Endocrine Abstracts

Objectives: Assess the efficacy and safety of ultrasound-guided percutaneous ethanol injection (PEI) for treating benign cystic or predominantly cystic-thyroid nodules (TN).

Methods: Retrospective analysis of all euthyroid patients treated with PEI for purely (>90% of cystic component) or predominantly cystic (50%-90% of cystic component) TN between January 2018 to February 2023. Efficacy was defined as 50% or greater reduction in pretreatment volume with no recurrence. Safety was considered as no or mild PEI-related complications. Patients with incomplete data were excluded.

Results: In this analysis, 55 patients were included, of whom 39 were female (70.9%) and the median age was 55 (±16) years. The most common complaint was a cosmetic issue in 33 patients (58.2%), and 9 patients (16.4%) were symptomatic (4 with dysphagia, 1 with dysphonia, and 3 with neck pressure). PEI was used in 34 (61.8%) patients with predominantly cystic nodules. The median largest diameter of the nodules was 39.0 (P25-75: 34-46) mm, and the median initial volume was 14.7 (P25-75: 8.6-24.5) mL. During PEI sessions, the median amount of fluid drained was 8.0 (P25-P75: 4-13) ml, and the median amount of ethanol instilled was 3.0 (P25-P75: 1.3-5.0) mL. Overall, reductions of TN volume >50% were achieved in 46 (83.6%) of the nodules with a median follow-up of 30.8 (13-43) months. This was achieved in a median time of 8 (1-27) weeks after the 1st PEI. Around 56.4% (31) of the nodules were successful after just one session. No statistical differences were found in the success of PEI and the type of nodule. All symptomatic patients went into remission. However, 4 (7.3%) of the nodules with initial success did end up recurring after 99 [55-153] weeks on median. One of these patients underwent surgery due to the nodule becoming almost completely solid with over 30mm in size, and histopathology revealed a benign diagnosis. Adverse reactions (AE) were reported in 8 (14.5%) patients and were mostly mild. Six patients complained of mild reactions: 5 experienced a burning sensation during PEI, and 1 developed a local hematoma. Two patients developed more serious AEs: dysphonia (which improved after speech therapy) and Horner syndrome.

Conclusion: In our experience, PEI is an effective and generally safe procedure. The technique leads to significant reductions in nodule volume, with lasting effects. Additionally, all symptomatic patients experienced improvement. Further investigation in larger studies is warranted, given the limitations of our single-center, small sample size study.