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.

A Preliminary Study on the Microwave Ablation of Multifocal Papillary Thyroid Microcarcinoma.

RATIONALE AND OBJECTIVES: To evaluate the feasibility, efficiency, and safety of microwave ablation (MWA) for multifocal papillary thyroid microcarcinoma (PTMC). METHODS: This was a retrospective study, and the data of patients who underwent MWA for multifocal PTMC from October 2016 to December 2021 were reviewed. After ablation, the changes in tumor size and volume, as well as the rates of technical success, tumor disappearance, disease progression, and complications, were assessed. According to the tumor location, the cases were further divided into a unilateral multifocal disease (UMD) subgroup and a bilateral multifocal disease (BMD) subgroup. Further analyses were carried out. RESULTS: There was a total of 94 cases enrolled in the present study, which included 24 males and 70 females. The median age was 40 years (22-66 years); the median follow-up time was 14 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 increased at the 1st and 3rd months after ablation and decreased from the 12th month after ablation (p < 0.05 for all). The total complete tumor disappearance rates were 45/94 (47.87%) overall, 40.625% (13/32) in the UMD subgroup and 51.61% (32/62) in the BMD subgroup (p = 0.312). The total disease progression rates were 4.26% (4/94) overall, 6.25% (2/32) in the UMD subgroup and 3.23% (2/62) in the BMD subgroup (p = 0.881). The overall complication rate was 4.26% (4/94). CONCLUSION: This preliminary study indicates that MWA is a safe and effective treatment for multifocal PTMC.

A comparative study of quality of life in patients with papillary thyroid carcinoma undergoing microwave ablation vs. Total thyroidectomy.

OBJECTIVE: To compare the health-related quality of life (HRQoL) of patients with T1N0M0 papillary thyroid carcinoma (PTC) who underwent microwave ablation (MWA) and those who underwent total thyroidectomy (TT). MATERIALS AND METHODS: From February 2018 to February 2022, 180 T1N0M0 PTC patients were enrolled in present study, including 90 in the MWA group and 90 in the TT group, respectively. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) and Thyroid Cancer-Specific Quality of Life Questionnaire (THYCA-QoL) were completed by patients to evaluate their HRQoL scores. RESULTS: According to the results of the EORTC-QLQ-C30, there was a significant difference in the scores of global health, physical, emotional, etc. between the two groups, which indicated that the quality of life in these items in the MWA group was better than those in the TT group (all p < 0.05). According to the results of the THYCA-QoL, all items had significant differences between the two groups except for headache, which demonstrated the thyroid-specific quality of life was higher in the MWA group than in the TT group (all p < 0.05). CONCLUSION: Ultrasound (US)-guided MWA offers a significant advantage in HRQoL over TT in T1N0M0 PTC patients, which provides an important reference for MWA as an alternative strategy to TT.

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.

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

OBJECTIVES: To study the efficacy and safety of an improved hydrodissection protocol based on the perithyroidal fascial space during microwave ablation for papillary thyroid carcinoma (PTC). METHODS: The data of 341 patients (94 men and 247 women, median age 41 years old, 25%-75% interquartile range 34-53 years old, nodule maximum diameter 0.2-1.9 cm) who underwent microwave ablation for PTC were retrospectively reviewed. Among them, 185 patients underwent traditional hydrodissection and served as a control group, and 156 patients underwent improved hydrodissection based on perithyroidal fascial spaces, constituting the improved group. Improvements in safety were analyzed by comparing complications between the two groups. The characteristics of hydrodissected spaces, complications, and follow-up results were recorded. RESULTS: Hydrodissection was successfully performed in all enrolled patients according to the protocol. The incidence of hoarseness caused by recurrent laryngeal nerve injury, the most common complication in thermal ablation of thyroid nodules, was significantly lower in the improved group than in the control group (1.9% vs. 8.1%, p = 0.021). The median hoarseness recovery time in the improved group was shorter than that in the control group (2 months vs. 3 months, p = 0.032). During follow-up, no local recurrence was encountered in either group. The tumor disappearance rate was not significantly different between the two groups (69.9% vs. 75.7%, p = 0.228). CONCLUSIONS: Improved hydrodissection based on perithyroidal fascial spaces had better protective effects than traditional hydrodissection.

Preliminary Study of Microwave Ablation for Multifocal Papillary Thyroid Microcarcinoma in Nonoperative Candidates.

PURPOSE: To study the feasibility, safety, and effectiveness of microwave ablation (MWA) in patients with multifocal papillary thyroid microcarcinoma (PTMC). MATERIALS AND METHODS: This retrospective study included patients who underwent MWA for multifocal PTMC (number of nodules ≤3). A total of 44 patients were included, and the mean age was 43 years (SD ± 11). After ablation, progression-free survival (PFS) at 6, 12, 24, 36, and 48 months; disease progression; change in tumor size and volume; tumor disappearance rate; and adverse events (AEs) were assessed, and the feasibility, safety, and effectiveness of MWA for PTMC were evaluated on the basis of statistical analysis. RESULTS: The median follow-up period was 18 months (interquartile range, 12-33 months). The PFS rates at 6, 12, 24, 36, and 48 months were 100.0%, 96.4%, 96.4%, 70.3%, and 52.7%, respectively. The disease progression rate was 11.4% (5 of 44 patients). The maximum diameter (MD) and volume of the ablation zone were larger at the 3-month follow-up than before ablation (median MD, 13.0 vs 7.0 mm; P < .001; median volume, 503.8 vs 113.0 mm3; P < .001). Subsequently, the tumors exhibited a reduction in both size and volume after 18 months (median MD, 4.0 vs 7.0 mm; P = .04; median volume, 12.6 vs 113.0 mm3; P = .055). At the end of the follow-up period, the complete response rate was 59% (26 of 44 patients). The overall AE rate was 6.8%. CONCLUSIONS: MWA is a feasible treatment for PTMC (number of nodules ≤3), and this study preliminarily demonstrated the safety and effectiveness of this technique.

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.

Changes in Thyroid Antibodies after Microwave Ablation of Thyroid Nodules.

Purpose: Microwave ablation (MWA) is a minimally invasive method for the thermal ablation of benign thyroid nodules and papillary thyroid cancer (PTC) and has shown promising results. The aim of this study was to investigate the impact of MWA on thyroid antibodies and associated influencing factors. Materials and Methods: A total of 119 patients, including 69 with benign thyroid nodules and 50 with PTC, underwent MWA between June 2019 and June 2021. The serum levels of (free) triiodothyronine, (free) thyroxine, thyrotropin, and antibodies against Tg (TGAb), thyrotropin receptors (TRAb), and thyroid peroxidase (TPOAb) were measured during the follow up. Results: One month after ablation, three patients (4.3%) in the benign group had hypothyroidism, and one (1.4%) had hyperthyroidism. Four patients (5.8%) had subclinical hypothyroidism, and two (2.9%) had subclinical hyperthyroidism. Among the PTC patients, two (4%) had hypothyroidism, and one (2%) had hyperthyroidism. Two patients (4%) had subclinical hypothyroidism, and one (2%) had subclinical hyperthyroidism. In the benign group, among patients with normal preablation antibodies, the postablation TGAb abnormal rate was 12.7%, the TPOAb level was 4.8%, and the TRAb level was 0%. Among PTC patients, the postablation TGAb abnormal rate was 11.4%, the TPOAb level was 8.7%, and the TRAb level was 4.0%. The cutoff value of preablation TGAb for predicting postoperative antibody abnormalities was 19.0 IU/mL, while that of TPOAb was 11.4 IU/mL. Conclusions: MWA of thyroid nodules had little influence on thyroid function and antibodies. Elevations in TGAb, TPOAb, and TRAb beyond the normal ranges after MWA may be related to high preablation levels of TGAb and TPOAb.

Recurrent Laryngeal Nerve Injury in Thermal Ablation of Thyroid Nodules-Risk Factors and Cause Analysis.

CONTEXT: Recurrent laryngeal nerve (RLN) injury is a complication of thermal thyroid nodule treatment. OBJECTIVE: We investigated the influencing factors of RLN injury in patients who underwent thermal ablation of thyroid nodules. METHODS: The data of 1004 patients (252 male, 752 female; median age 44 years) who underwent thermal thyroid nodule ablation were retrospectively reviewed. Patients were divided into benign cystic, benign solid, and papillary thyroid cancer (PTC) groups. The parameters related to RLN injury were analyzed, including the largest diameter, location of the nodules, and shortest distance of the nodule to thyroid capsule and tracheoesophageal groove (TEG). Univariate and multivariate analyses were performed to select risk factors for RLN injury. RESULTS: The RLN injury rate was higher in PTC (6.3%) than in benign cystic (1.2%, P = 0.019) and solid nodules (2.9%, P = 0.018). PTC subgroup analysis showed that the RLN injury rate was higher in T1b (10.7%) and T2 (28.6%) PTC than in T1a PTC (5.0%, P < 0.05). In the PTC group, TEG distance, anterior capsule distance, median capsule distance, posterior capsule distance, and maximum nodule diameter were risk factors for RLN injury. The logistic regression fitting of the nomogram showed high prediction efficiency (C-Index 0.876). The main cause of RLN injury was insufficient medial isolating fluid (MIF). The safety thicknesses of MIF for benign cystic, benign solid, and PTC nodules were 3.1 mm, 3.7 mm, and 3.9 mm, respectively. CONCLUSION: Several risk factors for RLN injury should be considered before thermal ablation of thyroid nodules. The RLN injury rate could be predicted with the nomogram.

A preliminary study of microwave ablation for solitary T1N0M0 papillary thyroid carcinoma with capsular invasion.

OBJECTIVE: To evaluate the feasibility, efficiency, and safety of microwave ablation (MWA) for T1N0M0 papillary thyroid carcinoma (PTC) with capsular invasion (CI). METHODS: The data of 69 T1N0M0 PTC with CI underwent MWA from August 2015 to January 2020 were retrospectively analyzed. All PTC nodules were pathologically confirmed by fine needle aspiration (FNA). The extended ablation was performed in all cases, that is, the ablation zone completely covered the tumor and extended the tumor edge by at least 2 mm. The strategy of fluid isolation was successfully applied before and during ablation. The strategy of multiple point ablation was applied. After ablation, the changes in tumor size at different time points, local recurrence, new lesions, lymph node metastasis (LNM), and complications were evaluated and recorded. The technical feasibility, technical success rate, and safety were analyzed. RESULTS: Based on the contrast-enhanced ultrasound results, complete ablation has been achieved in all enrolled cases after ablation. The mean maximum tumor diameter and the mean volume of PTC nodules before ablation were 0.84 ± 0.39 cm (range, 0.3-2 cm) and 0.26 ± 0.35 ml (range, 0.01-1.72 ml) respectively. The mean follow-up time was 26 ± 10 months (range, 9-48 months). Nodules in 47 cases (68.1%) completely disappeared in the follow-up period. No local recurrence was detected. The incidence of new lesions and LNM was 4.3% (3/69) and 4.3% (3/69) respectively. Further ablations have been successfully employed for all of the new lesions and LMN. Light voice changes (2.9%, 2/69) were the only major complication, which was relieved within 6 months after MWA. The sizes of the ablation zone increased firstly within 6 months after MWA compared with the pretreatment tumor size (p < 0.05). Twelve months later, the sizes were smaller than those before MWA (p < 0.05 for all). CONCLUSIONS: MWA is an effective, safe, and feasible method in treating T1N0M0 PTC with CI.