Long-term follow-up of cystic thyroid nodules treated with percutaneous ethanol injection (PEI) using two different...

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.

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.

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).

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.