Objective: To provide an overview of ultrasound (US)-guided percutaneous ethanol injection (PEI) therapy for thyroid cystic nodules and discuss the practical and technical details.
Methods: We present preliminary data of a controlled randomized study involving 281 patients (221 women and 60 men; 18 to 85 years old) with benign thyroid cystic nodules. Study inclusion criteria were local discomfort or cosmetic damage, cystic volume more than 2 mL, 50% or more fluid component, benignity as confirmed by cytologic specimen obtained by US-guided fine-needle aspiration biopsy (FNAB), and euthyroidism. Exclusion criteria were inadequate, suspicious, or positive FNAB cytology, high serum calcitonin, and contralateral laryngeal cord palsy. By random assignment, 138 patients underwent simple cyst evacuation, and 143 underwent cyst evacuation plus PEI by a skilled operator using a US-guided technique. The amount of ethanol injected was 50 to 70% of the cystic fluid extracted.
Results: Before treatment, the mean (+/-SD) nodule volume was 19.0 +/- 19.0 mL versus 20.0 +/- 13.4 mL in the PEI versus the simple evacuation group (no significant difference). After 1 year, volumes were 5.5 +/- 11.7 mL versus 16.4 +/- 13.7 mL (P<0.001), with a median 85.6% versus 7.3% reduction, respectively (P<0.001), of the initial volume. The median nodule volume reduction after PEI was 88.8% and 65.8% in empty body and mixed thyroid cysts, respectively. Compressive and cosmetic symptoms disappeared in 74.8% and 80.0% of patients treated with PEI versus 24.4% and 37.4% of patients treated with simple evacuation, respectively (P<0.001). Side effects were minor.
Conclusion: These data provide definitive evidence that PEI is a safe and effective treatment for thyroid cystic nodules. Unicameral thyroid cysts are the most suitable candidate nodules for PEI.