Dr. Daniels expresses concern about the cost of thyroid nodule evaluation when fine-needle aspiration biopsy is the first test. He advocates thyroid scan as an initial procedure and believes that when a thyroid scan is not used as an initial test, patients with hot nodules may be misleadingly subjected to thyroid surgery.

Van Herle and colleagues [1] reviewed the cost-effectiveness of the evaluation of a thyroid nodule and carefully outlined the sequence of test procedures that is most cost-effective when applied to patients with solitary or dominant thyroid nodules. Both fine-needle aspiration biopsy followed by a scan and a scan followed by fine-needle aspiration biopsy were highly sensitive (93%) as well as highly specific (91%). However, the strategy using fine-needle aspiration biopsy as the first diagnostic test had the lowest cost and was the most cost-effective. The strategy that used a scan first and then fine-needle aspiration biopsy was the most expensive and least cost-effective [1]. In this analysis, the cost of surgery was excluded and analysis was restricted to the cost of diagnostic tests. Our own experience supports these data.

Fewer than 5% of nodules appear hot on thyroid scanning; fewer than 5% of these hot nodules are suspicious according to results of fine-needle aspiration biopsy [2]. This would mean that, in fact, a small fraction of patients with hot nodules may have unnecessary thyroidectomy. Most of this small group of patients will have a benign cytologic diagnosis and should be monitored.

We continue to use fine-needle aspiration biopsy as the initial diagnostic test, reserving radionuclide scanning for situations in which cytology is nondiagnostic. We consider our approach reasonable and cost-effective.