title: Comparison of calcium and pentagastrin tests for the diagnosis and follow-up of medullary thyroid cancer.
abstract: BACKGROUND
  The evaluation of basal calcitonin (bCT) and stimulated calcitonin (sCT) can be used for the diagnosis and follow-up of medullary thyroid cancer (MTC).
  
  
  OBJECTIVE
  The aim of this study was to evaluate the reliability of high-calcium (Ca) test and to identify gender-specific thresholds for MTC diagnosis.
  
  
  METHODS
  Patients with MTC in remission (n=24) or in persistence (n=18), RET gene mutations carriers (n=14), patients with nodular goiter (n=69), and healthy volunteers (n=16) were submitted to pentagastrin and Ca (25 mg/kg) tests.
  
  
  RESULTS
  In all groups, the levels of calcitonin (CT) stimulated by either pentagastrin or Ca were significantly correlated. The prevalence of both C-cell hyperplasia (CCH) and MTC in women and men paralleled the increasing basal and peak CT levels in a gender-specific manner. Receiver operating characteristic plot analyses showed that the best levels of bCT to separate normal and CCH cases from MTC patients were above 18.7 pg/ml in females and above 68 pg/ml in males. Furthermore, Ca sCT above 184 pg/ml in females and above 1620 pg/ml in males had the highest accuracy to distinguish normal and CCH cases from patients with MTC. At the C-cell immunohistochemical examination, Ca sCT below 50 pg/ml corresponded to a mean number of 30 cells per 10 fields, whereas higher sCT associated with a mean number of 400 cells per 10 fields, often displaying a diffuse and nodular distribution pattern.
  
  
  CONCLUSIONS
  High-dose Ca test is a potent and well-tolerated procedure that can be applied worldwide at a low cost. Reference ranges for Ca sCT levels in different groups of patients and CT thresholds to diagnose CCH/MTC have been identified.
authors.affiliation: Department of Medical Sciences, University of Milan, Milan, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Colombo
authors.forename: Uberta
authors.initials: U
authors.lastname: Verga
authors.forename: Caterina
authors.initials: C
authors.lastname: Mian
authors.forename: Stefano
authors.initials: S
authors.lastname: Ferrero
authors.forename: Michela
authors.initials: M
authors.lastname: Perrino
authors.forename: Leonardo
authors.initials: L
authors.lastname: Vicentini
authors.forename: Davide
authors.initials: D
authors.lastname: Dazzi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Opocher
authors.forename: Maria Rosa
authors.initials: MR
authors.lastname: Pelizzo
authors.forename: Paolo
authors.initials: P
authors.lastname: Beck-Peccoz
authors.forename: Laura
authors.initials: L
authors.lastname: Fugazzola
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002116:Calcitonin / Q000097:blood*; D002118:Calcium; D018276:Carcinoma, Medullary / Q000097:blood / Q000175:diagnosis* / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010418:Pentagastrin; D015203:Reproducibility of Results; D013964:Thyroid Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000235:genetics; D016606:Thyroid Nodule / Q000097:blood / Q000175:diagnosis / Q000235:genetics
chemical_list: D002116:Calcitonin; D010418:Pentagastrin; D002118:Calcium