Treatment of solitary, autonomously-functioning, non-toxic thyroid nodules with I131

Abstract

Fifteen euthyroid patients (14 women and 1man) with solitary autonomously functioning non-toxic thyroid nodules (AFTN) were treated with high doses of I¹³¹ (mean 19.2 mCi). Diagnosis was made by I¹³¹ thyroid scan and triiodothyronine suppression test. The size of the nodule was determined by thyroid ecography both before and after treatment. Evaluation of thyroid function was performed clinically and by T3 T4 and TSH determinations before therapy and during follow.up. AII patients had complete suppression of the surrounding thyroid parenchyma. Two cases of hypothyroidism were found in the first two years of follow-up. We have no explanation for this fact since extranodular thyroid tissue was suppressed and the patients were receiving oral triiodothyronine during radioidine treatment. The nodules decreasedin size In 9 of 13 patients followed (average decrease 45%) and disappeared in other 2. our findings suggest that solitary non-toxic AFTN should be treated with I¹³¹ particularly if complete suppression of the surrounding thyroid tissue is found. If complete disappearance of the nodule is considered desirable surgical removal must be performed.