Early postoperative stimulated serum thyroglobulin quantifies risk of recurrence in papillary thyroid cancer

Background: Postoperative follow-up of papillary thyroid cancer includes serial serum thyroglobulin levels. This study aimed to determine whether stimulated thyroglobulin levels measured in the early postoperative period can accurately quantify the risk of recurrence in papillary thyroid cancer. Methods: We undertook a cohort study of patients who underwent total thyroidectomy for papillary thyroid cancer ≥10 mm in the period 2000 to 2016 with complete biochemical data. All patients had a postoperative stimulated thyroglobulin measured within 3 months after total thyroidectomy. Structural recurrence was defined as disease detected on imaging and confirmed on histology. Biochemical disease was defined as patients with stimulated serum thyroglobulin ≥1 ng/mL with no evidence of structural disease. Results: This study included 502 patients with a mean age of 50 years and median tumor diameter of 20 mm. Median follow-up was 18 months. Stimulated postoperative thyroglobulin was measured before radioiodine-ablation and was categorized into 3 groups: (1) 219 (44%) patients had thyroglobulin <1 ng/mL; (2) 55 (11%) had 1ng/mL ≤ thyroglobulin <2 ng/mL; and (3) 228 (45%) had thyroglobulin ≥2 ng/mL. The structural recurrence rate for each group was 5%, 2%, and 30%, respectively (P < .0001). Conclusion: In patients undergoing total thyroidectomy for papillary thyroid cancer, early postoperative stimulated thyroglobulin accurately quantifies the risk of structural disease recurrence.