Efficacy and Safety of Thermal Ablation Techniques for the Treatment of Primary Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-Analysis

Early efficacy of radiofrequency ablation for multifocal T1N0M0 papillary thyroid carcinoma: a multicenter study

OBJECTIVES

This study aimed to assess the efficacy and safety of radiofrequency ablation (RFA) for multifocal papillary thyroid carcinoma (M-PTC) and compare these outcomes with those for unifocal papillary thyroid carcinoma (U-PTC).

METHODS

This retrospective multicenter study included 465 patients (367 women and 98 men) who underwent RFA for either U-PTC (411 patients) or M-PTC (54 patients) between May 2015 and October 2022. Patients were followed up at 1, 3, 6, and 12 months post-RFA, then every 6 months in the second year, and annually thereafter. After 1:1 propensity score matching (PSM), local tumor progression rate (LTP), tumor volume, volume reduction rate (VRR), tumor complete response rate (CDR), and complications were evaluated and compared between the M-PTC and U-PTC groups during the follow-up period.

RESULTS

The median follow-up time was 23 months. The median follow-up time for the U-PTC and M-PTC groups was 23 months and 23.5 months, respectively. The overall local tumor progression rate was 0.9% (4/465), and the overall complication rate was 0.6% (3/465). After PSM, no significant differences were observed between the U-PTC and M-PTC groups regarding tumor volume (p = 0.377), VRR (p = 0.151), CDR (50% vs. 44.2%, p = 0.556), or LTP (1.9% vs. 0%, p = 0.556). Additionally, the complication rates were not significantly different between the groups (1.03% vs. 2.5%, p = 0.343).

CONCLUSION

After adequate preoperative evaluation, RFA is an effective and safe treatment for appropriately selected patients with M-PTC, with a prognosis similar to that of U-PTC.

Beyond thermal protection: Injectable self-healing chitosan hydrogel in liver tumor thermal ablation

Thermal ablation technology is crucial for treating early-stage primary tumors. However, the "water isolation" during clinical surgery is limited by unstable thermal protection caused by fluid loss. More seriously, it is prone to intraoperative bleeding, cancer cell metastasis, and postoperative tissue adhesion. Here we introduce a "one stone, four birds" strategy, which utilizes a self-healing chitosan hydrogel without drug assistance to offer four abilities, including thermal protection, hemostasis, anti-tumor metastasis and anti-tissue adhesion. A rabbit VX2 liver transplantation tumor model is established. The self-healing chitosan hydrogel, crosslink of hydroxyethyl chitosan (HC) and dual aldehyde-PEG (Ald-PEG-Ald) using dynamic Schiff base, adheres to the liver surface and remains in situ upon minimally invasive injection, resulting in outstanding thermal protection compared with saline. The temperature of the isolated tissue near the ablation foci remains below 42 °C. Moreover, the self-healing property of the hydrogel can prevent cell leakage during the procedure, thus avoiding intraoperative bleeding, tumor metastasis and postoperative abdominal adhesion. Therefore, this work identified four efficacies of the self-healing chitosan hydrogel in thermal ablation of metastatic liver tumors, providing an advanced alternative for clinical application.

Thyroid cancer

In recent decades, the diagnosis of thyroid cancer, especially the papillary type, has increased significantly due to the use of imaging techniques such as ultrasound. For this reason, it is essential to rationalize diagnosis and treatment, since the behavior of thyroid cancer varies from slow-progressing tumors to highly aggressive ones. The application of risk assessment systems for ultrasound images and the optimization of cytology incorporating molecular studies allows cases to be stratified in order to select therapy on an individual basis. Currently, attempts are being made to avoid overtreatment in low-risk tumors, with active surveillance or minimally invasive techniques. The administration of radioiodine is indicated according to risk, with lower doses, and in advanced cases, oncospecific systemic treatments are being incorporated. The management of thyroid cancer requires a multidisciplinary team and population studies and quality clinical trials are necessary to update treatment guidelines.

Delayed Tracheal Perforation After Microwave Ablation of Papillary Thyroid Microcarcinoma: A Case Report and Literature Review

Microwave ablation (MWA) is a relatively new, well-tolerated, minimally invasive approach, developed in recent years as an alternative to surgery for low-risk papillary thyroid microcarcinoma (PTMC). We describe an 81-year-old patient with unifocal PTMC who refused active surveillance and underwent percutaneous MWA. Two weeks after the procedure, the patient presented dyspnea and cough, and delayed tracheal perforation was confirmed by computed tomography. Conservative therapy was chosen as the initial treatment, and the tracheal defect was confirmed healing successfully 1 month later. Radiologists should be aware of the possibility of delayed tracheal perforation following MWA even in the absence of unusual intraoperative events.

Therapeutic outcomes and safety of radiofrequency ablation for primary papillary thyroid carcinoma: A game-changing meta-analysis

BACKGROUND

Radiofrequency ablation (RFA) is an emerging treatment option for small, low-risk papillary thyroid carcinoma (PTC). This systematic review and meta-analysis aimed to evaluate and compare the efficacy and safety profiles of RFA for primary T1a vs. T1b PTC.

METHODS

PubMed, Web of Science, Embase, Google Scholar, and ScienceDirect databases were searched from inception to February 14, 2024 for studies reporting outcomes of RFA for T1a vs. T1b PTC with no known nodal or distant metastasis. The primary outcomes assessed were pooled proportions of tumor disappearance, volume reduction, complications, and recurrence.

RESULTS

Twenty studies with 6,613 RFA-treated PTC nodules were included. The median age was 44 years, and the average follow-up was 36.4 months. The mean tumor volume and diameter were 168.9 mm3 and 0.69 cm, respectively. The pooled tumor disappearance rate was 94.3 % for all tumors, with rates of 96.1 % for T1a and 76.7 % for T1b lesions (p = 0.05). The disappearance rate increased from 61.8 % at 12 months to 91.5 % at 48 months post-RFA. The overall volume reduction rate (VRR) was 99.4 % for both T1a and T1b tumors, increasing from 36.8 % at 1 month to 99.6 % at 48 months. Tumor progression occurred in only 1.33 % of the cases overall, with low recurrence rates in both T1a (1.11 %) and T1b (4.21 %) lesions. New cancer foci and lymph node metastases were rare, observed in 0.81 % and 0.20 % of cases, respectively. The overall complication rate was 1.71 %, with transient voice change (0.44 %) and neck pain (0.30 %) being the most common.

CONCLUSIONS

RFA is a safe and effective minimally invasive treatment option for both T1a and T1b PTC, with high tumor disappearance and volume reduction rates and low complication and recurrence rates. The low progression rates in both tumor sizes suggest that RFA is a promising alternative to surgery for selected low-risk PTC patients. Prospective studies with standardized protocols are warranted to validate these findings.

Complications of ultrasound-guided thermal ablation of thyroid nodules and associated risk factors: an experience from 9667 cases

OBJECTIVES

To evaluate the safety of ultrasound-guided thermal ablation (UGTA) for thyroid nodules (TNs) by analysing complications and related risks.

MATERIALS AND METHODS

This retrospective, single-centre study reviewed patients who underwent UGTA (microwave or radiofrequency ablation) between January 2018 and March 2023. The incidence of complications was recorded and assessed during and immediately after ablation,1-3 h later, and at 1 month, 3 months, and 6 months. Univariate and multivariate analyses were performed to identify risk factors for hoarseness and haemorrhagic complications.

RESULTS

We reviewed 9667 cases in this study. Overall, 4494 (46.49%) cases underwent microwave ablation, while 5173 (53.51%) cases underwent radiofrequency ablation. The overall complication rate was 4.43%. The incidence of major complications was 1.94% (haemorrhage, 1.32%; hoarseness, 0.54%; and symptomatic aseptic necrosis, 0.08%). The incidence of minor complications was 2.45%. A large nodule volume, radiofrequency ablation, hyper-enhancing nodules, benign nodules, higher preoperative blood pressure, hyperthyroidism, and higher ablation power were independent risk factors for haemorrhage. Dorsal nodules and a higher ablation power were independent risk factors for hoarseness. All complications were resolved.

CONCLUSION

This study suggests that UGTA is a safe treatment for TNs. Several risk factors for haemorrhage and hoarseness should be considered before performing UGTA. Different ablation modalities should be considered for patients with different conditions.

CLINICAL RELEVANCE STATEMENT

Thermal ablation may be a safe treatment for eligible patients with TNs.

KEY POINTS

We analysed the complications and risk factors associated with UGTA in 9667 cases. The complication rate was 4.43%; 1.94% were major complications. Risk factors of haemorrhage and hoarseness should be considered. UGTA was a safe method for the treatment of TNs.

The efficacy and safety of radiofrequency ablation in papillary thyroid carcinoma: A systematic review and meta-analysis

Introduction

Radiofrequency ablation (RFA) avoids the complications of general anaesthesia, reduces length of hospitalisation and reduces morbidity from surgery. As such, it is a strong alternative treatment for patients with comorbidities who are not surgical candidates. However, to our knowledge, there have only been 1 systematic review and 3 combined systematic review and meta-analyses on this topic to date. This systematic review and meta-analysis seeks to evaluate the efficacy and safety of RFA in the treatment of papillary thyroid carcinoma (PTC) with longer follow-up durations.

Method

PubMed, Embase and Cochrane databases were searched for relevant studies published from 1990 to 2021; 13 studies with a total of 1366 patients were included. The Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines and Sandelowski et al.'s approach1 to "negotiated consensual validation" were used to achieve consensus on the final list of articles to be included. All authors then assessed each study using a rating scheme modified from the Oxford Centre for Evidence-Based Medicine.

Results

Pooled volume reduction rates (VRRs) from 1 to 48 months after RFA, complete disappearance rates (CDR) and complications were assessed. Pooled mean VRRs were 96.59 (95% confidence interval [CI] 91.05-102.13, I2=0%) at 12 months2-6 and 99.31 (95% CI 93.74-104.88, I2=not applicable) at 48 months.2,5 Five studies showed an eventual CDR of 100%.2,4,7-9 No life-threatening complications were recorded. The most common complications included pain, transient voice hoarseness, fever and less commonly, first-degree burn.

Conclusion

RFA may be an effective and safe alternative to treating PTC. Larger clinical trials with longer follow-up are needed to further evaluate the effectiveness of RFA in treating PTC.

Clinical outcomes of microwave ablation for solitary T1N0M0 papillary thyroid carcinoma: a more than 5-year follow-up study

OBJECTIVES

This study aimed to evaluate the long-term efficacy and safety of microwave ablation (MWA) for solitary T1N0M0 papillary thyroid carcinoma (PTC) and compare them between T1a and T1b disease.

MATERIALS AND METHODS

This retrospective study included 136 patients with solitary T1N0M0 PTC who were treated with MWA and followed up for more than 5 years. Outcomes were compared between patients with T1a and T1b disease. The primary outcomes were disease progression and disease-free survival (DFS). The secondary outcomes included the volume reduction rate (VRR), the rate of complete disappearance, and complications.

RESULTS

During a mean follow-up period of 70.6 ± 10.5 months, the overall disease progression rate was 5.88%. The incidences of lymph node metastases (LNMs) and new tumors were 2.21% and 5.15%, respectively. No patient was diagnosed with local recurrence, distant metastasis, or death due to PTC. There were no significant differences between the T1a and T1b groups in terms of disease progression (3.81% vs 12.90%, p = 0.15), LNMs (1.90% vs 3.23%, p = 0.54), or new tumors (2.86% vs 12.90%, p = 0.08). The 5-year DFS rate was 94.85%, the VRR was 99.7% ± 2.0%, and 97.79% of the tumors disappeared. Hoarseness occurred in five patients (3.68%).

CONCLUSION

MWA is a long-term effective and safe option for patients with solitary T1N0M0 PTC, providing a minimally invasive alternative for those who refuse surgery or active surveillance.

KEY POINTS

Question MWA, as a minimally invasive alternative for treating PTC, lacks comparison with surgical resection and active surveillance. Findings MWA resulted in overall disease progression in 5.88% of patients with solitary T1N0M0 PTC over more than 5 years of follow-up. Clinical relevance MWA is a safe, effective, and minimally invasive treatment for solitary T1N0M0 PTC, with high DFS rates and low complication rates, benefiting patients seeking alternatives to surgery or active surveillance.

Analysis and prediction of ablation zone absorption in papillary thyroid microcarcinoma undergoing microwave ablation

PURPOSE

This study aims to investigate the factors that influence the absorption of the ablation zone in patients with papillary thyroid microcarcinoma (PTMC) following microwave ablation (MWA) and construct a nomogram for predicting the absorption of the ablation zone.

METHODS

Data from 150 patients with 187 PTMCs who received MWA between April 2020 and April 2023 were analyzed. PTMCs were randomly divided into training and validation sets in a 7:3 ratio. Univariable and multivariable analyses of Cox regression were utilized to identify the independent variables associated with the absorption of the ablation zone in PTMC post-MWA, and a nomogram was established. The discrimination and calibration performance of the nomogram was assessed using the time-dependent receiver operating characteristic curves and calibration curves.

RESULTS

At 12 months post-MWA, a 53% proportion of complete disappearance of the ablation zone was observed. Energy delivered per milliliter of volume measured in contrast-enhanced ultrasound (CEUS) mode immediately post-MWA (Edv) and the CEUS margin at 1-month post-WMA were identified as independently correlated with the ablation zone absorption post-MWA (P = 0.001, P < 0.001 respectively). A nomogram incorporating these two factors was constructed. The areas under the receiver operating characteristic curve were all above 0.78 in the training and validation sets.

CONCLUSION

Edv and the CEUS margin at 1-month post-MWA were found to be significantly associated with complete absorption of the ablation zone in PTMC patients following MWA. The established nomogram can assist practitioners in formulating more appropriate ablation strategies and provide a clinical basis for explaining the recovery status to patients.

Efficacy and Oncologic Outcomes of Thermal Ablation Techniques in the Treatment of Primary Low-Risk Papillary Thyroid Carcinoma: A Systematic Review and Network Meta-Analysis

BACKGROUND

This study aimed to evaluate the safety, efficacy, and oncologic outcomes of thermal ablation techniques, including radiofrequency, laser, and microwave ablation, in treating primary thyroid cancer compared with surgical resection.

METHOD

We conducted a systematic review and network meta-analysis, which included 21 comparative studies and 40 noncomparative studies.

RESULTS

The three thermal ablation techniques showed significant superiority over surgical resection in terms of operative time, pain, cost, quality of life, and complications. Three years after the procedure, the tumor volume reduction and complete disappearance rates for the three thermal ablation techniques were similar, at approximately 99% and 93%-95%, respectively. The recurrence rate remained comparable (approximately 2%-3%) among the three thermal ablation techniques and surgical resection during a follow-up period exceeding 3 years.

CONCLUSIONS

The safety, efficacy, and oncologic outcomes of thermal ablation techniques may be acceptable and comparable to surgical resection for selected cases of primary thyroid cancer.

Is conservative treatment always safe in unifocal clinically T1a/node-negative papillary thyroid carcinoma?

BACKGROUND

Management of clinically unifocal node-negative papillary thyroid carcinoma ≤1 cm (PTMC) is controversial with nonsurgical treatment as a potential alternative to thyroid lobectomy (TL). However, conservative strategies, such as active surveillance or thermal ablation, do not allow the evaluation of biological aggressive features or occult lymph node metastases (LNMs), which play a primary role as prognostic factors.

METHODS

Among 4216 thyroidectomies for malignancy (between September 2014 and September 2023), TL plus ipsilateral central neck dissection was performed in 203 (4.8%) unifocal N0 PTMCs. Completion thyroidectomy was accomplished in case of positive frozen section examination of removed nodes or within 6 months from index operation in presence of biological aggressive features.

RESULTS

Seventy-six out of 203 (37.4%) patients were staged pN1a and extranodal extension was detected in 5 (6.6%) patients. At final histology, biological aggressive features, including multifocality, lymphovascular invasion (LVI), extracapsular invasion, tumor aggressive subtypes, and BRAF-V600E mutation, were detected in 69 (34%), 93 (45.8%), 3 (1.5%), 30 (14.8%), and 7 (3.5%) patients, respectively. A comparative analysis between pN0 and pN1a patients showed younger age (p < 0.001), LVI (p = 0.037), and multifocality (p < 0.001) as risk factors for occult central LNMs. After logistic regression analysis, age (p < 0.001) and multifocality (p < 0.001) were confirmed as independent risk factors for nodal involvement.

CONCLUSIONS

Although most PTMC has been widely defined as indolent disease, a non-negligible rate of patients may present one or more biologically aggressive features including nodal involvement. Nonsurgical management should be considered with caution to avoid undertreatment especially in the younger population.

Is ultrasound-guided radiofrequency ablation a reliable treatment option for unifocal T1aN0M0 papillary thyroid carcinoma in the isthmus: a retrospective comparative study based on large-sample data

OBJECTIVE

To evaluate whether ultrasound-guided radiofrequency ablation (RFA) is reliable for unifocal T1aN0M0 papillary thyroid carcinoma in the isthmus (PTCI).

METHODS

431 patients who underwent ultrasound-guided RFA for unifocal T1aN0M0 papillary thyroid carcinoma (PTC) were divided by location of the lesion into the PTCI group (52 females, 7 males, mean age 43.79 ± 12.04 years, range 22-74 years) and the PTCL group ((291 females, 81 males, mean age 43.42 ± 10.87 years, range 18-75 years) for comparative analysis. The efficacy of ultrasound-guided RFA was evaluated by volume reduction rate (VRR), complete disappearance rate (CDR) and disease progression, and the safety was evaluated by incidence of complications.

RESULTS

The two groups exhibited a consistent trend of change, with the PTCI group performing better in volume, VRR and CDR at all follow-up time points expect 1 month, but the differences were not statistically significant (p > 0.05). The mean initial volume of the PTCI group vs the PTCL group decreased significantly from 65.4 ± 69.79 vs 86.38 ± 87.09 mm³ (range 10.92-427.58 vs 3.05-471.6 mm³) to 0 vs 0 mm³ at a mean follow-up time of 31.12 ± 12.5 months (range 12-60 months); their VRR increased significantly from -618.62 ± 655.61% vs -789.85 ± 1135.07% at 1 month to 100% vs 100% at 48 months. No disease progression was found in the two groups. The PTCI group had no complications, whereas the PTCL group had a total of 7 complications (1.88%).

CONCLUSIONS

Ultrasound-guided RFA is reliable for unifocal T1aN0M0 PTCI. It can be promoted as an alternative to immediate surgery for selected PTC patients.

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 and safety of laser ablation and microwave ablation to treat papillary thyroid microcarcinoma: A retrospective study

OBJECTIVE

To retrospectively analyze the efficacy and safety of laser ablation (LA) and microwave ablation (MWA) in the treatment of papillary thyroid microcarcinoma (PTMC).

METHODS

This was a retrospective study of 103 patients (109 nodules) who underwent thermal ablation for PTMC between October 2019 and March 2023; 61 underwent LA and 48 underwent MWA. The mean patients' age was 43.50 ± 12.42 years. After ablation, changes in tumor size at different time points, local recurrence, new lesions, lymph node metastasis, and complications were evaluated and recorded. The feasibility, success rate, and safety of LA and MWA were analyzed.

RESULTS

Complete absence of enhancement on contrast-enhanced ultrasonography was observed in all target tumors after ablation. At the last follow-up, the mean volume of the PTMC nodules decreased from 0.09 ± 0.09 to 0.03 ± 0.03 ml (LA group) and from 0.11 ± 0.10 to 0.06 ± 0.08 ml (MWA group) (both, P < 0.05). There was no significant difference in volume change between the groups (P (groups): 0.520; P (groups over time): 0.423), indicating similar efficacy between the groups. There was also no significant difference in the volume reduction rate between the groups during follow-up, except for at 3 months (P = 0.023). The complication rates did not differ between the LA group (8.2 %) and MWA group (6.3 %) (P > 0.05).

CONCLUSION

During the short-term follow-up, ultrasound-guided LA and MWA were effective and safe for PTMC, and there were no significant differences in treatment outcomes between the methods.

Ultrasound-guided ablation for T1N0M0 papillary thyroid carcinoma adjacent and non-adjacent danger triangle area: a retrospective comparative study

OBJECTIVES

To compare the safety and efficacy of ultrasound-guided radiofrequency ablation (RFA) in the treatment of T1N0M0 papillary thyroid carcinoma (PTC) with adjacent and non-adjacent danger triangle area (DTA).

MATERIALS AND METHODS

This retrospective study involved collecting clinical data of all T1N0M0 PTC patients who underwent RFA between January 2018 and December 2020 at the hospital. A total of 211 patients were enrolled in the study (mean age 43.25 ± 12.30 years, male-to-female ratio = 1:3). Among them, 91 had adjacent DTA involvement, while 120 had non-adjacent DTA involvement. Comparisons were made between the two groups patients regarding tumor volume changes, technical success rates, tumor disappearance, disease progression, complications.

RESULTS

In both groups, the technical success rate was 100%, with a median follow-up period of 30 months. The rates of complete tumor disappearance were 78% (71/91) and 74.2% (89/120) for the adjacent and non-adjacent DTA(p = .517). Disease progression rates were 2.2% (2/91) and 1.7% (2/120) (p > .99), Complication rates were 3.3%(3/91) in the adjacent DTA group and 1.7% (2/120) in the non-adjacent DTA group (p = .654). At 6th month after ablation, the volume reduction rate (VRR) in the non-adjacent DTA group (42.3%) was higher than in the adjacent DTA group (37.3%) (p = .002). However, no significant differences were observed in VRR between the two groups at 1, 3, 12, 18, 24, 30, and 36 months (p > .05).

CONCLUSION

In the treatment of T1N0M0 PTC, the complication rates and short-term efficacy of RFA in adjacent to the DTA did not differ from those of non-adjacent DTA.

The relationship between ablation range and ablation energy in papillary thyroid microcarcinoma: a comparison between microwave ablation and laser ablation

OBJECTIVES

To study the relationship between the ablation range and applied energy of laser ablation (LA) and microwave ablation (MWA) in papillary thyroid microcarcinoma (PTMC).

METHODS

A total of 201 PTMC patients were treated with LA (n = 102) or MWA (n = 99) with single-applicator fixed ablation. The ablation range was determined by contrast-enhanced ultrasound. The ratios of ablation volume, longitudinal diameter, and orthogonal diameter to ablation energy (RAV/E, RAL/E, RAO/E) were analyzed and compared between MWA and LA. The effects of PTMC characteristics and Hashimoto's thyroiditis (HT) on ablation efficiency were evaluated by linear regression.

RESULTS

The RAV/E was 0.72 (0.65-0.84) mm3/J for MWA and 0.48 (0.39-0.54) mm3/J for LA. HT was significantly correlated with RAV/E of LA (coefficient =  - 0.367, p < 0.0001). RAL/E did not differ significantly between MWA and LA (MWA 0.026 mm/J, LA 0.025 mm/J; p = 0.957). However, MWA had a greater RAO/E than LA (MWA 0.014 mm/J, LA 0.012 mm/J; p < 0.0001). The plateau values of MWA and LA on the ablation orthogonal diameter were 10.7 mm and 8.69 mm, respectively.

CONCLUSIONS

MWA showed a higher RAV/E than LA. More intuitively, MWA had a better ablation performance than LA on the orthogonal axis rather than the longitudinal axis. Theoretically, MWA and LA could achieve complete ablation of ≤ 6.70 mm and ≤ 4.69 mm PTMC separately by single-applicator fixed ablation considering a unilateral 2-mm safe margin. HT had a negative effect on LA but not on MWA.

CLINICAL RELEVANCE STATEMENT

This study establishes strong connections between ablation energy and ablation range in papillary thyroid microcarcinoma (PTMC) in vivo, possibly contributing to the supplementation of the PTMC Ablation Consensus or Guidelines and providing a scientific basis for choosing clinical ablation parameters in PTMC.

KEY POINTS

• Both microwave ablation (MWA) and laser ablation (LA) have excellent performance on the ablation longitudinal axis (easily exceeding 10 mm) for papillary thyroid microcarcinoma (PTMC). • MWA performed much better than LA on the ablation orthogonal axis. • MWA and LA are expected to achieve complete ablation of ≤ 6.70 mm and ≤ 4.69 mm PTMC separately by single-applicator fixed ablation considering a unilateral 2-mm safe margin.

Comparison between thermal ablation and surgery in low risk papillary thyroid carcinoma: a prospective study

Objective

To conduct a comparative analysis of the efficacy, safety, and impact on quality of life outcomes between thermal ablation and surgical interventions in patients diagnosed with papillary thyroid carcinoma (PTC).

Methods

A prospective study was undertaken, enrolling patients with PTC ≤5mm who underwent radiofrequency ablation (RFA), laser ablation (LA), or surgery, for analysis of efficacy and safety outcomes. The Thyroid Cancer-Specific Quality of Life questionnaire was administered to all patients before treatment and at 3, 6, and 12 months post-treatment.

Results

A total of 162 eligible patients were included in the study. Major complications were not observed in the RFA and LA groups, while five cases were reported in the surgery group, although no statistically significant differences were observed. Minor complications were documented in two, three, and 14 patients in the RFA, LA, and surgery groups, respectively, with no significant variances noted. Surgical duration and hospitalization time were notably shorter in the thermal ablation groups. At the final follow-up, complete disappearance of nodules was seen in 71.4% of cases treated with RFA and 71.0% of cases managed with LA, with no significant disparities between the groups. Both RFA and LA exhibited similar effects on quality of life, with thermal ablation techniques showing better functional outcomes in comparison to surgery. Across all groups, adverse effects were most pronounced at the 3-month post-treatment mark but gradually reverted to baseline levels in the thermal ablation group, contrasting with the surgery group.

Conclusions

For PTC ≤5mm, both RFA and LA exhibited similar cancer control outcomes and superior quality of life on par with surgery, while minimizing complications. These findings underscore the promise of RFA and LA as potential standard treatments for small PTCs, subject to further confirmation in future studies.

Advances in Image-Guided Ablation Therapies for Solid Tumors

Image-guided solid tumor ablation methods have significantly advanced in their capability to target primary and metastatic tumors. These techniques involve noninvasive or percutaneous insertion of applicators to induce thermal, electrochemical, or mechanical stress on malignant tissue to cause tissue destruction and apoptosis of the tumor margins. Ablation offers substantially lower risks compared to traditional methods. Benefits include shorter recovery periods, reduced bleeding, and greater preservation of organ parenchyma compared to surgical intervention. Due to the reduced morbidity and mortality, image-guided tumor ablation offers new opportunities for treatment in cancer patients who are not candidates for resection. Currently, image-guided ablation techniques are utilized for treating primary and metastatic tumors in various organs with both curative and palliative intent, including the liver, pancreas, kidneys, thyroid, parathyroid, prostate, lung, breast, bone, and soft tissue. The invention of new equipment and techniques is expanding the criteria of eligible patients for therapy, as now larger and more high-risk tumors near critical structures can be ablated. This article provides an overview of the different imaging modalities, noninvasive, and percutaneous ablation techniques available and discusses their applications and associated complications across various organs.

Thermal ablation for multifocal papillary thyroid microcarcinoma: a systematic review and meta-analysis

BACKGROUND

Clinical studies have indicated the potential safety and efficacy of thermal ablation (TA) in treating multifocal papillary thyroid microcarcinoma (MPTMC). However, a comprehensive systematic evaluation of its effectiveness was still lack.

METHODS

PubMed, EMBASE and Cochrane Library databases were systematically searched for studies published until October 23, 2023, that reported on the effectiveness of thermal ablation in the management of MPTMC. Data extraction and methodological quality assessment were independently conducted by two reviewers following the guidelines outlined in the PRISMA.

RESULTS

This systematic review and meta-analysis identified 389 tumors in 169 patients from four studies. After treatment with different TA, the combined rate of complete disappearance of MPTMC was 92.8% [95% confidence interval (CI): 68.2-100] and the combined rate of overall complications was 4.4% [95% CI: 1.5-8.5]. During the follow-up period, local tumor recurrence was observed in only 2 patients with a combined rate of 0.2% [95% CI: 0.0-2.6]; lymph node metastasis (LNM) was observed in 3 patients with a combined rate of 1.2% [95% CI: 0-4.1]. Additionally, 6 patients developed new PTMC. It is noteworthy that no patients were observed to develop distant metastases during the follow-up period, and no patients had delayed surgery after underwent ablation.

CONCLUSIONS

For patients grappling with MPTMC, TA emerges as an excellent approach for achieving localized tumor control. Nonetheless, achieving favorable outcomes necessitates stringent inclusion criteria and a profound level of expertize.

Radiofrequency ablation for capsular-located versus noncapsular-located papillary thyroid microcarcinoma: a propensity score matching study of 1095 patients

OBJECTIVES

To assess the safety and efficacy of radiofrequency ablation (RFA) for capsular-located papillary thyroid microcarcinoma (PTMC) in a large cohort and to compare its outcomes with those of noncapsular-located PTMC.

METHODS

We retrospectively reviewed patients who underwent RFA for solitary capsular-located and noncapsular-located low-risk PTMC (n = 1095) from June 2014 to October 2020. To balance confounding variables between capsular and noncapsular groups, we employed the 1:1 propensity score matching approach. We evaluated and compared tumor changes, disease progression, and complications in both groups. Furthermore, we analyzed the association between capsular location and disease progression using multivariable Cox regression.

RESULTS

During a mean follow-up time of 29.86 ± 16.14 months and 29.73 ± 15.69 months, no substantial difference was observed between capsular and noncapsular groups in the latest volume (0.83 ± 3.66 mm3 vs. 0.85 ± 3.67 mm3, p = 0.44) and volume reduction ratio (99.29 ± 4.04% vs. 99.43 ± 3.03%, p = 0.43), and cumulative disappearance rate (87.87% vs. 86.07%, p = 0.31). In addition, no significant differences were observed in complication incidence (1.35% vs. 1.12%, p = 0.76) and progression-free survival (p = 0.53). Based on adjusted multivariate Cox proportional hazard analysis, the association between capsular location and disease progression was nonsignificant (all p > 0.05).

CONCLUSION

This study demonstrates that the short-term outcomes of RFA for capsular-located PTMCs are comparable to those of noncapsular-located PTMCs. These findings indicate that RFA may be a viable and effective alternative for eligible patients with solitary capsular-located PTMC.

CLINICAL RELEVANCE STATEMENT

Radiofrequency ablation may serve as a safe and effective alternative treatment method for eligible patients with capsular-located and noncapsular-located papillary thyroid microcarcinoma.

KEY POINTS

• The safety and efficacy of radiofrequency ablation for capsular-located and noncapsular-located papillary thyroid microcarcinomas were comparable. • Disease progression did not differ significantly between capsular-located and noncapsular-located papillary thyroid microcarcinomas. • The incidence of complications for capsular-located papillary thyroid microcarcinoma was low.

Sublethal thermal stress promotes migration and invasion of thyroid cancer cells

OBJECTIVE

Radiofrequency ablation is a viable option in the treatment of benign thyroid nodules. Some reports suggest that thermal ablation may also be safe for the management of low-risk thyroid cancer. In this study, we applied transient heat treatment to thyroid cancer cells to mimic clinical scenarios in which insufficient ablation leads to incomplete eradication of thyroid cancer.

METHODS

Differentiated thyroid cancer cell lines B-CPAP, TPC-1, and FTC-133 were subjected to heat treatment at different temperatures for 10 min. Effects on cell growth, clonogenicity, wound healing assay, and Transwell invasion were determined.

RESULTS

Heat treatment at 45°C or higher reduced cell growth, whereas viability of thyroid cancer cells was not changed after heat treatment at 37, 40, or 42°C. Heat treatment at 40°C increased the number of colony formations by 16% to 39%. Additionally, transient heat treatment at 40°C resulted in a 1.75-fold to 2.56-fold higher migratory activity than treatment at 37°C. Invasive capacity was increased after heat treatment, ranging from 115% to 126%. Expression of several epithelial-mesenchymal transition markers, including ZEB1, N-cadherin, and MMP2, was upregulated following heat treatment at 40°C.

CONCLUSION

We for the first time demonstrate that sublethal thermal stress may increase clonogenicity, migration, and invasion of thyroid cancer cells.

Efficacy and safety of thermal ablation modalities for the treatment of papillary thyroid microcarcinoma: Systematic Review and network meta-analysis

Background

Thermal ablation (TA) modalities such as radiofrequency ablation (RFA), microwave ablation (MWA), and laser ablation (LA) have been widely used in the treatment of papillary thyroid microcarcinoma (PTMC) patients. Based on previous small-sample meta-analyses, this network meta was designed to further compare the efficacy and safety of these thermal ablation methods in PTMC patients.

Methods

China National Knowledge Infrastructure (CNKI), Wanfang, PubMed, Embase, and the Cochrane Library databases were searched to retrieve relevant studies published before May 2022. The efficacy outcomes was recurrence and lymph node metastasis (LNM), the safety outcome included operation time, intra-operative blood loss, hospital stays and complications. The Newcastle-Ottawa Scale (NOS) was selected for the risk of bias assessment. Stata 14.0 was used for statistical analysis.

Results

Twenty-nine articles were included. Based on as least 6 months follow up, our analysis discovered no significant statistical differences in all efficacy and safety outcomes between MWA, RFA, and LA groups. Moreover, three TA treatments all produced significant least operation time, hospital stays, and complications than surgery group. Additionally, our study found that RFA showed relatively less complications, LNM, operation time and intra-operative blood loss, compared with other TA treatments. MWA indicated the lowest probability of recurrence, LA showed the longest hospital stays.

Conclusions

MWA, RFA, and LA are all effective treatment strategies for patients with PTMC, but could not completely replace conventional surgical treatment.

Thirty years of active surveillance for low-risk thyroid cancer, lessons learned and future directions

Active Surveillance is a non-invasive strategy designed to identify a minority of patients with low-risk papillary thyroid carcinoma who might experience clinical progression and benefit from additional definitive treatments. Global experience suggests that these tumors typically show minimal changes in size during active surveillance, often demonstrating very slow growth or even size reduction. Moreover, the rate of lymph node metastases is low and can be effectively managed through rescue surgery, without impacting cancer-related mortality. However, despite 30 years of experience demonstrating the safety and feasibility of active surveillance for appropriately selected patients, this approach seems to have limited adoption in specific contexts. This limitation can be attributed to various barriers, including disparities in access to accurate information about the indolent nature of this disease and the prevalence of a maximalist mindset among certain patients and medical settings. This review aims to revisit the experience from the last three decades, provide current insights into the clinical outcomes of active surveillance trials, and propose a systematic approach for its implementation. Furthermore, it intends to emphasize the importance of precise patient selection and provides new perspectives in the 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.

Radiofrequency Ablation for Benign Nodules and for Cancer, Too?

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

Radiofrequency ablation for papillary thyroid microcarcinoma with a trachea-adjacent versus trachea-distant location

OBJECTIVE

To evaluate the outcomes of radiofrequency ablation (RFA) for papillary thyroid microcarcinoma (PTMC) adjacent to the trachea and compare them with those of PTMC distant from the trachea.

METHODS

Patients who received RFA for solitary low-risk PTMC between June 2014 and July 2020 were reviewed and classified into adjacent and distant groups. To balance between-group confounders, the propensity score matching approach was employed. Volume, volume reduction ratio (VRR), tumor disappearance, complications, and disease progression were assessed and compared between the groups. Furthermore, factors affecting disease progression were evaluated.

RESULTS

A total of 122 and 470 patients were included in the adjacent and distant groups, respectively. Overall VRR was 99.5% ± 3.1 and cumulative tumor disappearance rate was 99.4% after a mean follow-up time of 40.1 months ± 16.2. Overall disease progression and complications incidence were 3.7% and 1.0%, respectively. No substantial differences were observed between the two groups in the latest volume (0.8 mm3 ± 4.1 vs. 0.9 mm3 ± 4.2, p = .77), VRR (99.7% ± 1.6 vs. 99.5% ± 2.7, p = .75), cumulative tumor disappearance rate (92.6% vs. 94.2%, p = .58), and incidence of disease progression (4.1% vs. 4.5%, p = .70) and complication (1.7% vs. 0.8%, p = .86) after 1:2 matching. Additionally, tracheal adjacency exhibited no association with disease progression in multivariate Cox regression analysis (p = .73).

CONCLUSION

For eligible patients with PTMC located adjacent to or distant from the trachea, RFA may offer a safe and effective alternative treatment method.

Sonographic Evolution and Pathologic Findings of Papillary Thyroid Cancer After Radiofrequency Ablation: A Five-Year Retrospective Cohort Study

Background: The criteria for determining technical efficacy of thermal ablation for papillary thyroid carcinoma (PTC) are not clearly defined. We analyzed the involution process of the ablation zone with clear pathologic results on core-needle biopsy (CNB) to clarify the relationship between sonographic changes and pathologic findings. Methods: This retrospective cohort study included 382 patients with unifocal T1N0M0 PTC who underwent radiofrequency ablation (RFA) between May 2014 and August 2021. Patients with a single ablation zone biopsy (recommended at 3 or 6 months for T1a and 6 or 12 months for T1b) and regular neck ultrasound (US)/contrast-enhanced ultrasound imaging follow-up at 1, 3, 6, and 12 months and every 6-12 months thereafter after RFA were included. Patients also underwent yearly chest computed tomography. CNB was performed in the target lesion ablation zone's central, peripheral, and surrounding thyroid parenchyma to detect the presence of tumor cells. If the thyrotropin (TSH) was >2 mU/L, levothyroxine was prescribed with the intention of keeping the TSH 0.5-2 mU/L. Technical efficacy was defined as tumor disappearance by imaging follow-up together with the pathologically confirmed absence of tumor cells in the ablation zone. Results: During the mean follow-up period of 67.8 ± 18.2 months (22-110 months), the overall incidence of persistent disease and the technical efficacy rate were 3.9% (15/382; 2.9% of T1a, and 12.2% of T1b) and 96.1%, respectively. Tumor size (p = 0.03) and subcapsular location (p = 0.04) were risk factors associated with persistent disease. The technical success rate was 100%. Of the 367 ablation zones with benign CNB results, 336 (91.6%) showed tumor disappearance on US and no re-emergence of imaging-visible tumors during follow-up. Male sex (p = 0.006), age <40 years (p = 0.003), T1a tumor (p < 0.01), and energy per milliliter (p < 0.03) were significantly associated with tumor disappearance. Conclusions: US-guided RFA is an effective treatment for small low-risk PTC. Tumor disappearance on US after RFA may suggest an excellent prognosis and confirm complete ablation of the macroscopic tumor, but this sonographic finding is generally late and requires histological confirmation.

Efficacy and safety of ultrasound-guided radiofrequency, microwave and laser ablation for the treatment of T1N0M0 papillary thyroid carcinoma on a large scale: a systematic review and meta-analysis

BACKGROUND

To analyze the efficacy and safety of radiofrequency ablation (RFA), microwave ablation (MWA) and laser ablation (LA) in T1N0M0 papillary thyroid carcinoma (PTC) patients by evaluating data on several outcomes on a large scale.

MATERIALS AND METHODS

Literature searches were conducted in PUBMED, EMBASE and the Cochrane Library for studies of thermal ablation (TA) for treating T1N0M0 PTC. Data on the volume reduction rate (VRR) at the 12-month follow-up and final follow-up, complete disappearance rate, local recurrence rate, lymph node metastasis rate, and complication rate of RFA, MWA and LA were evaluated separately. RFA effects were compared between T1aN0M0 and T1bN0M0 patients.

RESULTS

A total of 36 eligible studies were included. RFA presented superior efficacy than MWA in 12-month VRR. At the final follow-up, the difference was slight in subgroups, showing a significant reduction. The complete disappearance rate of LA (93.00%) was higher than that of RFA (81.00%) and MWA (71.00%). Additionally, the local recurrence rate pooled proportions of MWA and RFA were both 2.00%, lower than that of the LA group (3.00%). There was no event of distant metastasis. The lymph node metastasis rates were similar, as RFA (1.00%) had the lowest. For minor complication rates, the pooled proportions of RFA (3.00%) were smaller than those of LA (6.00%) and MWA (13.00%). T1aN0M0 lesions presented with better outcomes than T1bN0M0 lesions.

CONCLUSION

RFA, MWA and LA were reliable in curing PTC, and RFA presented advantages in most outcomes. T1aN0M0 patients may experience fewer side effects than T1bN0M0 patients.

Five-year Outcome Between Radiofrequency Ablation vs Surgery for Unilateral Multifocal Papillary Thyroid Microcarcinoma

CONTEXT

Ultrasound (US)-guided radiofrequency ablation (RFA) has been considered as an alternative to surgery or active surveillance for papillary thyroid microcarcinoma (PTMC). However, little is known about the long-term outcomes of RFA in comparison with surgery for unilateral multifocal PTMC.

OBJECTIVE

This work aims to report the comparison between RFA vs surgery for unilateral multifocal PTMC over a more than 5-year follow-up period.

METHODS

This was a retrospective study at a primary care center with a median follow-up period of 72.9 months. A total of 97 patients with unilateral multifocal PTMC were treated with RFA (RFA group, n = 44) or surgery (surgery group, n = 53). In the RFA group, patients were treated by a bipolar RFA generator and an 18-gauge bipolar RF electrode with a 0.9-cm active tip. In the surgery group, patients underwent thyroid lobectomy with prophylactic central neck dissection.

RESULTS

During the follow-up, no statistically significant differences were found in disease progression (4.5% vs 3.8%; P = ≥.999), lymph node metastasis (2.3% vs 3.8%; P = ≥.999), persistent lesion (2.3% vs 0%; P = .272), and RFS rates (97.7% vs 96.2%; P = .673) in the RFA and surgery groups. Patients undergoing RFA had a shorter hospitalization (0 vs 8.0 [3.0] d; P < .001), shorter procedure time (3.5 [2.4] vs 80.0 [35.0] min; P < .001), lower estimated blood loss (0 vs 20.0 [15.0] mL; P < .001), and lower costs ($1768.3 [0.1] vs $2084.4 [1173.8]; P = .001) than those in the surgery group. The complication rate in the surgery group was 7.5%, whereas none of the RFA-treated patients experienced any complications (P = .111).

CONCLUSION

This study revealed 6-year comparable outcomes between RFA and surgery for unilateral multifocal PTMC. RFA may be a safe and effective alternative to surgery in selected patients with unilateral multifocal PTMC.

Ultrasound-guided thermal ablation for papillary thyroid microcarcinoma: the devil is in the details

Thermal ablation (TA) has harvested favorable outcomes in treating low-risk papillary thyroid microcarcinoma (PTMC). Preoperative assessment, intraoperative procedures and postoperative follow-up are all closely linked with the success and safety of TA on PTMC. However, many details in these aspects have not been systematically reviewed. This review firstly described the influence of preoperative assessment, especially for the risk of lymph node metastasis (LNM), as well as the molecular testing on the selection of TA for PTMC. Besides, we also summarized the experiences in treating special PTMC cases by TA, like multifocal lesions, PTMC located in the isthmus or adjacent to the dorsal capsule. At last, we discussed the follow-up strategies, the influence of the thyroid-stimulating hormone (TSH) level on the prognosis of PTMCs, and the management for recurrent cases. In conclusion, the procedures during the entire perioperative period should be standardized to improve the outcomes of TA in treating PTMC patients.

Safety and efficacy of microwave ablation for the treatment of low-risk papillary thyroid microcarcinoma: a prospective multicenter study

OBJECTIVES

To assess the safety and efficacy of ultrasound-guided thermal ablation for low-risk papillary thyroid microcarcinoma (PTMC) via a prospective multicenter study.

METHODS

From January 2017 through June 2021, low-risk PTMC patients were screened. The management details of active surveillance (AS), surgery, and thermal ablation were discussed. Among patients who accepted thermal ablation, microwave ablation (MWA) was performed. The main outcome was disease-free survival (DFS). The secondary outcomes were tumor size and volume changes, local tumor progression (LTP), lymph node metastasis (LNM), and complication rate.

RESULTS

A total of 1278 patients were included in the study. The operation time of ablation was 30.21 ± 5.14 min with local anesthesia. The mean follow-up time was 34.57 ± 28.98 months. Six patients exhibited LTP at 36 months, of whom 5 patients underwent a second ablation, and 1 patient received surgery. The central LNM rate was 0.39% at 6 months, 0.63% at 12 months, and 0.78% at 36 months. Of the 10 patients with central LNM at 36 months, 5 patients chose ablation, 3 patients chose surgery and the other 2 patients chose AS. The overall complication rate was 1.41%, and 1.10% of patients developed hoarseness of the voice. All of the patients recovered within 6 months.

CONCLUSIONS

Thermal ablation of low-risk PTMC was observed to be safe and efficacious with few minor complications. This technique may help to bridge the gap between surgery and AS as treatment options for patients wishing to have their PTMC managed in a minimally invasive manner.

CLINICAL RELEVANCE STATEMENT

This study proved that microwave ablation is a safe and effective treatment method for papillary thyroid microcarcinoma.

KEY POINTS

Percutaneous US-guided microwave ablation of papillary thyroid microcarcinoma is a very minimally invasive treatment under local anesthesia during a short time period. The local tumor progression and complication rate of microwave ablation in the treatment of papillary thyroid microcarcinoma are very low.

Radiofrequency Ablation of Unifocal Papillary Thyroid Microcarcinoma With BRAF V600E Mutation

CONTEXT

To date there is no study on the feasibility of radiofrequency ablation (RFA) for papillary thyroid microcarcinomas (PTMCs) with BRAF V600E mutation.

OBJECTIVE

This study was designed to evaluate the efficiency, safety, and prognosis of ultrasound (US)-guided percutaneous RFA for unifocal PTMCs with BRAF V600E mutation.

MATERIALS AND METHODS

Sixty patients with 60 unifocal BRAF V600E mutation-positive PTMCs who received US-guided RFA between January 2020 and December 2021 were retrospectively analyzed. The mean maximum PTMC tumor diameter was 5.8 ± 1.7 mm (range, 2.5-10.0 mm). All PTMCs were pathologically confirmed by fine needle aspiration or core needle biopsy, and BRAF V600E mutation was confirmed to be positive by real-time fluorescent quantitative polymerase chain reaction. Contrast-enhanced ultrasound (CEUS) was performed immediately after RFA to evaluate whether PTMCs were extendedly ablated. Ultrasound was performed 1, 3, 6, and 12 months after RFA and every 6 months thereafter to evaluate the changes in the ablation zone, local recurrence, and cervical lymph node metastasis (LNM). The complications were recorded and evaluated.

RESULTS

Extended ablation was achieved in all enrolled patients. The ablation zone sizes increased immediately after RFA compared with those of tumors before treatment. One month later, the ablation zone sizes were smaller than immediately after RFA. At the last follow-up assessment, 42 nodules (70.0%) completely disappeared and the ablation zones of 18 nodules (30.0%) showed fissure-like changes. No local recurrence or cervical LNM was detected. Voice change (1.7%) was the only major complication.

CONCLUSION

RFA is effective and safe in treating unifocal PTMCs with BRAF V600E mutation, especially when surgery is not feasible or refused by patients who are unwilling to continue active surveillance.

Publications on ultrasound-guided thermal ablation for thyroid nodules from 2000 to 2022: a bibliometric analysis

BACKGROUND

Thyroid nodules are increasingly treated with minimally invasive surgery. Thermal ablation could efficiently treat patients with benign thyroid nodules, recurrent thyroid cancer, and low-risk papillary thyroid carcinoma. This research aims to explore the research field of thermal ablation for thyroid nodules using bibliometric analysis.

METHODS

The web of science core collection (WoSCC) database was utilized from its inception to 1 October 2022, to collect research articles and reviews on ultrasound-guided thermal ablation for thyroid nodules. We applied the R package 'bibliometrix' to summarize the main findings, calculate the occurrences of the top keywords and visualize the international collaboration networks. The co-authorship and co-occurrence analyses were conducted with VOSviewer software. CiteSpace was used to identify the top references and keywords with the highest citation bursts.

RESULTS

A total of 820 publications from 32 countries were retrieved. The annual number of related publications showed an increasing trend. China, Italy, and Korea were the most contributing countries. The University of Ulsan College of Medicine in Korea was the most productive institution, and Jung Hwan Baek published the maximum number of articles. The International Journal of Hyperthermia was the most productive journal. 'Papillary thyroid micro-carcinoma (PTMC)' and 'association guideline' were the most frequently used keywords in the field of thermal ablation for thyroid nodules, which indicated the potential hot research topics and frontiers in the future.

CONCLUSION

This bibliometric study conducts a comprehensive analysis of publications on thermal ablation for thyroid nodules, which aids investigators in discovering potential research directions.

Deep learning prediction model for central lymph node metastasis in papillary thyroid microcarcinoma based on cytology

Controversy exists regarding whether patients with low-risk papillary thyroid microcarcinoma (PTMC) should undergo surgery or active surveillance; the inaccuracy of the preoperative clinical lymph node status assessment is one of the primary factors contributing to the controversy. It is imperative to accurately predict the lymph node status of PTMC before surgery. We selected 208 preoperative fine-needle aspiration (FNA) liquid-based preparations of PTMC as our research objects; all of these instances underwent lymph node dissection and, aside from lymph node status, were consistent with low-risk PTMC. We separated them into two groups according to whether the postoperative pathology showed central lymph node metastases. The deep learning model was expected to predict, based on the preoperative thyroid FNA liquid-based preparation, whether PTMC was accompanied by central lymph node metastases. Our deep learning model attained a sensitivity, specificity, positive prediction value (PPV), negative prediction value (NPV), and accuracy of 78.9% (15/19), 73.9% (17/23), 71.4% (15/21), 81.0% (17/21), and 76.2% (32/42), respectively. The area under the receiver operating characteristic curve (value was 0.8503. The predictive performance of the deep learning model was superior to that of the traditional clinical evaluation, and further analysis revealed the cell morphologies that played key roles in model prediction. Our study suggests that the deep learning model based on preoperative thyroid FNA liquid-based preparation is a reliable strategy for predicting central lymph node metastases in thyroid micropapillary carcinoma, and its performance surpasses that of traditional clinical examination.

Incidence and risk factors for occult lesions in low-risk papillary thyroid microcarcinoma patients with tumor characteristics appropriate for thermal ablation: A retrospective study

In recent years, thermal ablation has been increasingly employed for the treatment of low-risk papillary thyroid microcarcinoma (PTMC) across various institutions. Its use as a standard or initial treatment continues to be a subject of debate. Retrospective analyses of the surgical pathology in post-ablation patients have indicated that occult lesions are not uncommon. This retrospective study aimed to examine the incidence and risk factors of occult lesions via postoperative pathology in low-risk PTMC patients who fulfilled the criteria for thermal ablation therapy. We examined the medical records of patients who underwent thyroid surgery and had a Bethesda classification V or VI based on fine needle aspiration cytology between November 22, 2020, and December 31, 2022. A total of 413 patients with preoperative tumor characteristics appropriate for thermal ablation were included in this study. Occult lesions, encompassing ipsilateral or contralateral occult carcinoma or central lymph node metastases may have occurred in 34.7% of patients. Male gender (OR: 2.526, 95% CI: 1.521-4.195, P = .000), tumor location in the lower pole (OR: 1.969, 95% CI: 1.186-3.267, P = .009), multiple microcalcifications (OR: 5.620, 95% CI: 2.837-11.134, P = .000), and Hashimoto's thyroiditis (OR: 2.245, 95% CI: 1.292-3.899, P = .004) were independent risk factors for the presence of occult lesions. In low-risk PTMC patients exhibiting tumor characteristics amenable to thermal ablation, over one-third of the patients may present with occult lesions. Meticulous evaluation of the presence of additional lesions is necessary before performing thermal ablation, particularly in patients exhibiting high-risk factors for occult lesions.

Choice in Ablative Therapies for Thyroid Nodules

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

Long-term Outcomes of Ultrasound-guided Thermal Ablation for the Treatment of Solitary Low-risk Papillary Thyroid Microcarcinoma: A Multicenter Retrospective Study

OBJECTIVE

To report more than 5-year outcomes of ultrasound-guided thermal ablation (TA) for patients with solitary low-risk papillary thyroid microcarcinoma (PTMC) in a large multicenter cohort.

BACKGROUND

TA, including radiofrequency ablation (RFA) and microwave ablation (MWA) have been used in patients with low-risk PTMC who refuse surgery or active surveillance. However, its clinical value remains controversial.

MATERIALS AND METHODS

This retrospective multicenter study included 474 patients with solitary low-risk PTMC treated with TA (357 for RFA; 117 for MWA) from 4 centers and followed up for at least 5 years. Disease progression including lymph node metastasis and recurrent tumors, volume reduction rate (VRR), tumor disappearance rate, complications, and delayed surgery were assessed. RFA and MWA outcomes were compared using propensity score matching.

RESULTS

During the median follow-up period of 77.2 months, disease progression incidence, lymph node metastasis, and recurrent tumors rates were 3.6%, 1.1%, and 2.5%, respectively. Age below 40 years old, male sex, Hashimoto thyroiditis, and tumor size were not independent factors associated with disease progression by Cox analysis. The median VRR was 100% and 471 tumors disappeared radiographically. Eight patients experienced transient voice change (1.7%) which recovered within 3 months. None of the patients underwent delayed surgery because of anxiety. After 1:1 matching, no significant differences were found in the disease progression, VRR, tumor disappearance rate, or complications between RFA and MWA subgroups.

CONCLUSION

This multicenter study revealed that TA was an effective and safe treatment for patients with solitary low-risk PTMC, which could be offered as a treatment option for the management for low-risk PTMC.

Microwave Ablation for Papillary Thyroid Microcarcinoma with and without US-detected Capsule Invasion: A Multicenter Prospective Cohort Study

Background Microwave ablation (MWA) has achieved favorable results in the treatment of papillary thyroid microcarcinoma (PTMC) confined in glandular parenchyma. However, studies on the outcome of MWA for PTMC with US-detected capsular invasion remain unclarified in the literature. Purpose To compare the feasibility, effectiveness, and safety of MWA in the treatment of PTMC with and without US-detected capsular invasion. Materials and Methods Participants from 12 hospitals with a PTMC maximal diameter of 1 cm or less without US- or CT-detected lymph node metastasis (LNM) who planned to undergo MWA were enrolled in this prospective study between December 2019 and April 2021. All tumors were evaluated with preoperative US and were divided into those with and those without capsular invasion. The participants were observed until July 1, 2022. The primary end points, including technical success and disease progression, and the secondary end points, including treatment parameters, complications, and tumor shrinkage during follow-up, were compared between the two groups, and multivariable regression was performed. Results After exclusion, 461 participants (mean age, 43 years ± 11 [SD]; 337 women) were included: 83 with and 378 without capsular invasion. After one participant with capsular invasion aborted MWA because of technical failure, 82 participants with and 378 participants without capsular invasion (mean tumor volume, 0.1 mL ± 0.1 vs 0.1 mL ± 0.1; P = .07) were analyzed with a mean follow-up period of 20 months ± 4 (range, 12-25 months) and 21 months ± 4 (range, 11-26 months), respectively. In those with and those without capsular invasion, comparable technical success rates were achieved (99% [82 of 83] vs 100% [378 of 378], P = .18), with one and 11 complications, respectively (1% [one of 82] vs 3% [11 of 378], P = .38). There was no evidence of differences in disease progression (2% [one of 82] vs 1% [four of 378]; P = .82) or tumor shrinkage (mean, 97% ± 8 [SD] vs 96% ± 13; P = .58). Conclusion Microwave ablation was feasible in the treatment of papillary thyroid microcarcinoma with US-detected capsular invasion and showed comparable short-term efficacy with or without the presence of capsular invasion. © RSNA, 2023 Clinical trial registration no. NCT04197960 Supplemental material is available for this article.

Risk factors and prediction models of lymph node metastasis in papillary thyroid carcinoma based on clinical and imaging characteristics

BACKGROUND

Papillary thyroid carcinoma (PTC) commonly presents with lymph node metastasis, which may be associated with worsened prognosis. This study aimed to comprehensively evaluate the risk factors of lymph node metastasis in PTC based on preoperative clinical and imaging data and to construct a nomogram model to predict the risk of lymph node metastasis.

METHODS

A total of 989 patients with PTC were enrolled and randomly divided into training and validation cohorts in an 8:2 ratio. Independent risk factors for lymph node metastasis in PTC were analyzed using univariate and stepwise multivariate logistic regression. An importance analysis of independent risk factors affecting lymph node metastasis was performed according to the random forest method. Subsequently, a nomogram to predict lymph node metastasis was constructed, and the predictive effect of the nomogram was evaluated using receiver operating characteristic analysis and calibration curves.

RESULTS

Univariate regression analysis revealed that age, sex, body weight, systolic blood pressure, free triiodothyronine, nodule location, nodule number, Thyroid Imaging Reporting and Data System (TI-RADS) grade on color Doppler ultrasound, enlarged lymph node present on imaging, and nodule diameter could affect lymph node metastasis in PTC. Stepwise multivariate regression analysis showed that sex, age, enlarged lymph node present on imaging, nodule diameter, and color Doppler TI-RADS grade were independent risk factors for lymph node metastasis in PTC. Combining these five independent risk factors, a nomogram prediction model was constructed. The area under the curve (AUC) of the nomogram in the training and validation cohorts was 0.742 and 0.765, respectively, with a well-fitted calibration curve.

CONCLUSION

Our study showed that independent risk factors for lymph node metastasis in PTC were sex, age, enlarged lymph node present on imaging, nodule diameter, and color Doppler TI-RADS grade. The nomogram constructed based on these independent risk factors can better predict the risk of lymph node metastasis.

Ultrasound-guided thermal ablation for papillary thyroid microcarcinoma: A systematic review

OBJECTIVE

Thyroidectomy is the first-line treatment for papillary thyroid microcarcinoma (PTMC), but often involves aggressive overtreatment. Thermal ablation (TA) has been gradually used for the treatment of recurrent PTMC. However, it is not recommended for the treatment of primary PTMC according to the Korean and Italian guidelines. Therefore, this systematic review aimed to analyse the indications, efficacy, and safety of TA in the treatment of PTMC.

DESIGN

Systematic review.

PATIENTS AND MEASUREMENTS

A search strategy was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. A total of 27 articles were included in this study until January 2022.

RESULTS

According to current guidelines and studies, we divided the indications of TA for PTMC into six primary and three secondary indications. Laser ablation (LA) has the advantages of a small needle, accurate output energy and precision ablation, and it is safe to important organs around the lesion. The patients recover quickly after radiofrequency ablation (RFA), with no major complications, recurrence, or lymph node metastasis. The volume reduction rate after RFA was the highest, followed by microwave ablation and LA, and the improvement in patient quality of life after TA was significantly better than after thyroidectomy.

CONCLUSIONS

TA is an effective alternative method for surgery in the treatment of low-risk PTMC and has the advantages of being minimally invasive, economical, having less bleeding and having a high postoperative quality of life.

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.

Surgical treatment of thyroid cancer: Established and novel approaches

Thyroid surgery is one of the most common head and neck procedures. The thyroid can be accessed through an anterior cervical incision, or by remote access techniques such as the transoral endoscopic thyroidectomy vestibular approach (TOETVA) which is favored for its ease, safety and direct plane to the thyroid gland. Other novel approaches for targeting small-localized well-differentiated thyroid cancer are by thermal ablation, namely ultrasound guided radiofrequency ablation. These innovative techniques for minimizing a cutaneous scar or for targeting small cancers directly without removal of the gland have developed alongside our realization that low risk well-differentiated thyroid cancer tends to be slow growing and indolent. Up to date, the most robust data supports offering these therapies primarily to patients who would be eligible for active surveillance protocols. In this paper, we review the traditional surgical approaches for removing well-differentiated thyroid cancer, as well as innovative remote access techniques (namely TOETVA), and minimally invasive thermal ablation (namely RFA).

Position paper from the Endocrine Task Force of the European Organisation for Research and Treatment of Cancer (EORTC) on the management and shared decision making in patients with low-risk micro papillary thyroid carcinoma

The incidence of differentiated thyroid cancer (DTC) has been increasing worldwide, mostly, as an increase in the incidental detection of micro papillary thyroid carcinomas (microPTCs), many of which are potentially overtreated, as suggested by the unchanged mortality. Several international guidelines have suggested a less aggressive approach. More recently, it has been shown that active surveillance or minimally invasive treatments (MIT) are good alternatives for the management of these patients. In this context, patient participation in the decision-making process is paramount. The Endocrine Task Force of the European Organisation for Research and Treatment of Cancer (EORTC) has undertaken the task to establish consensus and define its position based on the scientific evidence concerning, 1) the current state of diagnostic and management options in microPTCs, including the current opinion of physicians about shared decision making (SDM), 2) the available evidence concerning patients' needs and the available decision instruments, and 3) to provide practical suggestions for implementation of SDM in this context. To improve SDM and patients' participation, knowledge gaps and research directions were highlighted.

Differentiated thyroid carcinoma: An update

Differentiated thyroid carcinoma (DTC) is the most common endocrine cancer. Particularly the incidence of small clinically indolent tumors has been increasing significantly during the last decades because of increased diagnostic scrutiny, while the DTC-related mortality remained unchanged. In light of the increased awareness of the significant risk of detecting clinically indolent tumors and the potential harm and burden associated with overly diagnosis and the treatment, the approach towards management of DTC recently underwent a critical appraisal. The focus lays on reducing the unnecessary burden for patients with very low risk DTC and the correct identification of those who require treatment that is more intensive and/or follow-up. Management of DTC includes a range of different modalities, making multidisciplinary collaboration expedient. In this review, we elaborate on the recent developments in diagnosis, staging and management of DTC with specific focus on the more individualized risk assessment-based approach.

Efficacy, safety, and controversy of ultrasound-guided radiofrequency ablation in the treatment of T1N0M0 papillary thyroid carcinoma

Objective

To evaluate the safety effect, and controversy on the treatment outcomes of radiofrequency ablation (RFA) for T1N0M0 papillary thyroid carcinoma (PTC).

Materials and methods

This study is assessed the medical records of 142 patients with primary T1N0M0 PTC tumors after RFA between 2014 and 2022. 4 patients underwent delayed surgery (DS) after RFA and 411 T1N0M0 patients underwent DS were recorded. Outcomes were compared between RFA and DS groups after propensity score matching (PSM).

Results

The maximal diameter (MD) and volume (V) increased in months 1 (P < 0.01) and reduced after the 6-month follow-up (all P < 0.01). The disappearance and disease progression rates were 53.5% and 2.1%, respectively. The complication and disease progression rates had no significant difference between RFA and DS (P>0.05). In some cases, the tumors were not fully inactivated after RFA, and the central compartment lymph node (CCLN) were metastasis. The CCLN metastasis rate was 13.4%. MD, V and clustered calcifications were independent risk factors for CCLN metastasis by univariate analysis.

Conclusions

RFA is an effective and safe treatment option in selected patients with solitary T1N0M0 PTC. There are the risks of tumor incompletely ablated and CCLN metastasis.

Rigorous radiofrequency ablation can completely treat low-risk small papillary thyroid carcinoma without affecting subsequent surgical management

OBJECTIVE

Minimally invasive therapies are gaining interest because of the indolence and excellent prognosis of low-risk papillary thyroid carcinoma (PTC). This study aimed to evaluate the outcomes of radiofrequency ablation (RFA) for low-risk PTC and to determine the effects of ablation on subsequent surgical management.

METHODS

A medical record review was conducted including patients with low-risk PTC who underwent surgery after RFA from July 2015 to July 2021. Demographic characteristics, tumor characteristics, ablation procedures, surgical findings, and pathological changes were reviewed for all patients. The primary outcomes were surgical and pathological changes in post-ablation patients.

RESULTS

Of the 10 patients with 11 PTCs, 9 (90%) were women; the median (SD) patient age was 41.5 (8.2) years. The maximum diameter range of PTCs was 3.0-12.0 mm. All 10 patients underwent rigorous RFA procedure involving a four-step approach, and had received surgical management. Intraoperatively, no patients had muscle and nerve injuries, and mild adhesion of the post-ablation lesions with the anterior cervical muscle was observed in two cases. Histopathologically, no residual PTCs were observed in the ablated areas in all patients. Central lymph node metastasis (LNM) was found in three (30.0%, pN1a). Occult PTCs were observed in three cases (30.0%).

CONCLUSIONS

Our findings suggest that low-risk small PTCs can be completely treated with rigorous RFA, which does not affect subsequent surgical management, if necessary. RFA may be a treatment option, but occult PTCs and clinically negative LNMs may be overlooked. Long-term follow-up data are necessary to further identify its efficacy.

KEY POINTS

• RFA can completely treat low-risk small PTC. • RFA does not affect the subsequent surgical management if necessary. • Because occult PTCs and clinically negative LNMs may be overlooked by RFA, long-term follow-up data are necessary to further identify its efficacy.

A clinical study on microwave ablation of multifocal (≤ 3) T1N0M0 papillary thyroid carcinoma

OBJECTIVE

To evaluate the feasibility, efficiency, and safety of microwave ablation (MWA) for T1N0M0 multifocal (≤ 3) papillary thyroid carcinoma (PTC).

METHODS

This was a retrospective study, and patients who underwent MWA for multifocal (≤ 3) PTC were reviewed between October 2016 and December 2020. After ablation, the changes in tumor size and volume, as well as the rate of technical success, tumor disappearance, disease progression, and complications were assessed.

RESULTS

There were a total of 57 cases enrolled in the present study, which included 18 males and 39 females. The mean age was 44 ± 11 years (22-66 years); the mean follow-up time was 18 ± 11 months (6-48 months). Complete ablation was achieved in all enrolled cases. Therefore, the technical success rate was 100%. Due to expanding ablation, the MD and volume of the ablation zone, as well as the VRR, increased at the 1st and 3rd months after ablation and decreased at 12 and 18 months after ablation (p < 0.05 for all). The total complete tumor disappearance rate was 43.9% (25/57), including 54% (24/44) in the T1a subgroup vs. 7.7% (1/13) in the T1b subgroup (p = 0.003). The total disease progression rate was 7% (4/57), including 9.1% (4/44) in the T1a subgroup vs. 0% (0/13) in the T1b subgroup (p = 0.142). The overall complication rate was 5.3% (3/57), including 6.8% (4/44) in the T1a subgroup vs. 0% (0/13) in the T1b subgroup (p = 0.206).

CONCLUSION

This preliminary study indicates that MWA is a safe and effective treatment for T1N0M0 multifocal (≤ 3) PTC.

KEY POINTS

• MWA is a promising alternative method for T1N0M0 multifocal (≤ 3) PTC.

A systematic review and meta-analysis comparing tumor progression and complications between radiofrequency ablation and thyroidectomy for papillary thyroid carcinoma

BACKGROUND

Papillary thyroid cancer (PTC) is the most frequent thyroid cancers worldwide. The efficacy and acceptability of radiofrequency ablation (RFA) in the treatment of PTC have been intensively studied. The aim of this study is to focus on extra detailed that may influent for PTC or papillary thyroid microcarcinoma (PTMC).

MATERIALS AND METHODS

We identified a total of 1,987 records of a primary literature searched in PubMed, Embase, Cochrane Library, and Google Scholar by key words, from 2000 to 2022. The outcome of studies included complication, costs, and local tumor progression. After scrutiny screening and full-text assessment, six studies were included in the systematic review. Heterogeneity was estimated using I2, and the quality of evidence was assessed for each outcome using the GRADE guidelines.

RESULTS

Our review enrolled 1,708 patients reported in six articles in the final analysis. There were 397 men and 1,311 women in the analysis. Two of these studies involved PTC and four focused on PTMC. There were 859 patients in the RFA group and 849 patients in the thyroidectomy group. By contrast, the tumor progression of RFA group was as same as that surgical groups [odds ratio, 1.31; 95% CI, 0.52-3.29; heterogeneity (I2 statistic), 0%, p = 0.85]. The risk of complication rates was significantly lower in the RFA group than that in the surgical group [odds ratio, 0.18; 95% CI, 0.09-0.35; heterogeneity (I2 statistic), 40%, p = 0.14].

CONCLUSIONS

RFA is a safe procedure with a certain outcome for PTC. RFA can achieve a good efficacy and has a lower risk of major complications.

Thermal ablation for papillary thyroid microcarcinoma: Some clarity amid controversies

The increasing incidence of papillary thyroid microcarcinoma (PTMC) has become a global challenge. Because of its indolent nature, active surveillance (AS) has been proposed as a treatment option in selected PTMC patients to prevent surgery-related complications. However, only a few patients with PTMC receive the AS approach because of the serious psychological burden following the "cancer" diagnosis and the uncertainty of the timing for metastatic dissemination. Ultrasound (US)-guided thermal ablation can bridge the gap in the treatment options of PTMC patients who wish for a minimally invasive management approach. However, it has acquired only marginal attention from the thyroid guideline societies because of concerns regarding incomplete elimination. The recently published guidelines from the European Thyroid Association-Cardiovascular and Interventional Radiological Society of Europe and the American Head Neck Society Endocrine Section -initiated global consensus provide the most definitive evidence and essential foundational experience to address the long-term controversy over US-guided thermal ablation for low-risk PTMC patient management and facilitate the responsible global dissemination of minimally invasive strategies.