and CT (1.24 mL ± 0.13 vs. 0.59 mL ± 0.07, p< 0.01). Histology showed coagulation necrosis and correlated well with CT measurements.

CONCLUSION

Optimal parameters to obtain a LA zone of 10 mm with 2 mm margin utilizing a single needle are 3W/1800J.

Ultrasound-guided thermal ablation for cervical lymph node metastasis from thyroid carcinoma: a meta-analysis of clinical efficacy and safety

To evaluate the efficacy and safety of thermal ablation (radiofrequency, microwave, and laser) for treating lymph node metastasis from papillary thyroid carcinoma. A literature search was performed in the Medline, Embase, and Cochrane Library databases. Thirteen studies focusing on the efficacy and safety of thermal ablation for treating lymph node metastasis were eligible. The assessed outcomes were primarily pooled using a random- or fixed-effects model based on the results of the heterogeneity test. A total of 235 patients with 445 metastatic lymph nodes were included. Laser, microwave, and radiofrequency ablation all showed a significant reduction in maximum diameter and volume of metastatic lymph nodes (P < 0.0001). Microwave ablation had a higher volume reduction rate (99%; 95% CI, 98-100%) comparing to the other two techniques (P = 0.0057). For all ablations, the pooled completely disappear rate was 70% (95% CI, 45-87%) and the recurrent rate was 3% (95% CI, 2-5%). Thyroglobulin levels significantly decreased (P < 0.0001). No major complications were encountered; the pooled proportion of voice change was low to 4% (95% CI, 2-7%). Thermal ablation is acceptable treatments to manage lymph nodes metastasis from papillary thyroid carcinoma in terms of efficacy and safety for non-surgical candidates.

Comparison of Thermal Ablation and Surgery for Low-Risk Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-Analysis

Objective

Although thermal ablation is effective in treating low-risk papillary thyroid microcarcinomas (PTMCs), comparison of treatment outcomes between thermal ablation and surgery has not yet been systematically evaluated. This study aimed to compare the efficacy and safety of thermal ablation and surgery for the treatment of low-risk PTMCs.

Materials and Methods

Ovid-MEDLINE and EMBASE databases were searched for studies reporting comparisons of treatment results between thermal ablation and surgery for patients with low-risk PTMC published up to April 6, 2020. The analysis evaluated the efficacy (local tumor recurrence, occurrence of new tumor, metastasis, and rescue surgery) and safety (complication rate) of thermal ablation and surgery.

Results

This systematic review included four studies with a total of 339 PTMCs in 339 patients who underwent thermal ablation and 320 PTMCs in 314 patients who underwent surgery. There was no local tumor recurrence or distant metastasis in either group. There was no significant difference in the pooled proportion of lymph node metastasis (2.6% with thermal ablation vs. 3.3% with surgery, p = 0.65), occurrence of new tumors (1.4% with thermal ablation vs. 1.3% with surgery, p = 0.85), or rescue surgery (2.6% with thermal ablation vs. 1.6% with surgery, p = 0.62). However, the pooled complication rate was significantly higher in the surgery group than in the ablation group (3.3% with thermal ablation vs. 7.8% with surgery, p = 0.03).

Conclusion

Both thermal ablation and surgery are effective and safe options for the management of low-risk PTMCs, with thermal ablation achieving a lower complication rate. Therefore, thermal ablation may be considered as an alternative treatment option for low-risk PTMC in patients who refuse surgery and active surveillance or are ineligible for surgery.

Radiofrequency ablation for treatment of thyroid follicular neoplasm with low SUV in PET/CT study

OBJECTIVES

To evaluate the feasibility of radiofrequency ablation (RFA) on follicular neoplasm with low standard uptake value (SUV) in a Positron emission tomography (PET/CT) study.

METHODS

From January 2018 to July 2019, 86 consecutive patients were diagnosed with follicular neoplasm. Of the patients, 28 with PET/CT scans were enrolled in this study. All patients received ultrasound, fine/core needle aspiration, and PET/CT scan prior to treatment. In accordance with previous studies, we recommended 6 patients who had follicular neoplasm with SUVmax ≥5 undergo surgical resection due to an elevated suspicion of malignancy. For 22 patients SUVmax <5, RFA was performed using the moving shot technique. Ultrasound was performed 6 to 12 months after each procedure.

RESULTS

Statistically significant volume reductions during follow-up between values prior to RFA and 12 months post RFA were demonstrated (12.6 ± 20.9 vs. 2.4 ± 3.0 cm³, p < 0.001). Volume reduction ratios at 6-12 months (mean: 10.1 months) after RFA were 73.3% ± 17.7%. One patient presented with vocal cord palsy and recovered within 3 months after RFA. No postprocedural hypothyroidism occurred in the RFA patients.

CONCLUSIONS

By using PET/CT, we can select patients with low SUV follicular neoplasm. RFA offers a safe and feasible alternative treatment option for patients unsuitable or unwilling to undergo surgery.KEY POINTSBy using positron emission tomography-computed tomography, we can distinguish low SUV follicular neoplasm for radiofrequency ablation.For low SUV follicular neoplasm, RF ablation offers a safe and effective alternative treatment option for patients unsuitable or unwilling to undergo surgery.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Radiofrequency Ablation 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.

European Thyroid Association and Cardiovascular and Interventional Radiological Society of Europe 2021 Clinical Practice Guideline for the Use of Minimally Invasive Treatments in Malignant Thyroid Lesions

The growing detection of papillary thyroid microcarcinomas (PTMCs) is paralleled by an increase in surgical procedures. Due to the frequent indolent nature, cost, and risk of surgery, active surveillance (AS) and ultrasound-guided minimally invasive treatments (MITs) are in suitable cases of incidental PTMC proposed as alternatives to thyroidectomy. Surgery and radioiodine are the established treatments for relapsing cervical differentiated thyroid carcinoma (DTC) metastases. But radioiodine refractoriness, risk of surgical complications, adverse influence on quality of life, or declining repeat surgery have led to AS and MIT being considered as alternatives for slow-growing DTC nodal metastases. Also, for distant radioiodine-refractory metastases not amenable to surgery, MIT is proposed as part of a multimodality therapeutic approach. The European Thyroid Association and the Cardiovascular and Interventional Radiological Society of Europe commissioned these guidelines for the appropriate use of MIT. Based on a systematic PubMed search, an evidence-based approach was applied, and both knowledge and practical experience of the panelists were incorporated to develop the manuscript and the specific recommendations. We recommend that when weighing between surgery, radioiodine, AS, or MIT for DTC, a multidisciplinary team including members with expertise in interventional radiology assess the demographic, clinical, histological, and imaging characteristics for appropriate selection of patients eligible for MIT. Consider TA in low-risk PTMC patients who are at surgical risk, have short life expectancy, relevant comorbidities, or are unwilling to undergo surgery or AS. As laser ablation, radiofrequency ablation, and microwave ablation are similarly safe and effective thermal ablation (TA) techniques, the choice should be based on the specific competences and resources of the centers. Use of ethanol ablation and high-intensity focused ultrasound is not recommended for PTMC treatment. Consider MIT as an alternative to surgical neck dissection in patients with radioiodine refractory cervical recurrences who are at surgical risk or decline further surgery. Factors that favor MIT are previous neck dissection, presence of surgical complications, small size metastases, and <4 involved latero-cervical lymph nodes. Consider TA among treatment options in patients with unresectable oligometastatic or oligoprogressive distant metastases to achieve local tumor control or pain palliation. Consider TA, in combination with bone consolidation and external beam radiation therapy, as a treatment option for painful bone metastases not amenable to other established treatments.

Efficacy and safety of microwave ablation for cervical metastatic lymph nodes arising post resection of papillary thyroid carcinoma: a retrospective study

Purpose: To evaluate the efficacy and safety of microwave ablation (MWA) for cervical metastatic lymph nodes (LNs) post resection of papillary thyroid cancer (PTC).Materials and methods: From November 2015 to November 2018, 14 patients with 38 cervical metastatic LNs treated by MWA were included in this retrospective study. Wilcoxon signed rank test was used to compare the changes of LN and serum thyroglobulin levels pre- and post-ablation.Results: The technical success rate in this study was 100% (38/38). The mean follow-up time was 23.6 ± 9.3 months. On pre-ablation contrast-enhanced ultrasound, 25 LNs showed high-enhancement, 8 LNs showed iso-enhancement, and 5 LNs showed low-enhancement. The median largest diameter of LNs at pre-ablation and 3, 6, 9, 12, 18, 24, and 36 months post-ablation was 11.5 mm and 9.5, 9.0, 8.0, 8.0, 8.0, 7.0, and 6.0 mm, respectively. The median volume of LNs at pre-ablation and 3, 6, 9, 12, 18, 24, and 36 months post-ablation were 251.2 mm³ and 206.7, 167.2, 166.2, 155.7, 153.9, 153.9, and 113.1 mm³, respectively. The largest diameter and the volume of the cervical metastatic LNs at the last post-ablation was significantly smaller than the pre-ablation level (p = .0016; p = .0018). Serum Tg level at the last post-ablation (median 1.25 ng/mL) was significantly lower than the pre-ablation level (median 8.35 ng/mL) (p = .001). There were no complications.Conclusion: MWA is a safe and effective novel treatment option for cervical metastatic LN that emerge post resection of PTC.

Neural monitoring during ultrasound-guided radiofrequency ablation of thyroid nodules

BACKGROUND

Intraoperative neurological monitoring is important in locating and assessing nerves during surgery. This study aimed to investigate the feasibility of neural monitoring during ultrasound-guided radiofrequency ablation (RFA) of thyroid nodules.

METHODS

From February 2019 to August 2019, 16 patients (age, 42.8 ± 15.9 years; range, 17-74 years) with benign thyroid nodules who underwent ultrasound-guided RFA with neural monitoring in Zhongshan Hospital, Xiamen University, were included. A neuromonitoring system stimulated the vagus nerve to obtain electromyographic (EMG) signals and predict the function of recurrent laryngeal nerves (RLNs) during RFA. The hydrodissection technique was used to protect the RLN area. Thyroid nodules were treated with the moving-shot technique. The EMG signal value results were recorded and analyzed. All patients underwent laryngoscopic investigation 1 day after the procedure.

RESULTS

Twenty vagus nerves were stimulated preprocedure and postprocedure, and the EMG signals were successfully recorded (100%). The mean initial (before ablation) and final (final ablation) vagus nerve amplitudes were 612.7 ± 130.4 μV (range, 455-882 μV) and 592.7 ± 127.3 μV (range, 410-817 μV), respectively. Based on the EMG signals, all 20 RLNs were judged to be in good condition, consistent with the postprocedure laryngoscopic results. The maximum lesion size and volume at 6 months after RFA were significantly lesser than those at baseline (p < 0.05). The volume reduction rate was 68.5% ± 21.5% (range, 13.0-97.3%). Cosmetic and symptom scores were significantly lower than those at baseline. No complications from neural monitoring occurred.

CONCLUSIONS

Neural monitoring during ultrasound-guided RFA of thyroid nodules is feasible to predict RLN function.

Thermal Ablation of Benign Thyroid Nodules and Papillary Thyroid Microcarcinoma

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

Ultrasound-guided radiofrequency ablation for papillary thyroid microcarcinoma: a retrospective analysis of 198 patients

Purpose: To evaluate the safety and efficacy of ultrasound-guided RFA for the treatment of papillary thyroid microcarcinoma (PTMC).Materials and methods: The data of 204 nodules from 198 PTMC patients who were treated using RFA were retrospectively reviewed in this study. Demographic variables, complication details and CEUS results in different time points were collected. The volumes and volume reduction rate (VRR) of the ablated area under CEUS at different follow-up time points were calculated and compared.Results: All the patients were successfully treated without major complication. Mild complications included cervical discomfort in three cases, postoperative cervical pain in one case, and transient hoarse voice in five cases. The volume of the ablated area in the 1st, 3rd, 6th, 12th, 18th and 24th month postoperatively were 241.7 ± 298.3mm³, 89.8 ± 147.2 mm³, 37.6 ± 87.2 mm³, 13.6 ± 59.8 mm³, 2.4 ± 14.4 mm³, and 0.2 ± 2.0 mm³ respectively, with a statistically significant decrease (F = 138.1, p = .000), and the VRR in those time points were 73.9 ± 13.7%, 90.5 ± 8.2%, 96.1 ± 5.9%, 98.8 ± 3.2%, 99.6 ± 1.9% and 99.8 ± 1.0% respectively, with a statistically significant decrease (F = 695.3, p = .000).Conclusions: US-guided RFA is safe and effective for PTMC, with a good oncological outcome and VRR. Further randomized controlled prospective trials are still needed to compare the value of RFA and surgery.

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.

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.

Clinical practice guidelines for radiofrequency ablation of benign thyroid nodules: a systematic review

Purpose

Thermal ablation is a novel treatment alternative for benign thyroid nodules, and one of the most promising thermal ablation techniques is radiofrequency ablation (RFA). Considering the increasing use of thyroid RFA, some scientific societies have proposed clinical practice guidelines. We systemically reviewed and compared these guidelines for thyroid RFA to identify a standard treatment strategy that represents the positions of most societies.

Methods

We searched the MEDLINE and EMBASE databases for studies with human participants that were published in English between January 1, 2000 and August 2, 2019. Studies containing clinical practice guidelines for the RFA of benign thyroid nodules were included. We extracted data regarding indications, pre- and post-procedural evaluations, treatment techniques, and the need to obtain informed consent.

Results

Of the 83 studies found, four studies were included, and one study was added after searching the bibliographies of those articles. The five included studies were guidelines developed by the Korean Society of Thyroid Radiology, a group of experts from Italian scientific societies, the Italian Working Group on Minimally Invasive Treatments of the Thyroid, the United Kingdom’s National Institute for Health and Clinical Excellence, and a group of four professional Austrian thyroid associations. Indications, pre- and post-procedural evaluations, and techniques were similar across studies; however, differences in each of these categories were found.

Conclusion

While the reviewed guidelines are similar with regard to major categories, international guidelines for the RFA of benign thyroid nodules should be established in the future.

Laser Ablation Versus Radiofrequency Ablation for Benign Non-Functioning Thyroid Nodules: Six-Month Results of a Randomized, Parallel, Open-Label, Trial (LARA Trial)

Background: No direct prospective studies comparing laser ablation (LA) and radiofrequency ablation (RFA) for debulking benign non-functioning thyroid nodules (BNTNs) exist. We aimed at comparing the efficacy and safety of both techniques in patients with solid or predominantly solid BNTN. Methods: This six-month, single-use, randomized, open-label, parallel trial compared the following primary endpoints between the RFA and LA groups six months after treatment: (i) nodule volume reduction expressed as a percentage of nodule volume at baseline; (ii) proportion of nodules with more than 50% reduction (successful rate). We enrolled subjects with a solitary BNTN or dominant nodule characterized by pressure symptoms/cosmetic problems or patients without symptoms who experienced a volume increase >20% in one year. Nodules underwent core needle biopsy for diagnosis. Patients were randomly assigned (1:1) to receive LA or RFA. Safety was assessed in all randomly assigned participants. Results: Sixty patients were randomly assigned to receive either RFA or LA (1:1) between January 2016 and November 2018. Both groups were similar in basal nodule volume, thyroid function, histology, symptoms/cosmetic score, and procedure time. At six months, the nodule volume reduction was 64.3% (95% confidence interval, CI 57.5-71.2) in the RFA group and 53.2% ([CI 47.2-95.2]; p = 0.02) in the LA group. This effect was also confirmed in the linear regression model adjusted for age, baseline volume, and proportion of cellular component (LA vs. RFA percent change Delta = -12.8, p = 0.02). No significant difference was observed in success rate six months after treatment (RFA vs. LA: 86.7% vs. 66.7%, p = 0.13) or in thyrotropin level between the groups. Although improved, no significant difference was observed between RFA and LA for compressive symptoms (RFA: 2.13 vs. 3.9, p < 0 · 001; LA: 2.4 vs. 3.87, p < 0.001) and cosmetic score (RFA: 1.65 vs. 2.2, p < 0.001; LA: 1.85 vs. 2.2, p < 0.001). The adverse event rates (local pain, dysphonia, thyrotoxicosis, fever, hematoma) were 37% (n = 11) and 43% (n = 13) for RFA and LA, respectively, with no requirement for hospitalization. Conclusion: Although the success rate was similar in the RFA and LA groups, RFA achieved a significantly larger nodule volume reduction at six months.

Laser and radiofrequency ablations for benign and malignant thyroid tumors

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

Reproducibility of Ablated Volume Measurement Is Higher with Contrast-Enhanced Ultrasound than with B-Mode Ultrasound after Benign Thyroid Nodule Radiofrequency Ablation-A Preliminary Study

The reproducibility of contrast-enhanced ultrasound (CEUS) and standard B-mode ultrasound in the assessment of radiofrequency-ablated volume of benign thyroid nodules was compared. A preliminary study was conducted on consecutive patients who underwent radiofrequency ablation (RFA) of benign thyroid nodules between 2014 and 2016, with available CEUS and B-mode post-ablation checks. CEUS and B-mode images were retrospectively evaluated by two radiologists to assess inter- and intra-observer agreement in the assessment of ablated volume (Bland–Altman test). For CEUS, the mean inter-observer difference (95% limits of agreement) was 0.219 mL (-0.372–0.809 mL); for B-mode, the mean difference was 0.880 mL (-1.655–3.414 mL). Reproducibility was significantly higher for CEUS (85%) than for B-mode (27%). Mean intra-observer differences (95% limits of agreement) were 0.013 mL (0.803–4.097 mL) for Reader 1 and 0.031 mL (0.763–3.931 mL) for Reader 2 using CEUS, while they were 0.567 mL (-2.180–4.317 mL, Reader 1) and 0.759 mL (-2.584–4.290 mL, Reader 2) for B-mode. Intra-observer reproducibility was significantly higher for CEUS (96% and 95%, for the two readers) than for B-mode (21% and 23%). In conclusion, CEUS had higher reproducibility and inter- and intra-observer agreement compared to conventional B-mode in the assessment of radiofrequency-ablated volume of benign thyroid nodules.

Low-risk papillary thyroid microcarcinoma: Optimal management toward a more conservative approach

The incidence of papillary thyroid microcarcinoma (microPTC) has dramatically increased in the last decades. Most of these tumors remain small and clinically "silent", only small number progress. Although thyroid surgery used to be the only therapeutic approach, recent guidelines now consider active surveillance for low-risk microPTC. For this reason, more accurate risk stratification of microPTC is needed. The optimal management of low-risk microPTC through accurate risk stratification represents a major clinical issue.

US-guided laser treatment of parathyroid adenomas

Objective: To determine the clinical efficacy of laser ablation for the tredatment of primary hyperparathyroidism (pHPT).Materials and methods: Twelve patients with pHPT were treated with laser ablation. Energy was administered by means of 1.5 m optical fibers percutaneously placed into the target via 21 G needles. A laser ablation unit (EchoLaser X4, Esaote) applied 3 W power for 400-600 s/fiber/insertion to a total 3600-9000 Joules of energy. Patient serum parathyroid hormone (PTH) and calcium levels were checked at baseline and thereafter every 6 months. Patients were followed-up for 2 years with serologic and contrast-enhanced ultrasound. Therapeutic success was defined as normal PTH and calcium levels together with disappearance of nodule-related symptoms.Results: All procedures were performed in single session. Immediately following ablation, contrast enhanced ultrasound confirmed that all but one target had become avascular (technical success rate 11/12; 92%), remaining avascular at all follow-up ultrasound examinations, thereafter. The mean volume of parathyroid nodules decreased from 0.54 cc to 0.36 cc (72.0%). Serum PTH and calcium levels were significantly lower at 1, 12 and 24 m compared to baseline (p < 0.01). By 6 m, PTH and calcium returned to normal and were stable until 24 m in all successfully treated patients. All cases of hyperparathyroid-related symptoms resolved by 6 m (ostealgia [n = 5], repeated renal colic [n = 5], vomiting [n = 3]). Only one patient (8%) reported transient dysphonia as a minor complication.Conclusion: Laser ablation of enlarged, symptomatic parathyroid glands is safe and well-tolerated and can produce long-term, sustained reduction of serum PTH and calcium levels.

Effectiveness evaluation of computer-aided diagnosis system for the diagnosis of thyroid nodules on ultrasound: A systematic review and meta-analysis

BACKGROUND

More and more automated efficient ultrasound image analysis techniques, such as ultrasound-based computer-aided diagnosis system (CAD), were developed to obtain accurate, reproducible, and more objective diagnosis results for thyroid nodules. So far, whether the diagnostic performance of existing CAD systems can reach the diagnostic level of experienced radiologists is still controversial. The aim of the meta-analysis was to evaluate the accuracy of CAD for thyroid nodules' diagnosis by reviewing current literatures and summarizing the research status.

METHODS

A detailed literature search on PubMed, Embase, and Cochrane Libraries for articles published until December 2018 was carried out. The diagnostic performances of CAD systems vs radiologist were evaluated by meta-analysis. We determined the sensitivity and the specificity across studies, calculated positive and negative likelihood ratios and constructed summary receiver-operating characteristic (SROC) curves. Meta-analysis of studies was performed using a mixed-effect, hierarchical logistic regression model.

RESULTS

Five studies with 536 patients and 723 thyroid nodules were included in this meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio (DOR) for CAD system were 0.87 (95% confidence interval [CI], 0.73-0.94), 0.79 (95% CI 0.63-0.89), 4.1 (95% CI 2.5-6.9), 0.17 (95% CI 0.09-0.32), and 25 (95% CI 15-42), respectively. The SROC curve indicated that the area under the curve was 0.90 (95% CI 0.87-0.92). The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and DOR for experienced radiologists were 0.82 (95% CI 0.69-0.91), 0.83 (95% CI 0.76-0.89), 4.9 (95% CI 3.4-7.0), 0.22 (95% CI 0.12-0.38), and 23 (95% CI 11-46), respectively. The SROC curve indicated that the area under the curve was 0.96 (95% CI 0.94-0.97).

CONCLUSION

The sensitivity of the CAD system in the diagnosis of thyroid nodules was similar to that of experienced radiologists. However, the CAD system had lower specificity and DOR than experienced radiologists. The CAD system may play the potential role as a decision-making assistant alongside radiologists in the thyroid nodules' diagnosis. Future technical improvements would be helpful to increase the accuracy as well as diagnostic efficiency.