Serum thyroglobulin testing after thyroid lobectomy in patients with 1-4 cm papillary thyroid carcinoma.

[BACKGROUND] The role of measuring serum thyroglobulin (Tg) levels in patients who have undergone lobectomy has not been proven. The goal of this research is to see if serum Tg levels can predict the recurrence of papillary thyroid carcinoma (PTC) after lobectomy.

[METHODS] The 463 patients with 1-4 cm PTC who underwent lobectomy between January 2005 and December 2012, were included in this retrospective cohort study. Postoperative serum Tg levels and neck ultrasound were evaluated every 6-12 months after lobectomy during a median 7.8-year follow-up period. The receiver operating characteristic (ROC) curve and its area under the ROC curve (AUC) was used to assess the diagnostic performance of serum Tg levels.

[RESULTS] During the follow-up, the structural recurrent disease was confirmed in 30 patients (6.5%). The serum Tg levels measured by initial Tg, maximal Tg, and last Tg did not differ statistically between the recurrence and non-recurrence groups. According to our findings, serial patterns of serum maximal Tg variations in 30 patients with recurrence showed no obvious trend and no rising trend toward recurrence before detecting recurrence. The AUC was 54.5% (IQR 43.1%-65.9%) in the ROC curve analysis, indicating that it was not significantly different from the random classifier.

[CONCLUSION] Serum Tg levels did not differ significantly between the recurrence and non-recurrence groups, and there was no tendency for the recurrence group to increase Tg levels. In patients with PTC who underwent lobectomy, monitoring Tg levels regularly provides little benefit in predicting recurrence.