Diagnosis and management of thyroid carcinoma: a focus on serum thyroglobulin

Thyroid cancer is poised to become one of the most common cancer diagnoses in living cancer patients. Thyroglobulin (Tg) is thyroid but not tumor specific. Serum Tg levels less or equal to 0.1 ng/ml in patients without Tg autoantibodies (TgAbs) indicate cure following total thyroid ablation when measured on thyroxine with assays of functional sensitivity less or equal to 0.1 ng/ml. Less-sensitive assays might require stimulated Tg measurements. Tg measurement in biopsy-needle washes is becoming important as an adjunct to cytology in lymph node biopsies. The major limitations of Tg are false low interferences by TgAbs and a lack of established reference ranges for cured patients with thyroid remnants. Clinical acumen and neck ultrasound remain the best tools in TgAb-positive patients. For the increasing number of patients presenting with small indolent cancers who might receive less than total thyroid thyroidectomy, possibly without radioactive iodine remnant ablation, Tg reference ranges must be established for remnants, and tumor-specific markers need to be identified.