Efficacy and safety of thermal ablation in papillary thyroid carcinoma with sonographic tracheal adhesions: a preliminary analysis

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. 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. 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%). 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. 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.

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.

Ultrasound‑guided Percutaneous Radiofrequency and Microwave Ablation for Cervical Lymph Node Metastasis from Papillary Thyroid Carcinoma: A Systematic Review and Meta‑analysis of Clinical Efficacy and Safety.

This study aimed to evaluate the efficacy and safety of thermal ablation in the treatment of patients with Bethesda IV thyroid nodules (follicular neoplasms) by analyzing large-scale data on various outcomes. Literature searches were conducted in PUBMED, EMBASE, Web of Science, and the Cochrane Library for studies on the use of thermal ablation in patients with Bethesda IV thyroid nodules published from March 1, 2014, to March 1, 2024. Data on volume change at 12 months; the volume reduction rate (VRR) at 1, 3, 6, and 12 months; the complete disappearance rate (CDR); and the complication rate were evaluated. All the data were analyzed with STATA 15. Five eligible studies were included. The findings indicate that thermal ablation is both effective and safe. The mean change in tumor volume at 12 months postthermal ablation was characterized by a standardized mean difference (SMD) of -1.13 (95% CI: -1.36 - -0.90, p = 0.000). Specifically, the mean changes in tumor volume at 12 months after radiofrequency ablation (RFA) and microwave ablation (MWA) were - 1.19 (95% CI: -1.75 - -0.64) and - 1.26 (95% CI: -1.71 - -0.81), respectively. The VRRs at 1, 3, 6, and 12 months postthermal ablation were 43% (95% CI: 33 - 53%), 47% (95% CI: 20 - 74%), 69% (95% CI: 62 - 76%), and 85% (95% CI: 79 - 90%), respectively. The VRRs at 12 months after RFA and MWA were 84% (95% CI: 76 - 91%) and 85% (95% CI: 75 - 95%), respectively. The VRR at 12 months, stratified by initial nodule size, was 84% (95% CI: 77 - 91%) and 86% (95% CI: 78 - 94%). The CDR at the final follow-up was 88% (95% CI: 80 - 95%). The complication rate was 4.0% (95% CI: 0.0 - 8.0%), with pain and hoarseness being the most frequently reported complications; no life-threatening complications were documented. Thermal ablation is a reliable treatment for Bethesda IV thyroid nodules, and RFA and MWA are advantageous treatment strategies. However, more prospective, multicenter, and large-sample studies are needed in the future.

Comparative Efficacy and Safety of Ultrasound-Guided Thermal Ablation for Benign Thyroid Nodules versus Low-Risk Follicular Neoplasms: A Single-Center Retrospective Study.

BackgroundTo evaluate the safety and efficacy of radiofrequency ablation (RFA), microwave ablation (MWA), and laser ablation (LA) for the treatment of cervical metastatic lymph nodes (CMLNs) of papillary thyroid carcinoma (PTC).MethodsThe Pubmed, EMBASE, Web of Science, and Cochrane Library databases were searched for studies on the safety and efficacy of thermal ablations (RFA, MWA, and LA) for the treatment of CMLNs of PTC until March 30, 2022. A review of 334 potential papers identified 17 eligible papers including 312 patients. Fixed-effects model or random-effects model was used to evaluate the pooled proportions of volume reduction rate (VRR), complete disappearance, and recurrence, and pooled estimates of changes in the largest diameter, volume, and serum Tg after ablation. The pooled proportions of overall and major complications were calculated. Subgroup analysis based on treatment modalities. The heterogeneity among studies was analyzed by using Q statistics and inconsistency index I2. MINORS scale was used to evaluate the quality of the studies.Results17 eligible studies were finally identified, including 312 patients and 559 CMLNs. The pooled proportions of VRR, complete disappearance and recurrence of CMLNs were 91.28% [95% confidence interval (CI): 86.60-95.97%], 67.9% [95% CI: 53.1-81.1%] and 7.8% [95%CI: 3.0-14.1%], respectively. The pooled estimates of changes in the largest diameter, volume and serum Tg were 8.12 mm [95%CI: 6.78-9.46 mm], 338.75 mm3 [95%CI: 206.85 -470.65 mm3] and 5.96 ng/ml [95%CI: 3.68-8.24 ng/ml], respectively. The pooled proportions of overall and major complications were 2.9% [95%CI: 0.3-7.1%] and 0.3% [95%CI: 0-1.9%], respectively. Significant between-study heterogeneity was observed for complete disappearance (P<0.01, I2 =88.6%), VRR (P<0.001, I2 =99.9%), recurrence (P=0.02, I2 =47.76%), overall complications (P<0.02, I2 =44.8%), and changes in the largest diameter (P < 0.001, I2 =82.6%), volume (P<0.001, I2 =97.0%), and serum Tg (P < 0.001, I2 =93.7%). Subgroup analysis showed heterogeneity of the VRR among the treatment modality (I2 range: 84.4-100%). The VRR of MWA was the highest (97.97%), followed by RFA (95.57%) and LA (84.46%) (P < 0.001).ConclusionAll thermal ablations were safe and effective for the treatment of CMLNs of PTC. However, each treatment had significant heterogeneity in VRR. Compared with RFA and MWA, LA was less effective in reducing the volume of CMLNs of PTC.

To evaluate the efficacy and safety of thermal ablation in treating solitary low-risk T2N0M0 papillary thyroid cancer (PTC) and compare the outcomes of microwave ablation (MWA) and radiofrequency ablation (RFA). This retrospective, single center study involved 34 patients (age: 40.0 ± 13.9 years; 28 female) who had low-risk T2N0M0 PTC with a maximum diameter >2 cm and ≤4 cm and underwent MWA (n = 15) or RFA (n = 19) from November 2016 to April 2023. The primary outcomes were the cumulative rate of disease progression and delayed surgery rates. In contrast, the secondary outcomes included changes in tumor size, cumulative rate of complete tumor disappearance, and complication rates. The median follow-up period was 18.0 months (interquartile range [IQR]: 9.0-40.0 months). At 12 months, the median volume reduction rate of the ablation zone was 74.2% (IQR: 53.7%-86.0%). Disease progression was noted in two patients within 1 year, including one patient with local tumor progression post-RFA and one with a new tumor post-MWA, resulting in a constant cumulative disease progression rate of 8.8% (95% confidence interval [CI]: 0%-19.8%) throughout the remaining follow-up period. Both patients were subsequently treated with additional ablation and did not require surgery. The cumulative rates of complete tumor disappearance at 1, 3, and 5 years were 4.0% (95% CI: 0%-11.4%), 26.8% (95% CI: 2.7%-44.9%), and 51.2% (95% CI: 0%-79.1%), respectively. No significant differences were observed in the disease progression (P = 0.829) or complete tumor disappearance (P = 0.633) rates between the MWA and RFA groups. Complications occurred in 14.7% (5/34) of patients presenting with transient hoarseness. RFA had a higher but not statistically significant complication rate than MWA did (21.1% [4/19] vs. 6.7% [1/15]; P = 0.355). Both MWA and RFA demonstrated promising short-term outcomes in terms of efficacy and safety in treating solitary low-risk T2N0M0 PTC, with no significant differences.

Comparative Long-term Outcomes of RFA vs. MWA for T1N0M0 Papillary Thyroid Carcinoma in the Danger Triangle: ADual-Center Retrospective Study.

BackgroundTo compare the two ablation techniques, we assessed 81 benign thyroid nodules of 38 cases who underwent radio frequency ablation (RFA) and 43 cases who underwent microwave ablation (MWA) over a 12-month period. The inclusion criteria involved benign thyroid nodules with compression symptoms or cosmetic problems, cytological confirmation of benignity with no atypical cells, and case refusal or unfit for operation. No predilection for the ultrasound nature of the nodules, whether they were cystic, solid, or complex, or their size or number. Radio frequency ablation was carried out utilizing the Mygen (M-3004) radio frequency generator from RF Medical Co., Ltd., South Korea, and microwave ablation (MWA) was conducted utilizing the Canyon KY2000-A MCW generator from Canyon Medical Inc. The clinical problems and the nodules volume have been assessed both following and prior to the surgery. Factors and complications associated with volume reduction rate (VRR) have been assessed. This investigation is designed to evaluate the efficacy and safety of microwave ablation guided by ultrasound (US) versus radio frequency ablation in the management of benign thyroid nodules. ResultsMean volume reduction rate (VRR) of MWA group versus the RFA group at one, three, six, and twelve months were 53.1% ± 11.2% versus 45.8% ± 13.5% (P = 0.009), 67.9% ± 11.5% versus 61.8% ± 12.8% (P = 0.027), 77.5% ± 9.7% versus 73.4% ± 11% (P = 0.084), and 85.4% ± 7.6% versus 83.6% ± 6.4% (P-value = 0.252), respectively. A statistically significant variance has been discovered within the VRR among both the radio frequency ablation group and the microwave ablation group in one- and three-month follow-up. Additionally, all cases were able to maintain thyroid function, and both groups reported a significant reduction in symptom and cosmetic scores. Among the overall case population, one patient in the RF group had a minor burn that resolved after 1 month, and transient voice changes occurred in one patient in each group that resolved after two weeks.ConclusionsBoth radio frequency ablation and microwave ablation are safe and efficient methods for managing BTNs. The MWA group showed greater volume reduction rates at the 1- and 3-month follow-ups.

The comparative efficacy of single-session radiofrequency ablation (RFA) versus microwave ablation (MWA) for benign solid thyroid nodules remains unclear because existing literature consists of heterogenous baseline and wide range of nodule volumes. This study identified the predictors of volume reduction rate (VRR) of RFA versus MWA, and compared the efficacy between the two treatments. Consecutive benign nodules ≥ 80% solid, treated with a single session of RFA or MWA in a tertiary endocrine surgery center, with at least 12-month follow-up, were included. Propensity score matching (PSM) for baseline characteristics was performed to compare RFA vs MWA. The primary outcome was 12-month VRR. From 2021 to 2023, 208 nodules were analyzed (RFA: 142, MWA: 66). Maximum nodule diameter and initial nodule volume correlated with 12-month VRR (p < 0.001, correlation coefficient -0.360 and -0.322, respectively) of RFA but not MWA. PSM analysis for age, sex and maximum nodule diameter; or age, sex and initial nodule volume showed comparable overall 12-month VRR between RFA and MWA. In subgroup analysis, MWA achieved greater 3-month and 12-month (78.0% ± 15.5 vs 67.3% ± 17.6, p = 0.028) VRR for nodules with a maximum diameter ≥ 3.5 cm; and greater 6-month VRR for nodules with volume ≥ 20 mL (71.4% ± 16.7 vs 57.2% ± 16.1, p = 0.030). No significant complications occurred in either ablation modality. Larger nodule diameter and volume negatively correlated with the treatment efficacy of single-session RFA, but not MWA. Single-session MWA achieved greater VRR for nodules with maximum diameter ≥ 3.5 cm, or volume ≥ 20 mL. The results of this study prompt confirmation by future randomized controlled trials with stratification by nodule volume. Question The comparative efficacy of single-session radiofrequency ablation (RFA) versus microwave ablation (MWA) for benign solid thyroid nodules remains unclear and so are factors affecting treatment efficacy. Findings Larger nodule diameter and volume negatively correlated with efficacy of RFA. For smaller nodules, RFA and MWA were comparable. MWA may have better efficacy for larger nodules. Clinical relevance For smaller nodules (max diameter < 3.5 cm or volume < 20 mL), RFA and MWA were equally effective and safe. For larger nodules (max diameter ≥ 3.5 cm or volume ≥ 20 mL), MWA may be more efficacious. Verification with prospective trials that account for baseline nodule volumes is needed.

Thermal Ablation for T1N0M0 Papillary Thyroid Carcinoma: A Long-term Multicenter Comparative Study with Subgroup Analysis.

Background: In response to evidence of overdiagnosis and overtreatment of papillary thyroid carcinoma (PTC), the 2009 and 2015 American Thyroid Association (ATA) adult guidelines recommended less extensive surgery (lobectomy vs. total thyroidectomy) and more restricted use of postsurgical radioactive iodine (RAI) in management of PTC at low risk of recurrence. In 2015, active surveillance was suggested as a viable option for some <1-cm PTCs, or microcarcinomas. The 2015 ATA pediatric guidelines similarly shifted toward more restricted use of RAI for low-risk PTCs. The impact of these recommendations on low-risk adult and pediatric PTC management remains unclear, particularly after 2015. Methods: Using data from 18 Surveillance, Epidemiology, and End Results (SEER) U.S. registries (2000-2018), we described time trends in reported first-course treatment (total thyroidectomy alone, total thyroidectomy+RAI, lobectomy, no surgery, and other/unknown) for 105,483 patients diagnosed with first primary localized PTC (without nodal/distant metastases), overall and by demographic and tumor characteristics. Results: The declining use of RAI represented the most pronounced change in management of PTCs <4 cm (44-18% during the period 2006-2018), including microcarcinomas (26-6% during the period 2007-2018). In parallel, an increasing proportion of PTCs were managed with total thyroidectomy alone (35-54% during the period 2000-2018), while more subtle changes were observed for lobectomy (declining from 23% to 17% during the period 2000-2006, stabilizing, and then rising from 17% to 24% during the period 2015-2018). Use of nonsurgical management did not meaningfully change over time, impacting <1% of microcarcinomas annually during the period 2000-2018. Similar treatment trends were observed by sex, age, race/ethnicity, metropolitan vs. nonmetropolitan residence, and insurance status. For pediatric patients (<20 years), use of RAI peaked in 2009 (59%), then decreased markedly to 11% (2018), while use of total thyroidectomy alone and, to a lesser extent, lobectomy increased. No changing treatment trends were observed for ≥4-cm PTCs. Conclusions: The declining use of RAI in management of low-risk adult and pediatric PTC is consistent with changing recommendations from the ATA practice guidelines. Post-2015 trends in use of lobectomy and nonsurgical management of low-risk PTCs, particularly microcarcinomas, were more subtle than expected; however, these trends may change as evidence regarding their safety continues to emerge.

To assess the efficacy and safety of thermal ablation (TA) in managing follicular thyroid neoplasms (FN). This multicenter retrospective study involved participants diagnosed with FN across nine hospitals, undergoing microwave ablation or radiofrequency ablation from January 2014 to January 2024. Primary outcomes assessed were technical success and disease progression, with secondary outcomes including tumor size and volume changes, complete tumor disappearance, complications, and side effects. Subgroup analyses aimed to identify factors influencing tumor progression and complete disappearance. The study enrolled 375 patients (mean age: 43.2 years ± 14.9 [standard deviation]; 298 women) with 482 FNs, tracked over an average of 23.6 months, achieving a 100% technical success rate. Disease progression was observed in 4.8% (18/375) of patients, with a local recurrence rate of 3.7% (14/375) and new neoplasm occurrence of 1.1% (4/375). Multifocal neoplasms emerged as an independent risk factor for disease progression (hazard ratio [HR], 3.48; 95% CI, 1.16-10.45; P = 0.026). Tumor volume significantly reduced (P < 0.001), particularly within 1-3 months post-ablation, with complete tumor disappearance observed in 10.4% (39/375) of cases, more likely in tumors smaller than 2 cm (HR, 0.11; 95% CI, 0.06-0.23; P < 0.001). Complications occurred in 2.9% of patients, with major events in 2.1% and minor in 0.8%. TA is a safe and efficacious method for treating FN, showing low rates of disease progression and complications. Optimal outcomes may be achieved in patients with unifocal FN and neoplasms under 2 cm.

Background Current guidelines recommend radiofrequency ablation (RFA) as the first-line treatment for benign thyroid nodules. Purpose To compare the efficacy and safety of microwave ablation (MWA) and RFA for the treatment of predominantly solid benign thyroid nodules. Materials and Methods This prospective, randomized, open-label, multicenter study was conducted from August 2019 to February 2023. Participants with nonfunctioning, predominantly solid benign thyroid nodules from five institutions were randomly assigned with a 1:1 ratio to receive MWA or RFA treatment. Participants were followed up for at least 2 years. Primary outcomes were 6-month and 2-year volume reduction rate (VRR) of nodules after ablation. Secondary outcomes included VRR change over time, complications, and technique efficacy (defined as volumetric reduction ≥ 50% of the initial nodule volume). Continuous variables and categorical variables were compared using the t test and the χ2 test or Fisher exact test, respectively. Results This study included 76 participants in the MWA group (mean age, 46 years ± 12 [SD]; 58 female participants) and 76 in the RFA group (mean age, 50 years ± 13; 56 female participants). MWA was noninferior to RFA in terms of 6-month (mean difference, -5.6%; P = .01) and 2-year (-2.4%; P < .001) VRR after ablation. Comparing MWA and RFA, no evidence of a difference was observed for VRR change over time (mean difference from mixed-effects analysis, 6.9% [95% CI: -0.5, 13.9]; P = .73) or technique efficacy (91% vs 86%; P = .40). The most common major complication was voice change, which occurred in 6.6% of participants in the MWA group and 1.3% of participants in the RFA group (P = .21). Conclusion MWA and RFA showed comparable efficacy for treating participants with predominantly solid benign thyroid nodules. However, a larger sample size is needed to demonstrate that safety is comparable between the procedures. ClinicalTrials.gov Identifier: NCT04046354 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by McGahan in this issue.

To compare the clinical outcomes between radiofrequency ablation (RFA) and microwave ablation (MWA) for the treatment of T1N0M0 papillary thyroid carcinoma (PTC) in a large cohort. This retrospective study included 1111 patients with solitary T1N0M0 PTC treated with RFA (n = 894) or MWA (n = 215) by experienced physicians. A propensity score matching was used to compare disease progression, including lymph node metastases (LNM), recurrent tumors and persistent tumors, recurrence-free survival (RFS), volume reduction ratio (VRR), and complications between the RFA and MWA groups. The subgroup outcomes of T1a and T1b tumors treated with RFA and MWA were also compared. During a mean follow-up period of 41.7 ± 12.6 months, the overall incidence rates of disease progression, LNM, recurrent tumors, and persistent tumors were 2.1%, 0.7%, 1.2%, and 0.2%, respectively. Eight patients (0.7%) experienced transient voice change and recovered within 3 months. After 1:1 matching, there were no significant differences in disease progression (3.3% vs. 3.7%, p = 0.793), LNM (1.4% vs. 1.9%, p = 1.000), recurrent tumor (1.4% vs. 1.9%, p = 1.000), persistent tumors (0.5% vs. 0%, p = 0.317), RFS rates (96.7% vs. 96.3%, p = 0.821), VRR (99.3 ± 3.0% vs. 98.3 ± 8.5%, p = 0.865), tumor disappearance rate (87.9% vs. 81.4%, p = 0.061) and complications (1.4% vs. 1.9%, p = 1.000) between the RFA and MWA groups. For T1a and T1b tumors, clinical outcomes were comparable between RFA and MWA. RFA and MWA did not show significant differences in clinical outcomes for T1N0M0 PTC. The choice between RFA and MWA could depend on physician expertise and resources of local center resources. A qualified and experienced physician with extensive knowledge of the modalities is recommended when thermal ablation is performed. Question With radiofrequency ablation (RFA) and microwave ablation (MWA) used worldwide for T1N0M0 papillary thyroid carcinoma (PTC), is one of them superior to the others? Findings There were no significant differences in disease progression, recurrence-free survival, volume reduction ratio, tumor disappearance, or complications between techniques for solitary T1N0M0 papillary thyroid carcinoma. Clinical relevance The choice between RFA and MWA could depend on physician expertise and resources of the local center resources. A qualified and experienced physician with extensive knowledge of the modalities is recommended when thermal ablation is performed.