Despite the generally well-reasoned article by Drs. Gharib and Goellner [1] on fine-needle aspiration thyroid biopsy, the management of thyroid nodules remains controversial. The cost of thyroid scans ($318 at the Mayo Clinic) has led many physicians to abandon the initial thyroid scan as an unnecessary expense. However, cost savings from the scan itself and the costs of subsequent scans required by using fine-needle aspiration biopsy first are ignored.

Can thyroid scans save patients from potentially avoidable thyroid surgery? The answer is uncertain but important. The estimated percentage of "hot" nodules with suspicious cytologic features ranges from 5% to 50%. If 25% of the hot nodules biopsied at the Mayo Clinic yield "suspicious" cytologic results, an additional 1.25% (one quarter of the 5% of hot nodules) will require surgery. Are there other situations in which a scan can prevent surgery? I am impressed with many patients in whom the firm lobe of Hashimoto thyroiditis (biopsies of which may yield suspicious cytologic findings) is misinterpreted as a nodule. When these patients are referred for thyroid scans, we can often prevent a biopsy by palpating the thyroid and informing the referring physician of the diagnosis; in some patients a thyroid scan showing that the entire lobe corresponds to the nodule suggests Hashimoto thyroiditis. Scans that show multiple nodules can help the clinician interpret a likely benign but technically insufficient fine-needle aspiration biopsy specimen. Repeated fine-needle aspiration biopsies or surgery may thus be prevented in some patients.

If a thyroid scan can prevent 2% of unnecessary operations, the monetary cost of the two approaches is equal. We cannot estimate the additional patient cost of a potentially avoidable operation.

Until a true prospective study of all patients with clinically detectable nodules is done, I see no compelling reason why thyroid scans should be considered an "additional" expense.