PERCUTANEOUS ETHANOL INJECTION THERAPY IN THE TREATMENT OF THYROID AND PARATHYROID DISEASES

Relevant English language articles published from 1966 to 1995 regardi ng ethanol therapy in the treatment of thyroid and parathyroid disease s were identified through a MEDLINE search and manual searches of iden tified articles. The sclerosing properties of ethanol have been recogn ized for many years and have offered interventional possibilities in t he management of various benign as well as malignant lesions, The mech anism of action of ethanol appears to be related to a direct coagulati ve necrosis and local partial or complete small vessel thrombosis. Ult rasound-guided percutaneous ethanol injection therapy (PEIT) is rapid and performed on an out-patient basis and has now gained wide acceptan ce due to the accumulating evidence of the efficacy and safety of this therapeutic tool. Yet, there is a lack of prospective, randomized cli nical trials comparing PEIT with I-131 therapy or surgery with regard to its effects, especially long-term ones and it should therefore stil l be considered an experimental procedure. In benign endocrine disease s, PEIT has shown promising results in the treatment of autonomous thy roid nodules, benign solitary cold solid as well as cystic thyroid nod ules and parathyroid tumours. Its use in pretoxic and toxic thyroid no dules has been evaluated in several uncontrolled studies, all demonstr ating a high success rate in spite of the large number of treatments n eeded. So far efficacy and cost-effectiveness seem inferior to I-131 a nd surgery. Short-term results of PEIT in benign cystic thyroid nodule s are convincing with a high cure rate, but no controlled studies with long-term results are available. Preliminary results suggest that PEI T could become an alternative to surgical excision or levothyroxine th erapy in the symptomatic solid cold benign thyroid nodule. Ultrasound- guided PEIT of parathyroid tumours has proven to be a useful method in highly selected patients in whom surgery has been found non-attractiv e and medical treatment ineffective. However, no prospective randomize d trials have been published comparing the results of PEIT in parathyr oid tumours with conventional surgical and medical treatments. PEIT ha s never been tested against standard therapy, but seems inferior to I- 131 and surgery. Side-effects caused by ethanol injection are generall y few and transient and are related to the injection into solid nodule s rather than cysts. Ethanol injection into solid profund nodules may seriously jeopardize subsequent surgery because of perinodular fibrosi s. As an experimental procedure, not yet evaluated sufficiently, it sh ould be reserved for patients who cannot or will not undergo standard therapy. Caution in routine use is advisable.