Predictive Role of Serum Thyroglobulin after Surgery and before Radioactive Iodine Therapy in Patients with Thyroid Carcinoma

Alberto Signore; Chiara Lauri; Arianna Di Paolo; Valeria Stati; Giuliano Santolamazza; Gabriela Capriotti; Daniela Prosperi; Anna Tofani; Stefano Valabrega; Giuseppe Campagna

doi:10.3390/cancers15112976

Predictive Role of Serum Thyroglobulin after Surgery and before Radioactive Iodine Therapy in Patients with Thyroid Carcinoma

Cancers (Basel). 2023 May 30;15(11):2976. doi: 10.3390/cancers15112976.

Authors

Affiliations

¹ Nuclear Medicine Unit, Department of Medical-Surgical Sciences and of Translational Medicine, "Sapienza" University of Rome, 00185 Rome, Italy.
² Medical Oncology 2, IRCCS "Regina Elena" National Cancer Institute, 00144 Rome, Italy.
³ Surgical Unit, Department of Medical-Surgical Sciences and of Translational Medicine, "Sapienza" University of Rome, 00185 Rome, Italy.
⁴ Nuclear Medicine Unit, Sant'Andrea University Hospital, Via di Grottarossa 1035, 00189 Rome, Italy.

Abstract

Introduction: Thyroidectomy followed by radioactive iodine therapy (RAI) is the treatment of choice for differentiated thyroid carcinoma (DTC). Serum thyroglobulin (Tg) measurement has proved to be useful for predicting persistent and/or recurrent disease during follow-up of DTC patients. In our study, we evaluated the risk of disease recurrence in patients with papillary thyroid carcinoma (PTC), who were treated with thyroidectomy and RAI, by measuring serum Tg at different time-points: at least 40 days after surgery, in euthyroidism with TSH < 1.5 and usually 30 days before RAI (Tg_-30), on the day of RAI (Tg₀), and seven days after RAI (Tg₊₇).

Methods: One hundred and twenty-nine patients with PTC were enrolled in this retrospective study. All patients were treated with ¹³¹I for thyroid remnant ablation. Disease relapse (nodal disease or distant disease) during at least 36 months follow-up was evaluated by serum measurements of Tg, TSH, AbTg at different time points and by imaging techniques (neck ultrasonography, ¹³¹I-whole body scan (WBS) after Thyrogen^® stimulation). Typically, patients were assessed at 3, 6, 12, 18, 24, and 36 months after RAI. We classified patients in five groups: (i) those who developed nodal disease (ND), (ii) those who developed distant disease (DD), (iii) those with biochemical indeterminate response and minimal residual thyroid tissue (R), (iv) those with no evidence of structural or biochemical disease + intermediate ATA risk (NED-I), and (v) those with no evidence of structural or biochemical disease + low ATA risk (NED-L). ROC curves for Tg were generated to find potential discriminating cutoffs of Tg values in all patients' groups.

Results: A total of 15 out of 129 patients (11.63%) developed nodal disease and 5 (3.88%) distant metastases, during the follow-up. We found that Tg_-30 (with suppressed TSH) has the same sensitivity and specificity than Tg₀ (with stimulated TSH), and it is slightly better than Tg₊₇, which can be influenced by the size of the residual thyroid tissue.

Conclusion: Serum Tg_-30 value, measured in euthyroidism 30 days before RAI, is a reliable prognostic factor to predict future nodal or distant disease, thus allowing to plan the most appropriate therapy and follow-up.

Keywords: differentiated thyroid cancer; radioactive iodine; thyroglobulin.

Grants and funding

This research received no external funding.