Castro, M. Regina

Abstract Disclosure: S. Saad-Omer: None. M. Stan: None. M.R. Castro: None. J. Brito: None. J.E. Hallanger-Johnson: None. M.M. Ryder: None. Background: Thyroid fine needle aspiration (FNA) is a widely utilized diagnostic tool for evaluating thyroid nodules. The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) provides a standardized framework for classifying cytologic findings and guiding management. This study retrospectively reviews thyroid FNA cases at a large academic institution to analyze the distribution of Bethesda classifications.Methods: A retrospective review was conducted of all thyroid FNA cases done in the department of Endocrinology at a large academic institution performed from January 1st 2019 to October 3rd 2023. Thyroid FNA results were divided into categories according to the Bethesda classification system, such as benign, atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), follicular neoplasm (FN), suspicious for malignancy, malignancy and non-diagnostic. FNA results that were not able to be classified were labelled as other.Results: A total of 3,291 thyroid FNA cases were included in the analysis. The distribution of cases across the Bethesda categories revealed a significant proportion of benign findings, with 73.6% classified as benign. This was followed by 8.1% follicular neoplasm, 6.56% Papillary Thyroid Cancer, 6.62% Non-diagnostic, 2.4% Atypical, and 2.3% Suspicious. 0.5% of FNA results were classified as other.Conclusion: Overall our cohort was found to have similar findings in terms of benign and confirmed PTC nodules compared to recent literature; however, the rate of atypical and non-diagnostic nodules was found to be lower. Presentation: Monday, July 14, 2025

Abstract The use of radiofrequency ablation (RFA) of benign, symptomatic thyroid nodules is growing in clinical practice. Objective outcomes of symptom relief are needed to support the use of this treatment. Thus, a previously established thyroid nodule symptom scoring system was prospectively administered to patients prior to RFA of symptomatic thyroid nodules and then at 1, 3, 6, and 12 months following ablation. A total of 38 patients of mean age 57 years were treated with RFA between August 2022 and January 2024 and completed at least 1 follow-up survey. Five of these patients underwent simultaneous ablation of 2 thyroid nodules; the remainder had a single nodule treated. Mean modified symptom score prior to RFA was 3.5 (SD 1.6) with higher scores correlating with increasing baseline nodule volume (R = 0.46, P = 0.0038). Patient symptom scores decreased at the first 1-month survey (mean 1.2; SD 1.3) and 3-month survey (mean 0.9; SD 1.3) with durable response in those patients with more extended follow-up. In those patients with imaging follow-up, decreasing nodule size was shown to correlate with decreasing symptoms. The early results of this study show that RFA of benign, symptomatic thyroid nodules results in quantifiable symptom relief within 3 months of treatment. Such objective measures of symptom relief may be used to measure long-term durability of treatment.

Abstract Background Autonomously functioning thyroid nodules (AFTNs) constitute 5% to 7% of thyroid nodules and represent the second most common cause of hyperthyroidism following Graves’ disease. Currently, radioactive iodine (RAI) and surgery are the standard treatment options, and both incur a risk of postprocedural hypothyroidism and other surgery and radiation-related complications. Methods This work aimed at assessing the efficacy of radiofrequency ablation (RFA) as an alternative treatment option for resolving hyperthyroidism and the nodule volume rate reduction (VRR) and its associated adverse events. Results A total of 22 patients underwent RFA for a solitary AFTN. Seventy-two percent (n = 16) had subclinical hyperthyroidism, 9% (n = 2) had overt hyperthyroidism, and 18% (n = 4) were biochemically euthyroid on antithyroid medication. Average pretreatment TSH was 0.41 mIU/L (SD = 0.98) and free T4 1.29 ng/dL (SD = 0.33). Following a single RFA session, hyperthyroidism resolved in 90.9% (n = 20) and average VRR (61.13%) was achieved within 3 to 6 months following the ablation. Except for 1 nodule, none of the nodules grew during the follow-up period (16.5 months). Two patients (9%) developed transient tachycardia requiring short-term beta-blocker therapy, and 2 developed mild hypothyroidism requiring levothyroxine therapy. Two patients developed recurrent hyperthyroidism and elected to undergo lobectomy and repeat RFA respectively. No serious adverse effects were noted in this cohort. Conclusion RAI and/or surgery represent the standard of care for toxic adenomas, but RFA shows excellent efficacy and safety profile. Therefore, at centers with RFA expertise, it should be considered an alternative treatment strategy, avoiding radiation and surgery-related complications.

Abstract Disclosure: M. Dhanasekaran: None. A.A. Rajwani: None. M.R. Castro: None. J.C. Morris: None. J. Schmitz: None. R.A. Lee: None. M. Callstrom: None. M. Stan: None. Context: Autonomously functioning thyroid nodules (AFTNs) constitutes 5% of thyroid nodules and is the second most common cause of hyperthyroidism following Graves’ Disease. Untreated hyperthyroidism is associated with adverse cardiovascular and skeletal complications. Currently, radioactive iodine (RAI) and surgery are the standard treatment options for AFTNs, and both incur a risk of post-procedural hypothyroidism. To overcome this and other surgery/radiation-related complications, radiofrequency ablation (RFA) has been utilized in multiple countries (for both toxic and non-toxic thyroid nodules). It has been shown to induce significant nodule volume reduction along with restoration of normal thyroid function in many AFTNs. Methods: We present a single-center experience using RFA as an alternative treatment modality for AFTNs. The study's primary aim was to assess the efficacy of RFA in normalizing thyroid hormone concentration and restoring the euthyroid state. In addition, we analyzed the efficacy of RFA in nodule volume rate reduction (VRR) and its associated adverse events. Results: A total of 22 consecutive patients (17 F and 5 M) underwent RFA for a solitary AFTN (hot nodule in thyroid uptake and scan) under variable degrees of general anesthesia. 72% (n=16) had subclinical hyperthyroidism, 9% (n=2) had overt hyperthyroidism, and 18% (n=4) were biochemically euthyroid on anti-thyroid drugs (ATD). The mean age at the time of ablation was 52.09 years (SD= 14.6), with a mean BMI of 27.36 kg/m2 (SD= 4.67). Average pre-treatment TSH was 0.41 mIU/L (SD= 0.980) and free T4 1.29 ng/dl (SD= 0.33). The thyroid function was assessed after a single RFA session. TSH normalized in all patients within 3-6 months following the ablation. All four patients on ATD pre-treatment discontinued therapy within three months following the procedure. The average VRR (62.54%) was achieved within 3-6 months following the RFA, and importantly, none of the nodules grew back during the follow-up period (up to 24 months). Two patients (9%) developed transient tachycardia requiring short-term beta-blocker therapy, and two (9%) developed mild hypothyroidism requiring levothyroxine therapy. One patient, euthyroid post RFA, developed recurrent hyperthyroidism 45 months later and elected to undergo lobectomy. No serious adverse effects were noted in this cohort. Conclusions - RAI and/or surgery represent the standard of care for toxic adenomas but RFA shows excellent efficacy along with an excellent safety profile. Therefore at centers with RFA expertise it should be considered an alternative treatment strategy, avoiding radiation and surgery-related complications. Presentation Date: Saturday, June 17, 2023

Abstract Context Thyroid nodule risk stratification allows clinicians to standardize the evaluation of thyroid cancer risk according to ultrasound features. Objective To evaluate interrater agreement among clinicians assessing thyroid nodules ultrasound features and thyroid cancer risk categories. Design, setting, and participants We surveyed Endocrine Society and Latin American Thyroid Society members to assess their interpretation of composition, echogenicity, shape, margins, and presence of echogenic foci of 10 thyroid nodule cases. The risk category for thyroid cancer was calculated following the American College of Radiology-Thyroid Imaging Reporting & Data System (ACR-TIRADS) framework from individual responses. Main Outcomes and Measures We used descriptive statistics and Gwet’s agreement coefficient (AC1) to assess the primary outcome of interrater agreement for ACR-TIRADS risk category. As secondary outcomes, the interrater agreement for individual features and a subgroup analysis of interrater agreement for the ACR-TIRADS category were performed (ultrasound reporting system, type of practice, and number of monthly appraisals). Results A total of 144 participants were included, mostly endocrinologists. There was moderate level of agreement for the absence of echogenic foci (AC1 0.53, 95% CI 0.24-0.81) and composition (AC1 0.54, 95% CI 0.36-0.71). The agreement for margins (AC1 0.24, 95% CI 0.15-0.33), echogenicity (AC1 0.34, 95% CI 0.22-0.46), and shape assessment (AC1 0.42, 95% CI 0.13-0.70) was lower. The overall agreement for ACR-TIRADS assessment was AC1 0.29, (95% CI 0.13-0.45). The AC1 of ACR-TIRADS among subgroups was similar. Conclusions This study found high variation of judgments about ACR-TIRADS risk category and individual features, which poses a potential challenge for the widescale implementation of thyroid nodule risk stratification.

Abstract Context After a thorough evaluation most thyroid nodules are deemed of no clinical consequence and can be observed. However, when they are compressive, toxic, or involved by papillary thyroid carcinoma surgery or radioactive iodine (RAI) (if toxic) are the treatments of choice. Both interventions can lead to hypothyroidism and other adverse outcomes (eg, scar, dysphonia, logistical limitation with RAI). Active surveillance might be used for papillary thyroid microcarcinoma (PTMC) initially, but anxiety leads many cases to surgery later. Several ablative therapies have thus evolved over the last few years aimed at treating these nodules while avoiding described risks. Cases We present 4 cases of thyroid lesions causing concern (compressive symptoms, thyrotoxicosis, anxiety with active surveillance of PTMC). The common denominator is patients’ attempt to preserve thyroid function, bringing into focus percutaneous ethanol injection (PEI) and thermal ablation techniques (radiofrequency ablation [RFA] being the most common). We discuss the evidence supporting these approaches and compare them with standard therapy, where evidence exists. We discuss additional considerations for the utilization of these therapies, their side-effects, and conclude with a simplified description of how these procedures are performed. Conclusion Thermal ablation, particularly RFA, is becoming an attractive option for managing a subgroup of solid thyroid nodules, while PEI has a role in managing thyroid cysts and a select group of PTMC. Their role in the algorithm of thyroid nodule management is still being refined and technical expertise will be essential to reproduce the reported results into everyday practice.

Background Until 2015, standard of care for low-risk papillary thyroid cancer (PTC) >1 cm was a total or near-total thyroidectomy. Despite changes in guidelines and surgical management of low-risk PTC since 2015, little data are available regarding the effect on the need for additional surgery or risk for development of lymph node metastases. Our aim was to determine outcomes in patients who underwent initial thyroid lobectomy for low-risk PTC at a high-volume tertiary care institution. Methods Retrospective review of patients ≥18 years old with biopsy proven low-risk PTC 1-4 cm who underwent partial thyroidectomy (eg, lobectomy/isthmusectomy) at Mayo Clinic, Rochester, MN, between March 2016 and June 30, 2019. Results From 1481 thyroidectomies performed during study period, 940 contained PTC on final pathology. Of these, 87 (of 123) patients who had an initial thyroid lobectomy met inclusion criteria. Five (6%) of these patients proceeded to completion thyroidectomy (CT), with 3 requiring CT and radioactive iodine in the first postoperative year and 2 undergoing only CT in the second postoperative year. No postoperative complications were reported. No patient in this cohort required additional surgery or treatment for newly discovered lymph node metastases during the follow-up period. 43 (of 72, 60%) patients not on thyroxine therapy preoperatively were started on thyroxine therapy postoperatively. Conclusions Early outcomes for those undergoing thyroid lobectomy for low-risk PTC at our institution have been favorable. These results support the 2015 American Thyroid Association guidelines to offer lobectomy for those with low-risk PTC 1-4 cm.