Background and aim: Cystic thyroid nodules (CNs), although generally benign, can cause compressive or aesthetic problems. Percutaneous ethanol injection (PEI) can represent an alternative to surgery. The present retrospective study evaluates: (i) the long-term outcome of CNs after PEI; (ii) the differences between two different PEI protocols; (iii) the CNs response according to the liquid component.
Materials and methods: The study comprises 358 nodules post-PEI followed for at least 2 years. PEI was performed according to two different treatment protocols with a single (Foggia) or double (Turin) alcohol injection. CNs were divided according to their composition: cystic (CYS) >90%, mainly cystic (M-CYS) 75-90%, mixed (MIX) 50-75%, solid-mixed (S-MIX) 35-50%. The volume reduction rate (VRR) was defined as nodule volume (mL) after PEI/nodule volume (mL) before PEI x 100.
Results: The 1-year VRR was significantly higher than that at 6 months (89.5% vs 72.9%, P = 0.0005), no differences were observed after 1 year. A significant difference between Turin and Foggia was observed only in VRR at early visit (79% vs 86%, respectively, P = 0.002) and recurrence rate (14% vs 24%, respectively, P = 0.001). Minor side-effects were infrequent. In 192 nodules with a 10-year follow-up CYS showed higher VRR than MIX and S-MIX nodules (P < 0.001).
Conclusion: Our study reported that the long-term outcome of CNs treated with PEI is excellent regardless of the PEI technique utilized; the larger the cystic amount, the higher the VRR. Based on present results, PEI can be considered as the first-line choice for treating thyroid CNs.