Mild Persistent Hypercalcitoninemia after Total Thyroidectomy in Patients with Papillary Thyroid Carcinoma

Abstract

Abstract. Total thyroidectomy was performed in 455 patients with differentiated thyroid carcinoma between 1978 and 1999. Serum calcitonin (CT) was determined preoperatively in all patients using polyclonal antibodies. Among the subjects, 25 patients showed elevated serum calcitonin levels preoperatively. Pathological diagnoses of 18 patients were confirmed as medullary thyroid carcinoma (MTC) postoperatively. Eight patients were diagnosed as papillary thyroid carcinoma (PTC) in the final pathological diagnosis without evidence of minimal foci of MTC or C cell hyperplasia, and they showed elevated CT levels preoperatively. Hypercalcitoninemia in 8 patients with PTC continued through out the 24 follow-up months with normal CEA levels. Extrathyroidal CT-producing diseases were all neglected, and precise pathological examination showed negative evidence of minute MTC or C cell hyperplasia in these 8 patients. Serum CT levels were simultaneously determined by a different CT assay kit using the same blood samples in 7 of 8 patients. Serum CT levels were all within normal values in another CT kit applying a different polyclonal antibody, although elevated CT values continued in the routine CT kit. The recognition of polymeric or fragmented CT by polyclonal antibody was thought to be the causative factor for the hypercalcitoninemia after total thyroidectomy in the patients with PTC. Knowledge of the false positive CT determination makes it important to employ different CT assay kits, especially the new generation of two-site immunoassays using two monoclonal antibodies against distinct epitopes of human CT, although the new generation kits are not clinically available in Japan.

Measurement of Calcitonin and Calcitonin Gene–Related Peptide mRNA Refines the Management of Patients with Medullary Thyroid Cancer and May Replace Calcitonin-Stimulation Tests

“…By contrast, the various sCT assays may have important intra-assay or interassay variation and may yield different and sometimes conflicting results (13,14). Beyond these caveats related to the assay reproducibility, a hook effect in samples with high levels of sCT and a cross-reaction with procalcitonin may happen, although these phenomena are uncommon with two-site monoclonal antibody assays (15)(16)(17)(18)(19). On the other hand, heterophilic antibodies (with a prevalence of 1.3% to 3.7%) or anti-calcitonin interference may occur and can sometimes be misleading (20)(21)(22)(23).…”

False positive results using calcitonin as a screening method for medullary thyroid carcinoma

“…[14] In these situations, basal calcitonin may be high, but rates after stimulation are usually lower than the ones observed in cases of MTC. [1420]…”

“…Differentiated thyroid tumors may cause increase in serum calcitonin, similar to the one observed in nonneoplastic diseases therefore much lower than that evidenced in MTC cases. [20] The main concern here is the rate of increase in calcitonin after the stimulation test. There is no established rate that can biochemically differentiate C cells hyperplasia from MTC.…”

Η Επιβίωση, Η Ποιότητα Ζωής, Η Συχνότητα Υποτροπής Και Ο Ρόλος Της Θυρεοσφαιρίνης, Μετά Ολική Θυρεοειδεκτομή, Σε Ασθενείς Με Καλώς Διαφοροποιημένα Καρκινώματα Του Θυρεοειδούς Αδένα

“…Σε αυτές τις περιπτώσεις ο ασθενής χρήζει δυναμικής δοκιμασίας με διέγερση των κυττάρων C με τη χορήγηση πενταγαστρίνης [51,150]. Προσοχή χρήζει το γεγονός ότι μετρίως αυξημένα επίπεδα καλσιτονίνης στο αίμα μπορούν να ανευρεθούν και σε περιπτώσεις παραγωγής της ορμόνης από άλλα κύτταρα, όπως αποδεικνύεται από τη μέτρηση των επιπέδων καλσιτονίνης σε ασθενείς που υποβλήθησαν σε ολική θυρεοειδεκτομή για άλλο λόγο [212]. Τα τελευταία χρόνια, η ανάπτυξη των τεχνικών της μοριακής βιολογίας και γενετικής, ανοίγει νέες οδούς διάγνωσης με τη μελέτη του γονιδιώματος και την ανεύρεση συγκεκριμένων μεταλλάξεων.…”