The impact of fine-needle aspiration biopsy on surgery for single thyroid nodules.

Biopsy by fine-needle aspiration has emerged as the most effective single technique for the investigation of single thyroid nodules. A comparison was made of patients who underwent surgery for single nodules in 1979 (before the introduction of fine-needle aspiration biopsy to this Department) and in 1984, after this technique had become fully established. Biopsy by fine-needle aspiration proved to be reliable in the selection of patients for surgery. The incidence of malignancy in each category was: malignant, 83%; atypical, 26%; inadequate, 7%; and benign, none. This contrasted with nuclear scanning and ultrasound techniques that were in use over that period, where the malignancy rate of nodules that showed no uptake of radioisotope was 11% and that of an ultrasound scan that demonstrated a "solid" or "cystic/solid" was 16%. Similarly, nodules that showed an uptake of radioisotope or an ultrasound scan that demonstrated a "cystic" image did not exclude malignancy reliably. As a result of fine-needle aspiration biopsy, there was a 60% reduction in the number of thyroidectomies for single nodules during its use with a higher yield, but no change in the absolute number, of patients with malignancy of the thyroid gland.