Utility of Early Postoperative Unstimulated Thyroglobulin in Influencing Decision Making in Patients with Papillary Thyroid Carcinoma

Background

Serum thyroglobulin is used to screen for disease persistence or recurrence of papillary thyroid carcinoma (PTC). We sought to assess the utility of early postoperative unstimulated thyroglobulin levels (uTg) as a decision-making tool to guide the use of radioactive iodine (RAI) in PTC patients.

Methods

We performed a retrospective analysis of a prospectively maintained database of patients surgically treated for PTC from 2015 to 2017. We analyzed uTg approximately 6 weeks postoperatively. Patients undergoing total thyroidectomy or completion thyroidectomy were included in the study, and patients were analyzed according to postoperative uTg and receipt of RAI.

Results

A total of 255 patients were analyzed, with 134 patients meeting the inclusion criteria. The median postoperative uTg was 0.3 ng/mL. Overall, 49.3% (66/134) of patients achieved the target uTg of ≤ 0.2 ng/mL at a mean time of 7.9 ± 0.3 weeks postoperatively; 60% (40/66) of patients who achieved uTg ≤ 0.2 ng/mL postoperatively did not receive RAI. A uTg ≤ 0.2 ng/mL was maintained at 6 months in 98.1% of patients, including 100% of patients who received RAI and 96.7% of patients who did not receive RAI (p = 0.8). Of those who did not receive RAI, none demonstrated structural disease recurrence on 6-month ultrasound. Patients with early postoperative uTg > 0.2–2.0 ng/mL showed benefit from RAI, while patients with uTg > 2.0 ng/mL did not achieve the targeted uTg level regardless of receipt of RAI.

Conclusions

Postoperative uTg may be used to guide the use of RAI. Achieving near-undetectable uTg within 6 weeks postoperatively could aid providers in assessing disease burden and minimize RAI use for patients with a low-risk of disease recurrence. Continued follow-up is necessary to accurately determine long-term outcomes.