VASCULARITY-TARGETED PERCUTANEOUS ETHANOL INJECTION OF TOXIC THYROID ADENOMAS: OUTCOMES OF A FEASIBILITY STUDY PERFORMED IN THE USA.

Objective: The recommended treatment options for toxic adenoma (TA) in the USA are radioactive iodine ablation and surgical resection, with continued observation for pre-toxic adenoma (PTA). Percutaneous ethanol ablation (PEI) has proven efficacy in the treatment of TA and is widely available in Europe but not in the USA. Methods: Retrospective analysis was performed of all patients who underwent PEI for TA/PTA at the University of Utah, from January 2010 to 2018. Ultrasound-guided PEI, with injections targeting power Doppler-mapped blood vessels within the adenomas, was conducted. Functionality was confirmed using thyroid scintigraphy prior to PEI. Results: Eighteen adults (15 female) underwent PEI. Mean age was 41 ± 13.7 years. Baseline thyroid-stimulating hormone (TSH) was suppressed (0.06 ± 0.09 mU/L), with normal free thyroxine (FT4) 1.43 ± 0.39 ng/dL. Median nodule volume was 5.7 cm3 (interquartile range [IQR], 4.8 to 7.7 cm3 ). Seventy-eight percent (n = 14) underwent two or less PEI sessions. Median volume of ethanol used was 0.46 mL/mL nodule volume (IQR, 0.3 to 0.6 mL). There was a significant increase in TSH concentrations within the first 3 months after PEI (0.06 ± 0.09 mU/L vs. 1.22 ± 1.88 mU/L; P = .02), with a concomitant significant decrease in FT4 concentrations (1.43 ± 0.39 ng/day vs. 1.13 ± 0.25 ng/day; P <.01). Significant nodular volume reduction was observed following PEI (median 5.7 cm3 [IQR 4.8-7.7 cm3 ] vs. 2.5 cm3 [IQR 2.0-7.8 cm3 ]; P <.01). Conclusion: Vascularity-targeted PEI is safe and effective for treating PTA and TA. This unique approach required lower injected alcohol volume and fewer injections for therapeutic success. Abbreviations: ATA = American Thyroid Association; FT4 = free thyroxine; IQR = interquartile range; PD = power Doppler; PEI = percutaneous ethanol injection; PTA = pre-toxic adenoma; RAI = radioactive iodine ablation; RFA = radiofrequency ablation; TA = toxic adenoma; TT3 = total triiodothyronine; US = ultrasound.