Evaluation thyroglobulin level during suppressive therapy measured by ultrasensitive technique in the prediction of excellent response in patients with differentiated thyroid cancer

• Published in: Majallahī-i pizishk-i hastahī Īrān Vol. 30; no. 2; p. 109
• Main Authors: Javan, Farnaz Nesari, Ayati, Narjes, Sadri, Kayvan, Ramezanzadeh, Esmat, Farahmandfar, Fateme, Beheshti, Somayeh, Zakavi, Seyed Rasoul
• Format: Journal Article
• Language: English
• Published: Tehran Tehran University of Medical Sciences 01.01.2022
• Subjects: Cancer; Correlation coefficients; Evaluation; Therapy; Thyroid cancer; Thyroid gland
• ISSN: 1681-2824

Introduction: When ultrasensitive thyroglobulin (uTg) is measured serially in the first 12 months of treatment, it can probably predict recurrence of thyroid cancer without discontinuation of T4 or administration of rhTSH. Methods: Measurement of TSH, Tg, Anti-Tg Ab, and uTg was performed in all consecutive patients with low-intermediate risk DTC 2, 6, and 12 months after initial therapy. One year after surgery, response to therapy was evaluated. Tg and uTg levels in different time points and the trend of changes were used to predict response to therapy. Results: Overall, 37 patients with a mean age of 40.3 years were studied. The mean initial uTg was significantly lower than fTg (P=0.01). Overall, the correlation coefficient was 0.45 and increased to 0.71 in ftg<10 ng/ml (P=0.005). The majority of patients (91.9%) received a mean dose of 3.3± 2.2GBq of I-131. One year later, there was no significant difference in mean Tg and mean uTg between the two techniques (P=0.62). The mean offT4uTg is not significantly different between patients with incomplete response compared to other groups at the end of the follow-up (P=0.1). The slope of onT4uTg was 0.04±0.18 versus 0.24±0.82 in patients with and without incomplete response respectively (P=0.45). Using ROC analysis, onT4uTg slope of 0.0005 was the best cutoff to differentiate incomplete response from other responses, however, the sensitivity was only 54.5% and specificity was 75%. Conclusion: The trend of thyroglobulin level during suppressive therapy measured by the ultrasensitive technique cannot accurately predict excellent response in DTC patients.