Background and purpose: Percutaneous ethanol injection (PEI) has been established as an effective and safe treatment for thyroid cystic nodules (TCN). Certain tetracyclines have also been used successfully as sclerosing agents, and it has been proposed that a low pH might account for their efficacy in this indication. This study compared the effectiveness of ethanol and dilute hydrochloric acid (pH 1.0) in the sclerotherapy of TCN.
Methods: A total of 27 patients with TCN with a mean cystic volume of 16.6 mL (5-45 mL) were randomly assigned to receive 1 of the following 3 treatments: 1) needle aspiration only, 9 patients; 2) PEI, 10 patients; or 3) percutaneous hydrochloric acid injection (PHI), 8 patients. The procedures were performed weekly until cure was evident. Resolution was defined as the disappearance of cyst or reduction of cystic volume to below 0.5 mL. Treatment was considered a failure if the condition did not resolve after 5 sessions of intervention. The 10 original patients treated by PEI and 14 additional patients subsequently enrolled and treated by PEI were followed for 24 months in order to evaluate the long-term effects of PEI treatment. Follow-up physical examination and ultrasound scan was performed every 3 months during the first year and every 6 months during the second year. A cystic volume of greater than 1 mL was regarded as a recurrence.
Results: PHI did not have a better cure rate than aspiration alone (37.5% vs 44.4%, p = 0.778). PEI had a significantly higher cure rate than PHI (90% vs 37.5%, p = 0.023) and aspiration alone (90% vs 44.4%, p = 0.038). No patient who received aspiration only complained of cervical pain. Four patients who received PEI and 3 patients who received PHI complained of self-limited cervical pain soon after sclerosant injection. Completed follow-up in the 24 patients ranged from 3 to 24 months (mean, 15.5 +/- 7.7 months), and only 3 patients (12.5%) were found to have recurrence within the first 9 months. The likelihood of recurrence was not correlated with pretreatment cystic volume.
Conclusions: Use of a low-pH sclerosant (PHI) was of no benefit. PEI provides a rapid, tolerable, and sustained effect and can be used as first-line treatment in patients with TCN.