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Relationship between serum thyroglobulin and 18 FDG‐PET/CT in 131 I‐negative differentiated thyroid carcinomas
Author(s) -
Giovanella Luca,
Ceriani Luca,
De Palma Diego,
Suriano Sergio,
Castellani Massimo,
Verburg Frederik A.
Publication year - 2012
Publication title -
head and neck
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.012
H-Index - 127
eISSN - 1097-0347
pISSN - 1043-3074
DOI - 10.1002/hed.21791
Subject(s) - medicine , thyroid carcinoma , nuclear medicine , thyroglobulin , thyroid cancer , positron emission tomography , predictive value , thyroid
Abstract Background The purpose of this study was to assess the relationship between [ 18 F]‐fluorodeoxyglucose ( 18 FDG)‐positron emission tomography/CT ( 18 FDG‐PET/CT) and serum thyroglobulin (Tg) in patients with recurrent differentiated thyroid carcinoma (DTC). Methods Forty‐two patients with recurrent DTC and negative Tg antibodies were included in the study. All patients underwent 131 I therapy due to an increasing serum Tg with a corresponding negative 131 I posttreatment whole body scan. The 18 FDG‐PET/CT scans were then performed on all patients, serum Tg was measured concurrently, and respective results were compared. Results Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy of the 18 FDG‐PET/CT examination were 93%, 84%, 93%, 84%, and 90%, respectively. The sensitivity of 18 FDG‐PET/CT significantly increased in patients with serum Tg levels ≥4.6 ng/mL (96%) in comparison with patients having lower levels (25%; p < .001). Nonetheless, 3 of 27 patients (11%) with a true‐positive 18 FDG‐PET/CT still had a Tg <4.6 ng/mL. Conclusion Although 18 FDG‐PET/CT scans are more likely to be positive with pretest Tg levels ≥4.6 ng/mL, 11% of patients with DTC with a lower serum Tg level will still have a positive scan. Our findings are in contrast with the American Thyroid Association (ATA) guidelines, which only recommend to perform 18 FDG‐PET/CT in patients with Tg levels >10 ng/mL. © 2011 Wiley Periodicals, Inc. Head Neck, 2012