Fine-needle aspiration of thyroid nodules in radiation-exposed patients

External radiation used to treat benign conditions in the head and neck are a results in an increased risk of thyroid cancer in exposed individuals. Fi ne-needle aspiration (FNA) biopsy is the standard procedure used to evaluat e suspicious thyroid nodules. Its accuracy has been extensively studied, bu t little is known about FNA in irradiated patients. We analyzed the FNA exp erience of 136 irradiated subjects. Fifty-two had surgery enabling a compar ison of the histologic diagnosis with the FNA results. In these 52 patients with a total of 53 FNAs, 20 were reported as benign, 14 as follicular neop lasms, 6 as papillary cancer, and 13 as inadequate samples. Seven malignant nodules were aspirated; 4 were reported as papillary cancer, 1 was reporte d as benign and 2 had inadequate specimens. An additional 11 patients had t hyroid cancer in foci that were not subjected to FNA, For the nodules that were aspirated, and considering an FNA report of follicular neoplasm as a f alse-positive when a follicular adenoma or a colloid nodule was found at su rgery, the calculated sensitivity was 80%, specificity 54%, positive predic tive value 20%, and negative predictive value 95%. Of the 14 follicular neo plasm FNA diagnoses, 10 were colloid nodules (71%), and 4 only were follicu lar adenomas. We conclude that the sensitivity of FNA in irradiated patient s is similar to what is reported for the general population. However, small er malignant nodules are common and are not diagnosed by the FNA. Also, the FNA diagnosis of follicular neoplasm is often inaccurate and inadequate as pirations are frequent in this patient group.