Predictors of thyroglobulin  in the lymph nodes recurrence of papillary thyroid carcinoma undergoing total thyroidectomy

Abstract Background: To investigate the association between postoperative lymph nodes (LN) recurrence in papillary thyroid carcinoma (PTC) patients with different serum thyroglobulin (Tg) levels. Methods: This study included PTC patients who underwent total thyroidectomy (TT) with at least central neck dissection and then re-operated due to LNs recurrence between January 2013 and June 2018 These patients were divided by serum Tg levels. Results: Of all the 60 included patients, 49 underwent radioactive iodine (RAI) treatment. Maximum unstimulated Tg (uTg) ≥ 0.2 ng/mL were associated with larger diameter of recurrent LNs (P = 0.027), higher possibility of diameters of recurrent LNs ≥ 25mm (P = 0.023) and higher ratio of metastatic LNs (P < 0.001). Serum-stimulated Tg (off-Tg) ≥ 1ng/mL and unstimulated Tg detected at 1 week after RAI ablation (on-Tg) ≥ 0.2 ng/mL were associated with larger diameter of recurrent LNs and higher possibility of diameters of recurrent LNs ≥ 25mm. Number of metastatic LNs ≥ 8 was an independent predictor for maximum uTg ≥ 0.2 ng/mL (OR = 8.767; 95% CI =1.392-55.216; P = 0.021). Ratio of metastatic LNs ≥ 25% was an independent predictor for off-Tg ≥ 1 ng/mL (OR = 20.997; 95% CI =1.649-267.384; P = 0.019). Conclusion: Postoperative Tg-positive status was associated with larger size of recurrent LNs. Number of metastatic LNs ≥8 and ratio of metastatic LNs ≥ 25% was an independent predicator for uTg-positive and off-Tg-positive status, respectively.