Thyroglobulin is a poor predictor of differentiated thyroid cancer in patients who undergo surgery for thyroid nodular diseases

Objectives Thyroglobulin, produced exclusively by thyroid follicular cells, serves as a specific tumor marker for the follow-up of differentiated thyroid cancer (DTC) patients after thyroidectomy. However, its role as a predictor of malignancy in patients with thyroid nodules is controversial. We assessed the potential role of preoperative serum thyroglobulin concentration to predict DTC in patients without a preoperative diagnosis of malignancy who underwent partial or total thyroidectomy. Methods This retrospective study included patients with a preoperative diagnosis of benign multinodular goiter (MNG) or a thyroid nodule with indeterminate cytology (INC) (Bethesda system categories III/IV) who underwent partial or total thyroidectomy between January 2014 and May 2019. We compared the patients’ demographic, clinical, imaging, and biochemical data according to their final diagnosis: DTC or benign thyroid nodular disease. Further statistical analysis included odds ratio calculation and receiver operating characteristic (ROC) curve analysis. Results Of 131 patients who met inclusion and exclusion criteria, the indication for surgery was benign MNG in 69 patients and a thyroid nodule with INC in 62 patients. A final diagnosis of DTC was reported in 18 of the 69 benign MNG patients (26%) and in 30 of the 62 thyroid nodule with INC patients (48%). The preoperative measurements of nodule diameter and serum thyroid-stimulating hormone and thyroglobulin concentrations did not significantly differ between patients with a final diagnosis of DTC and those with benign histology. Conclusions Preoperative serum thyroglobulin alone is insufficient to differentiate between malignant and benign thyroid nodular disease.