Detection of recurrent papillary thyroid carcinoma by thyroglobulin assessment in the needle washout after fine-needle aspiration of suspicious lymph nodes.

To evaluate an efficient method of surveillance of low-risk patients with thyroid cancer, ultrasound was performed on 74 postoperative patients being followed for stage I and II papillary carcinoma. All patients were clinically free of cancer 1-43 years after a total thyroidectomy, and were screened with ultrasound and thyroglobulin (Tg) measurement while taking thyroid hormone suppression. Ultrasound revealed findings suspicious of recurrent disease in the lymph nodes of the neck in 21 patients. An ultrasound-guided fine-needle aspiration (FNA) to obtain material for cytology and Tg analysis was done on these 21 patients, 7 of whom tested positive for Tg in their needle washout. Only 3 of the 7 had detectable Tg in their serum, and only 5 of the 7 had positive cytology. Ultrasound (with FNA-Tg analysis of needle washout of suspicious lymph nodes) is proposed as an effective and efficient method of surveillance in these low-risk patients. Presence of Tg in the needle washout proved to be more sensitive than cytology in diagnosing cancer in the lymph nodes and was not affected by positive anti-Tg antibodies in the serum.