Microwave Ablation versus Surgical Resection for US-detected Multifocal T1N0M0 Papillary Thyroid Carcinoma: A 10-Center Study.

Background Microwave ablation (MWA) is currently under preliminary investigation for the treatment of multifocal papillary thyroid carcinoma (PTC) and has shown promising treatment efficacy. Compared with surgical resection (SR), MWA is minimally invasive and could preserve thyroid function. However, a comparative analysis between MWA and SR is warranted to draw definitive conclusions. Purpose To compare MWA and SR for preoperative US-detected T1N0M0 multifocal PTC in terms of overall and 1-, 3-, and 5-year progression-free survival rates and complication rates. Materials and Methods In this retrospective study, 775 patients with preoperative US-detected T1N0M0 multifocal PTC treated with MWA or SR across 10 centers between May 2015 and December 2021 were included. Propensity score matching (PSM) was performed for patients in the MWA and SR groups, followed by comparisons between the two groups. The primary outcomes were overall and 1-, 3-, and 5-year progression-free survival (PFS) rates and complication rates. Results After PSM, 229 patients (median age, 44 years [IQR 36.5-50.5 years]; 179 female) in the MWA group and 453 patients (median age, 45 years [IQR 37-53 years]; 367 female) in the SR group were observed for a median of 20 months (range, 12-74 months) and 26 months (range, 12-64 months), respectively. MWA resulted in less blood loss, shorter incision length, and shorter procedure and hospitalization durations (all P < .001). There was no evidence of differences in overall and 1-, 3-, or 5-year PFS rates (all P > .05) between MWA and SR (5-year rate, 77.2% vs 83.1%; P = .36) groups. Permanent hoarseness (2.2%, P = .05) and hypoparathyroidism (4.0%, P = .005) were encountered only in the SR group. Conclusion There was no evidence of a significant difference in PFS rates between MWA and SR for US-detected multifocal T1N0M0 PTC, and MWA resulted in fewer complications. Therefore, MWA is a feasible option for selected patients with multifocal T1N0M0 PTC. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Georgiades in this issue.

Ultrasound-guided microwave ablation versus surgery for solitary T1bN0M0 papillary thyroid carcinoma: a prospective multicenter study.

OBJECTIVE: Microwave ablation (MWA) has emerged as a minimally invasive technology for papillary thyroid microcarcinoma (PTMC), but it has not been widely applied to treat T1bN0M0 PTC with high-level evidence. This study was designed to compare the real-world efficacy and safety of MWA or surgery for treating T1bN0M0 PTC. METHODS: From December 2019 to April 2021, 123 continuous unifocal T1bN0M0 PTC patients without lymph node metastasis (LNM) or distant metastasis (DM) were included from 10 hospitals. Patients were allocated into the MWA or surgery group based on their willingness. The main outcomes were local tumour progression (LTP), new thyroid cancer, LNM, and DM. The secondary outcomes included changes in tumour size and volume, complications, and cosmetic results. Subgroup analyses were conducted to identify influencing factors. RESULTS: Fifty-two patients chose MWA, and 71 patients chose surgery. Patients had similar demographic information and tumour characteristics in the two groups. The follow-up durations after MWA and surgery were 10.6 ± 4.2 and 10.4 ± 3.4 months, respectively. The LNM rate was 5.8% in the MWA group and 1.4% in the surgery group (p = 0.177). No LTP, new thyroid cancer, or distant metastasis (DM) occurred in either group. Five (9.6%) of the 52 patients in the MWA group and 8 (11.3%) of the 71 patients in the surgery group had complications (p = 0.27). Better cosmetic results were found in the MWA group (p < 0.01). CONCLUSION: MWA achieved comparable short-term treatment efficacy with surgery. MWA might be an optional choice for surgery for low-risk T1bN0M0 PTC but concerns about LNM need to be studied further. CLINICAL RELEVANCE STATEMENT: MWA achieved comparable short-time treatment efficacy with surgery. MWA might be an optional choice for surgery for low-risk T1bN0M0 PTC. KEY POINTS: • MWA achieved comparable short-term treatment efficacy with surgery. MWA might be an optional choice for surgery for low-risk T1bN0M0 PTC but concerns about LNM need to be studied further. • The complication rate in the surgery group was higher than that in the MWA group without a significant difference. • There was no statistically significant difference in the LNM rate between the MWA and surgery groups.

Efficacy and safety of microwave ablation for the treatment of multifocal versus unifocal T1N0M0 papillary thyroid carcinoma: a propensity-matched multicentre retrospective study.

OBJECTIVES: Microwave ablation (MWA) has been widely used for unifocal papillary thyroid carcinoma (U-PTC) and has recently been preliminarily used in multifocal papillary thyroid carcinoma (M-PTC). However, the efficacy and safety of MWA for M-PTC have not been investigated in large samples. The aim of the present study was to evaluate the efficacy and safety of MWA for M-PTC and compare them with MWA for U-PTC. MATERIALS AND METHODS: This retrospective multicentre study enrolled 504 patients (376 females) who underwent MWA for U-PTC (340 cases) or M-PTC (164 cases) from Jan 2015 to Dec 2020. The median age of the patients was 43 years (age range, 20-80 years). Propensity score matching (PSM) was used to balance the baseline characteristics between M-PTC group and U-PTC group. The tumour progression, tumour disappearance, and complication rates were compared between the two groups. RESULTS: The complete ablation was achieved in all enrolled cases in one session. According to the statistical results, no significant differences were shown in tumour progression-free survival (p  = 0.29) or cumulative tumour progression rate (6.7% vs. 4.3%, p  = 0.33) between the M-PTC and U-PTC groups during the follow-up time. However, the tumour disappearance rate in the M-PTC group was lower in the U-PTC group (40.9% vs. 62.8%, p < 0.001), and tumour disappearance was slower in the M-PTC group (p < 0.001). The complication rate showed no significant difference (3.0% vs. 4.9%, p  = 0.571). CONCLUSIONS: MWA is an effective and safe treatment for selected patients with M-PTC, and the prognosis is similar to that of U-PTC. CLINICAL RELEVANCE STATEMENT: The present study provided evidence that compared with unifocal papillary thyroid cancer, microwave ablation could also treat multifocal T1N0M0 papillary thyroid cancer safely with similar clinical outcome, which could promote the application of minimally invasive treatment for papillary thyroid cancer. KEY RESULTS: • Microwave ablation for multifocal and unifocal T1N0M0 papillary thyroid carcinoma had similar tumour progression rates after propensity score matching (6.7% vs. 4.3%, p = 0.33). • The tumour disappearance rate in the multifocal group was lower than that in the unifocal group (40.9% vs. 62.8%, p < 0.001), and tumour disappearance was slower in the multifocal group (p < 0.001). • Tumour size, number, and location were not risk factors for tumour progression in the multifocal papillary thyroid cancer group.

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.

Multimodality US versus Thyroid Imaging Reporting and Data System Criteria in Recommending Fine-Needle Aspiration of Thyroid Nodules.

Background Current guidelines recommend the use of conventional US for risk stratification and management of thyroid nodules. However, fine-needle aspiration (FNA) is often recommended in benign nodules. Purpose To compare the diagnostic performance of multimodality US (including conventional US, strain elastography, and contrast-enhanced US [CEUS]) with the American College of Radiology Thyroid Imaging Reporting and Data System (TI-RADS) in the recommendation of FNA for thyroid nodules to reduce unnecessary biopsies. Materials and Methods In this prospective study, 445 consecutive participants with thyroid nodules from nine tertiary referral hospitals were recruited between October 2020 and May 2021. With univariable and multivariable logistic regression, the prediction models incorporating sonographic features, evaluated with interobserver agreement, were constructed and internally validated with bootstrap resampling technique. In addition, discrimination, calibration, and decision curve analysis were performed. Results A total of 434 thyroid nodules confirmed at pathologic analysis (259 malignant thyroid nodules) in 434 participants (mean age, 45 years ± 12 [SD]; 307 female participants) were included. Four multivariable models incorporated participant age, nodule features at US (proportion of cystic components, echogenicity, margin, shape, punctate echogenic foci), elastography features (stiffness), and CEUS features (blood volume). In recommending FNA in thyroid nodules, the highest area under the receiver operating characteristic curve (AUC) was 0.85 (95% CI: 0.81, 0.89) for the multimodality US model, and the lowest AUC was 0.63 (95% CI: 0.59, 0.68) for TI-RADS (P < .001). At the 50% risk threshold, 31% (95% CI: 26, 38) of FNA procedures could be avoided with multimodality US compared with 15% (95% CI: 12, 19) with TI-RADS (P < .001). Conclusion Multimodality US had better performance in recommending FNA to avoid unnecessary biopsies than the TI-RADS. Clinical trial registration no. NCT04574258 © RSNA, 2023 Supplemental material is available for this article.

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.

Microwave ablation vs. surgery for papillary thyroid carcinoma with minimal sonographic extrathyroid extension: a multicentre prospective study.

OBJECTIVES: Minimal extrathyroid extension (mETE) was removed from the TNM staging system. This study was designed prospectively to compare the safety and efficacy of microwave ablation (MWA) versus surgery for treating T1N0M0 papillary thyroid carcinomas (PTC) with sonographically detected mETE. METHODS: From December 2019 to April 2021, 198 patients with T1N0M0 mETE-PTCs evaluated by preoperative ultrasound from 10 hospitals were included. Ninety-two patients elected MWA, and 106 patients elected surgery for treatment. MWA was performed using extensive ablation with hydrodissection. Surgery consisted of lobectomy with ipsilateral central lymph node dissection (CLD), lobe and isthmus excision with ipsilateral CLD and total thyroidectomy with ipsilateral CLD. The rates of technical success, cost, oncologic outcomes, complications and quality of life of the two groups were assessed. RESULTS: The follow-up times for the MWA and surgery groups were 12.7 ± 4.1 and 12.6 ± 5.0 months, respectively. The technical success rate was 100% for both groups. Oncological outcomes of the two groups were similar during the follow-up (all p > 0.05). The MWA group had a shorter operation time, less blood loss and lower costs (all p < 0.001). Three complications (3.3%) were reported in the MWA group and 4 (3.8%) in the surgery group (p = 0.846). The surgery group had higher scores for scar problems and anxiety (p < 0.001 and p = 0.003, respectively). CONCLUSIONS: Microwave ablation was comparable in the short term to surgery in terms of treatment safety and efficacy in selected patients with T1N0M0 mETE-PTC detected by ultrasound. KEY POINTS: • Microwave ablation is comparable to surgery in the safety and short-term efficacy for PTCs with sonographically detected mETE. • Thermal ablation is technically feasible for mETE-PTC treatment. • Patients with mETE-PTC have similar quality of life in the two groups, except for worse scar problems and anxiety in the surgery group.

Ultrasound-guided thermal ablation for papillary thyroid microcarcinoma: a multicenter retrospective study.

PURPOSE: Ultrasound-guided thermal ablation (including microwave ablation [MWA] and radiofrequency ablation [RFA]) has emerged as a remarkable technology for the treatment of benign and malignant diseases. The objective of this multicenter study was to assess the efficacy and safety of thermal ablation in a large cohort of patients with papillary thyroid microcarcinoma (PTMC). MATERIALS AND METHODS: Retrospective study of 725 patients who underwent MWA/RFA at 11 centers between March 2015 and March 2020. The mean age of patients was 46 ± 11 years (range, 22-81); the mean follow-up time was 21 ± 13 months (range, 6-60). Changes in size of tumor, the rates of tumor disappearance, disease progression, and complications were assessed. RESULTS: From 6 months post-ablation, the size of tumors was significantly reduced compared with those recorded pre-ablation (p < 0.001 for all). Five hundred and fifteen (71.0%) PTMCs had completely disappeared as assessed by ultrasound examination. Six (0.8%) patients developed disease progression post-ablation; of these, 5 (0.7%) patients developed new PTMCs, while one (0.1%) patient developed cervical lymph node metastasis. Nineteen (2.6%) patients developed complications post-ablation; of these 14 (1.9%) patients developed voice hoarseness, 4 (0.6%) developed hematoma, and one (0.1%) patient developed cough. CONCLUSIONS: Ultrasound-guided thermal ablation represents an effective and safe treatment for patients with PTMC besides active surveillance and surgery.

Efficacy and Safety of Thermal Ablation for Treatment of Solitary T1N0M0 Papillary Thyroid Carcinoma: A Multicenter Retrospective Study.

Background Microwave ablation (MWA) and radiofrequency ablation (RFA) have recently attracted interest as minimally invasive treatment modalities for papillary thyroid carcinoma (PTC). However, the ablation outcomes of T1N0M0 PTC are not well characterized. Purpose To evaluate the efficacy and safety of thermal ablation (MWA or RFA) of solitary T1N0M0 PTC in patients who were ineligible for (due to presence of comorbid cardiovascular disease, renal failure, other malignancy, etc) or who refused surgery. Materials and Methods This was a retrospective multicenter study of 847 patients (660 women) who underwent thermal ablation for PTC (673 T1a, 174 T1b) between March 2015 and March 2020; of these patients, 645 underwent MWA and 202 underwent RFA. The mean age of patients was 46 years ± 11 (standard deviation) (age range, 18-81 years); the mean follow-up time was 22 months ± 13 (range, 6-60 months). Changes in tumor size and volume and the rates of technical success, tumor disappearance, disease progression, and complications were assessed. Results The technical success rate was 100%. Relative to preablation measurements, the maximum diameter and volume of the ablation zone increased during the 1st month after ablation (P < .001), whereas there was no difference by the 3rd month; subsequently, the tumors showed reduction in size at 6, 9, and 12 months (all P < .001). Complete disappearance of tumors occurred in 68% of patients (577 of 847; 69% [466 of 673] in the T1a group vs 64% [111 of 174] in the T1b group; P < .001). The postablation disease progression rate was 1.1% (nine of 847 patients; 0.9% [six of 673 patients] in the T1a group vs 1.7% [three of 174 patients] in the T1b group; P = .54). The overall complication rate was 3.4% (29 of 847 patients; 2.7% [18 of 673 patients] in the T1a group vs 6.3% [11 of 174 patients] in the T1b group; P = .02). Conclusion This multicenter study provided evidence that thermal ablation is an effective and safe treatment option in selected -patients with solitary T1N0M0 papillary thyroid carcinoma. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Baek and Cho in this issue.