Low correlation between serum thyroglobulin and 131I radioiodine whole body scintigraphy: implication for postoperative disease surveillance in differentiated thyroid cancer

Purpose: To evaluate postoperative serum thyroglobulin (Tg) as a reliable tumor marker in low-risk differentiated thyroid cancer (DTC). Methods: Two hundred and three patients met the selection criteria of >18 years old; who had undergone total or near total thyroidectomy; had a postoperative Tg, and had undergone 131I pre ablation whole body scan (PA-WBS). The primary endpoint was the correlation between Tg level and functional remnant thyroid tissues. Outcomes were categorized as concordant and discordant. Concordant results were positive Tg (>1 ng/ml) with positive PA-WBS or negative Tg (30 mU/l on thyroxine withdrawal protocol. Results: One hundred ten patients (54.1%) had discordant results (p 1 ng/ml, and 5 patients had negative PA-WBS and Tg 1 ng/ml and negative PA-WBS. There were 74 patients with high TSH (>30 mU/l) on abstention (thyroxine withdrawal protocol). Twenty-four (32.5%) had discordant results (p © 2022 Elsevier Inc.