title: Predictive value of serum calcitonin levels for preoperative diagnosis of medullary thyroid carcinoma in a cohort of 5817 consecutive patients with thyroid nodules.
abstract: BACKGROUND
  Routine serum calcitonin (CT) measurement in patients with thyroid nodules for diagnosis of medullary thyroid carcinoma (MTC) is controversial.
  
  
  OBJECTIVE
  The objective of this study was to evaluate the diagnostic accuracy of systematic CT measurement in non-multiple endocrine neoplasia type 2 patients with nodular thyroid disease.
  
  
  METHODS
  This study was conducted at a national healthcare system hospital (outpatient and inpatient sectors).
  
  
  METHODS
  Consecutive patients with nodular thyroid disease (n = 5817) were studied.
  
  
  METHODS
  Serum CT levels were measured under basal conditions, and when basal values were more than or equal to 20 and less than 100 pg/ml, testing was repeated after pentagastrin stimulation. Basal or stimulated levels more than 100 pg/ml were indication for surgery.
  
  
  RESULTS
  Fifteen cases of MTC and seven of C cell hyperplasia (CCH) were identified. MTCs were diagnosed in all patients with basal CT more than 100 pg/ml. The four patients with basal CT more than or equal to 50 and less than 100 pg/ml included two diagnosed with MTC and two with CCH. In 10 patients with basal levels more than or equal to 20 and less than 50 pg/ml, histology confirmed the presence of MTC in four, four others had CCH, and the remaining two were negative for thyroid malignancy. Positive predictive values for basal CT levels in the preoperative diagnosis of MTC were: 23.1% for values more than or equal to 20 pg/ml, 100% for values more than 100 pg/ml, 25% for levels more than or equal to 50 and less than 100 pg/ml, and 8.3% for values more than or equal to 20 and less than 50 pg/ml. Positive predictive values for the pentagastrin test (>100 pg/ml) were 40% in the entire series.
  
  
  CONCLUSIONS
  CT screening of thyroid nodules is a highly sensitive test for early diagnosis of MTC, but confirmatory stimulation testing is necessary in most cases to identify true positive increases.
authors.affiliation: Dipartimento di Medicina Sperimentale e Clinica, Università Magna Graecia, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Costante
authors.forename: Domenico
authors.initials: D
authors.lastname: Meringolo
authors.forename: Cosimo
authors.initials: C
authors.lastname: Durante
authors.forename: Davide
authors.initials: D
authors.lastname: Bianchi
authors.forename: Maria
authors.initials: M
authors.lastname: Nocera
authors.forename: Salvatore
authors.initials: S
authors.lastname: Tumino
authors.forename: Umberto
authors.initials: U
authors.lastname: Crocetti
authors.forename: Marco
authors.initials: M
authors.lastname: Attard
authors.forename: Marianna
authors.initials: M
authors.lastname: Maranghi
authors.forename: Massimo
authors.initials: M
authors.lastname: Torlontano
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Filetti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D002116:Calcitonin / Q000097:blood*; D018276:Carcinoma, Medullary / Q000097:blood* / Q000175:diagnosis / Q000601:surgery; D002624:Chemistry, Clinical / Q000592:standards*; D002648:Child; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000097:blood / Q000175:diagnosis; D010418:Pentagastrin; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000592:standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000097:blood* / Q000175:diagnosis / Q000601:surgery; D016606:Thyroid Nodule / Q000097:blood* / Q000175:diagnosis / Q000601:surgery
chemical_list: D014408:Biomarkers, Tumor; D002116:Calcitonin; D010418:Pentagastrin