Ultrasound-guided percutaneous ethanol injection in the treatment of autonomous thyroid nodules - a review

Percutaneous ethanol injection therapy (PEIT) in patients with autonomously functioning thyroid nodules (AFTN) has been evaluated with respect to indication for PEIT, treatment procedure, results of therapy and side effects of this treatment. As PEIT has not been tested against the standard procedure of radioiodine treatment and surgery up to now, PEIT should be an alternative treatment for selected patients who cannot or will not be treated by radioiodine therapy or surgery. The clinical data available demonstrate that better results are obtained in patients with euthyroid AFTN or AFTN with subclinical hyperthyroidism as compared to patients with AFTN and overt hyperthyroidism, particularly in small thyroid nodules (thyroid nodular volume less than 15 mi). After PEIT significant reduction of thyroid nodular volume can be achieved (reduction 21 to 88 %). Adverse events of PEIT are few and usually mild and with special respect to transient dysphonia, strongly correlated with the technical skills of the operator. Limitations of PEIT are mainly the need of repeat ethanol injections in order to achieve a complete cure of AFTN. In conclusion, a prospective controlled randomized clinical study has to be carried out in patients with AFTN in order to define the role of PEIT in comparison to the standard therapies (radioiodine treatment, surgery), in the treatment of patients with AFTN conclusively. Since more than 15 years the alternative therapy of ultrasound-guided percutaneous ethanol injection therapy (PEIT) has been used in individually selected cases in order to achieve therapeutic control of both malignant and non-malignant diseases (13, 15). Not only in endocrine glands but also in various other organs, soft tissues and bone numerous applications have been carried out and a beneficial effect of this treatment could be demonstrated in a remarkable percentage of patients. Although the currently available therapies for autonomously functioning thyroid nodules (AFTN) are either surgery or radioactive iodine, probably due to side-effects and high prevalence of hypothyroidism after surgery or radioiodine therapy, PEIT was first proposed by Livraghi et al (11) in 1990 as an alternative novel therapeutic tool in the treatment of AFTN. In the following years several, mainly Italian groups have carried out PEIT in patients with AFTN, presenting with overt (toxic adenoma), subclinical (pretoxic adenoma) hyperthyroidsm or euthyroidism (compensated adenoma) and reported their results. The following review summarizes all relevant articles published from 1990 to 1997 regarding PEIT in the treatment of AFTN. The aim of the review is to highlight the indication for PEIT in patients with AFTN, the characteristics of the treatment procedure, the results and side effects of PEIT concerning advantages and disadvantages of this method based on the data published.