Radiofrequency ablation for benign thyroid nodules according to different ultrasound features: an Italian multicentre prospective study

Abstract

Background The purpose of this study was to confirm the generalisation of radiofrequency ablation (RFA) in the treatment of benign thyroid nodules (BTN) and to look for a correlation between final shrinkage and some ultrasound (US) findings in a large Italian population data set. Methods This prospective study included 337 patients with solid cold BTN from six Italian institutions. Nodule volume, US pattern, thyroid function, symptom/cosmetic scores and complications were evaluated before treatment and at 6 and 12 months. The primary outcome was to find a correlation between basal volume and US pattern of the nodules and final shrinkage. The secondary outcome was to confirm the efficacy and safety of RFA in a large data set. Results The median basal volume was 20.7 mL, and this significantly decreased after RFA at 6 months (7.3 mL (−63.5%), P < 0.001) and at 12 months (6 mL (−70%), P vs 6 months = 0.009). A significant correlation was found for US structure (a spongiform pattern showing a 76% reduction vs 67 and 66% of mix and solid patterns respectively, P < 0.01) as well as for vascularity (intense peripheral and intranodal patterns showing 71 vs 68 and 67% of weak peripheral and intranodal and peripheral patterns respectively, P < 0.03), but not for macrocalcifications. A slight inverse correlation was found between nodule basal volume and shrinkage (Spearman: −0.23). Mean symptoms/cosmetic scores were significantly reduced. No major complications were encountered. Conclusions This multicentre study validated the efficacy and safety of RFA for treating BTN and showed a clear correlation between final shrinkage and some common US findings.

Machine Learning Prediction of Radiofrequency Thermal Ablation Efficacy: A New Option to Optimize Thyroid Nodule Selection

“…Nodule volume exceeding 20-30 mL (> 3-4 cm of maximum diameter) and less delivered energy resulted in less efficacy. Literature data indicate that larger nodules receive proportionally less energy as compared to smaller nodules [16,27].…”

“…As RF is an operatordependent technique, another critical issue pertains to the skill of the operator [28]. At such, it is worth noting that in two studies using RF, the performance of different centers was not significantly different, indicating that the use of shared techniques results in similar VRRs [16,29]. As a matter of fact, if the performance among different centers was different, the machine learning model would not have been correctly trained and as a consequence, would not have displayed a valid response prediction.…”

“…In addition to quantitative measures such as nodule volume and delivered energy, structural features are also crucial. Both with RA and L, spongiform appearance of the nodule and intranodular vascularity are associated with a better response, probably because heat spreads more thoroughly than in compact nodules and periphery-only vascularized nodules [9,16,30].…”

“…The machine learning model was trained with a dataset consisting of 402 Italian patients with cytologically benign nodules subjected to RF at six Italian Institutions (benignity was confirmed by two repeated fine-needle aspirations, Class II of Bethesda reporting system). Data from 337 patients were obtained from a prospective study published by Deandrea et al [16], and additional data from 65 patients were obtained from the Division of Endocrinology at the Mauriziano Hospital (Turin), and recruited with the same modality. All Institutions shared the same training program, and at least 50 RF procedures had been performed using the same unified protocol and similar devices.…”

2020 European Thyroid Association Clinical Practice Guideline for the Use of Image-Guided Ablation in Benign Thyroid Nodules

“…As a general rule, the smaller the treated nodule the higher the volume reduction (78-82% in ≤10to 12-mL nodules vs. 62-65% in > 20-to 30-mL nodules) [56,57]. As tissue structure affects the alternating current flow, compact tissues are more resistant than soft tissues and, as for LTA, spongiform and mixed nodules respond better to RFA than solid lesions [58,59]. RFA treatment has been shown to ameliorate pressure as well as cosmetic symptom scores [58,60].…”