Efficacy and Safety of Single-Session Radiofrequency Ablation in Treating Benign Thyroid Nodules: A Short-Term Prospective Cohort Study

Radiofrequency ablation for thyroid nodules in Ecuador: a cross-sectional study

OBJECTIVES

To describe the demographic characteristics and clinical outcomes following the first cohort of patients with Bening Thyroid Nodule (BTN) and (Papillary Thyroid Microcarcinoma) (PTMC) treated with Radiofrequency Ablation (RFA)in Ecuador.

METHODS

Single-center, cross-sectional study. We included adults undergoing RFA for BTN and PTMC between July 2019 and May 2022. Descriptive statistics and the Wilcoxon signed-rank test were used to compare some pre- and post-intervention outcomes.

RESULTS

We included 44 patients with 36 BTNs and eight PTMCs. The median age was 45.80 years (IQR 16-79 years), and most patients had normal thyroid function (72.72%). The median follow-up time was 7.80 months (IQR1.0-34.0). Nodules were primarily solid (43.21%) or predominantly solid (56.81%). The pre-RFA median volume in the benign lesions group was 10.30 ml (IQR 1.86-18.97). After ablation, the 1-month, 3-month, 6-month, and 12-month median volumes were 6.90 (IQR 0.48-10.15; p < 0.01) mL, 5.72 (IQR 0.77-7.25; p = 0.045); 0.98 (IQR 0.25-3.64; p < 0.01), and 0.11 (IQR 0.07-11.26; p = 0.026), respectively. The volume rate reduction was 47.20%, 72.20%, 74.00%, and 96.20% at 1, 3, 6, and 12-month follow-ups, respectively. The pre-RFA median volume in the PTMC group was 0.25 ml (IQR 0.19-0.48). After ablation, the 1-month, 3-month, and 6-month mean volumes were 0.19 (range 0.12-0.31; p = 0.120) mL, 0.10 (IQR 0.05-0.15; p = 0.13), and 0.01 (IQR 0.005-0.04; p = 0.364), respectively.

CONCLUSIONS

In this first report from Ecuador, we found that RFA may be a feasible alternative for treating benign and malignant thyroid nodules in the short term. Long-term data are needed to evaluate oncologic outcomes in PTMC patients.

Model-Optimizing Radiofrequency Parameters of 3D Finite Element Analysis for Ablation of Benign Thyroid Nodules

Radiofrequency (RF) ablation represents an efficient strategy to reduce the volume of thyroid nodules. In this study, a finite element model was developed with the aim of optimizing RF parameters, e.g., input power and treatment duration, in order to achieve the target volume reduction rate (VRR) for a thyroid nodule. RF ablation is modelled as a coupled electro-thermal problem wherein the electric field is applied to induce tissue heating. The electric problem is solved with the Laplace equation, the temperature distribution is estimated with the Pennes bioheat equation, and the thermal damage is evaluated using the Arrhenius equation. The optimization model is applied to RF electrode with different active tip lengths in the interval from 5 mm to 40 mm at the 5 mm step. For each case, we also explored the influence of tumour blood perfusion rate on RF ablation outcomes. The model highlights that longer active tips are more efficient as they require lesser power and shorter treatment time to reach the target VRR. Moreover, this condition is characterized by a reduced transversal ablation zone. In addition, a higher blood perfusion increases the heat dispersion, requiring a different combination of RF power and time treatment to achieve the target VRR. The model may contribute to an improvement in patient-specific RF ablation treatment.

Effect of ultrasound parameters of benign thyroid nodules on radiofrequency ablation efficacy

BACKGROUND AND AIM

Ultrasound-guided radiofrequency ablation (RFA) is a minimally invasive therapy for thyroid nodules (TNs). Understanding the determinants of RFA efficacy can improve treatment and prognosis. This study aims to investigate the relationship between ultrasound parameters of benign TNs and the efficacy of RFA.

METHODS

A pretest-posttest interventional study was conducted in 2021 on 250 randomly sampled patients with benign TNs, receiving RFA. For this purpose, the volume reduction (VR) and the VR ratio (VRR) of the nodules were measured at the 1-, 3-, 6-, and 12-month follow-up periods after the RFA completion. The technical success rate (TSR) of this procedure was then categorized into four states, including low (VRR < 25%), moderate (VRR = 25-49%), high (VRR = 50-74%), and very high (VRR ≥ 75). Ordered logistic regression (OLR) was further utilized to investigate the effect of the ultrasound parameters of TNs on the TSR. The analyses were notably performed using Stata 14.2.

RESULTS

The VRR at the 1-, 3-, 6-, and 12-month follow-up periods were 38.7%, 53.6%, 59.3%, and 59.9%, respectively. The mean VR was also statistically significant at all follow-ups (p < 0.001). At the 1-, 3-, and 6-month follow-up periods, the VR of over 50% was observed in 28.2%, 52.1%, and 65.2% of the nodules, respectively. The odds ratios (ORs) of the RFA success were found to be 4.3 times higher for the nodules in the left lobe compared to the right lobe (OR: 4.31, p = 0.002), 6.3 times greater for isoechoic nodules compared to hyperechoic nodules (OR: 6.39, p < 0.001), 6.2 times higher for hyper-vascular nodules compared to hypo-vascular nodules (OR: 6.25, p = 0.005), and 2.3 times greater for mixed nodules compared to solid ones (OR: 2.37, p = 0.049).

CONCLUSION

The ultrasound parameters of TNs had a statistically significant effect on the efficacy of RFA. Small-sized, isoechoic, and hyper-vascular nodules, as well as those with mixed tissue, were observed to respond better to RFA, leading to a better prognosis in terms of VR after treatment.

Efficacy and Safety of Radiofrequency Ablation for the Treatment of Autonomously Functioning Thyroid Nodules: A Long-Term Prospective Study

Objective

This study aims to evaluate the efficacy and safety of RFA in the AFTN treatment after 2 years of follow-up and to find the factors related to treatment responses through TSH level and VRR.

Materials and Methods

This long-term prospective study was conducted from September 2017 to April 2021 on 17 AFTNs treated with RFA. Clinical evaluations, thyroid function tests, thyroid scintigraphy, and ultrasonography examinations were performed at 1 month, 3 months, 6 months, and 24 months after ablation. The primary endpoint was the success rate of RFA in restoring the euthyroidism stage after 24 months of follow-ups; secondary outcomes were VRR and improvements of US parameters, clinical examinations, and complications. The Spearman rank correlation test was used to determine related factors with treatment response variables.

Results

At the 24 months after the procedure, symptom score, cosmetic score, vascularity grade, and nodule volume significantly decreased. The VRR reduced approximately 42.77%, 63.13%, 78.3%, and 95.65% after 1 month, 3 months, 6 months, and 24 months follow-up. All 17 patients were restored euthyroid state without taking ATDs. No major complications were collected. The last TSH level was significantly correlated with the age of patients (Spearman rho = −0.637, p = 0.008). The VRR was significantly correlated with age of patients (Spearman rho = 0.566, p = 0.018) and initial TSH (Spearman rho = 0.485, p = 0.048).

Conclusion

RFA was demonstrated as a safe and effective option for AFTN treatment in long-term follow-up. It can be used as an alternative treatment with encouraging results.

Safety and efficacy of thermal ablation for cervical metastatic lymph nodes in papillary thyroid carcinoma: A systematic review and meta-analysis

BACKGROUND

To 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).

METHODS

The 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.

RESULTS

17 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).

CONCLUSION

All 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.

Long-term outcome of microwave ablation for benign thyroid nodules: Over 48-month follow-up study

OBJECTIVES

The short-term effects of microwave ablation (MWA) for the treatment of benign thyroid nodules (BTNs) were satisfactory in previous studies. However, as a slowly progressing disease, the long-term efficacy of MWA for BTNs at present is not clear. Our study aim was to assess the long-term results of MWA for BTNs after a 48-month follow-up.

METHODS

From June 2015 to September 2017, 148 patients had 148 BTNs. All patients were from the China-Japan Union Hospital of Jilin University. Careful ultrasound examinations were performed 1 day, 1 month, 3 months, 6 months, 12 months, and every 6 months after MWA. The volume, volume reduction rate (VRR), recurrence rate of the ablated area and thyroid function were recorded.

RESULTS

The mean volumes of the 148 nodules were 15.6 ± 9.4 cm³ (range: 1.3-48.9 cm³) and 0.6 ± 0.6 cm³ (range: 0-3.5 cm³) before and 48 months after MWA, respectively, with a nodule VRR of 96.9 ± 2.5% (range: 90.4-100%). Two patients (1.35%) had recurrence after MWA. Compared with thyroid function before MWA, no significant variation was observed after MWA. Five patients experienced complications (3.38%): two patients (1.35%) had bleeding, two patients (1.35%) had ear pain and toothache during MWA, and one patient (0.68%) had hoarseness after MWA. No cases of oesophageal injury, tracheal injury, infection, skin burns, etc., were reported during or after MWA.

CONCLUSIONS

Based on a long-term follow-up, MWA is an effective method for treating BTNs and is expected to be a potential first-line treatment.