title: Concordance between results of somatostatin receptor scintigraphy with 111In-DOTA-DPhe 1-Tyr 3-octreotide and chromogranin A assay in patients with neuroendocrine tumours.
abstract: OBJECTIVE
  Somatostatin receptor scintigraphy (SRS) and chromogranin A (CgA) assay have successfully been implemented in the clinical work-up and management of neuroendocrine tumour (NET) patients. However, there is still a lack of studies comparing results in these patients. Our aim was to compare directly in NET patients SRS and CgA assay results with special regard to tumour features such as grade of malignancy, primary origin, disease extent and function.
  
  
  METHODS
  One hundred twenty consecutive patients with histological confirmed NETs were investigated with (111)In-DOTA-DPhe(1)-Tyr(3)-octreotide ((111)In-DOTA-TOC) SRS and CgA immunoradiometric assay. Tumours were classified by cell characteristics [well-differentiated NETs, well-differentiated neuroendocrine carcinomas, poorly differentiated neuroendocrine carcinomas (PDNECs)], primary origin (foregut, midgut, hindgut, undetermined), disease extent (limited disease, metastases, primary tumour and metastases) and functionality (secretory, nonsecretory).
  
  
  RESULTS
  SRS was positive in 107 (89%) patients; CgA levels were increased in 95 (79%) patients. Overall, concordance between SRS and CgA results was found in 84 patients. Positive SRS but normal CgA level were found in 24 patients, with higher prevalence (p<0.05) in patients with nonsecretory tumours. Conversely, negative SRS but CgA level increased were seen in 12 patients, with higher proportion (p<0.05) in patients with PDNECs and tumours of hindgut origin.
  
  
  CONCLUSIONS
  Overall, (111)In-DOTA-TOC SRS proved to be more sensitive than CgA in NETs patients. Tumour differentiation, disease extent and presence of liver metastases impact both SRS and CgA results, whereas nonsecretory activity is a negative predictor of only CgA increase. PDNECs and hindgut origin of tumours predispose to discrepancies with negative SRS but increased CgA levels.
authors.affiliation: Department of Nuclear Medicine, Medical University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria. rodriguesradischat@hotmail.com
authors.forename: Margarida
authors.initials: M
authors.lastname: Rodrigues
authors.forename: Michael
authors.initials: M
authors.lastname: Gabriel
authors.forename: Dirk
authors.initials: D
authors.lastname: Heute
authors.forename: Daniel
authors.initials: D
authors.lastname: Putzer
authors.forename: Andrea
authors.initials: A
authors.lastname: Griesmacher
authors.forename: Irene
authors.initials: I
authors.lastname: Virgolini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood*; D053379:Chromogranin A / Q000097:blood*; D006801:Humans; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging* / Q000378:metabolism*; D015282:Octreotide / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D017481:Receptors, Somatostatin / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: C507387:111In-DOTA-TOC; D014408:Biomarkers, Tumor; D053379:Chromogranin A; D019275:Radiopharmaceuticals; D017481:Receptors, Somatostatin; D015282:Octreotide