Fine needle aspiration of thyroid nodules in a rural setting

The purpose of this study was to evaluate the applicability of fine needle aspiration biopsy (FNAB) of thyroid nodules in rural practices with smaller patient numbers, to assess the effect of these numbers on the results, and to establish the level of accuracy of the procedure in this setting.

We retrieved all thyroid FNAB reports identified as being performed by a single practitioner in a referral endocrine practice in Rapid City, South Dakota, between September 30, 1987, and September 30, 1991. Biopsy results are separated by year to establish correlations with the number of biopsies and outcomes. Follow-up pathology reports were obtained for all patients known to have undergone surgery.

A total of 189 FNABs in 165 patients were available for review from a 4-year period. The number of FNABs increased progressively from 28 per year to 65 per year during the 4-year course of the study. The incidence of inadequate specimens decreased inversely from 18% to 6% with the increase in the number of FNABs. The percentage of surgical interventions in which malignancy was found increased from 23% to 50% over the same period. Analysis of the results suggests that accuracy and specificity are comparable to results from larger centers.

FNAB of thyroid nodules can substantially reduce surgical intervention and increase the yield of malignancy without excessive loss of accuracy even in rural areas with small numbers of patients. Improved results as the number of biopsies increased to 50 or more per year suggest benefits from concentrating biopsies with as few operators as practical.