EFFECTIVENESS OF THE THYROID SCAN IN EVALUATION OF THE SOLITARY THYROID-NODULE

Solitary, palpable thyroid nodules are common, but only a small percen tage are malignant. It is important to evaluate these nodules in a cos t-efficient manner that avoids missing a cancer. Historically, radiois otope imaging has played a major role in the workup of thyroid nodules ; however, with the advent of fine needle aspiration biopsy (FNAB), th is role has become less clear. From 1974 to 1994, 770 patients with a solitary nodule underwent thyroidectomy. Preoperatively, 471 had thyro id scans, and 149 had FNAB. The incidence of carcinoma in nodules exci sed on the basis of thyroid scan was 23 per cent, whereas the incidenc e of carcinoma was 37 per cent when FNAB was used (P = 0.003). Fine ne edle aspiration was a significantly better predictor of malignancy tha n thyroid scan and resulted in a smaller proportion of excisions for b enign nodules. Thyroid scan provided little additional information in those patients who underwent FNAB. Because thyroid scans add little in determining which nodules require surgical excision, they should no l onger be a routine part of the evaluation of a solitary thyroid nodule .