title: Plasma chromogranin A response to octreotide test: prognostic value for clinical outcome in endocrine digestive tumors.
abstract: OBJECTIVE
  Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) expressing somatostatin receptors may be treated with somatostatin analogs (SSAs). Selection criteria are a positive Octreoscan or a >50% hormone level decrease after octreotide subcutaneous (s.c.) injection (octreotide test) (OT). Plasma chromogranin A (CgA) is the best general GEP-NET marker, but data on CgA response to OT are scanty. Thus, we evaluated whether plasma CgA response to OT could predict the clinical response to SSAs.
  
  
  METHODS
  At diagnosis, 38 GEP-NET patients received octreotide 200 microg s.c., with plasma CgA determination at 0, 3, and 6 h. Long-term SSA treatment was then given by monitoring symptomatic, biochemical, and objective responses, and survival.
  
  
  RESULTS
  Basal plasma CgA levels were significantly higher in patients with functioning than non-functioning tumors (median (range): 220 (18-2,230) vs. 46 (25-8,610) U/l, P=0.03) and in those with than without metastases (171 (18-8,610) vs. 43 (28-220) U/l, P=0.04). CgA levels significantly correlated with WHO classification, clinical TNM staging, and Ki-67 proliferative index. After OT, CgA levels decreased from 146 (18-8,610) to 61 (10-8,535) U/l (basal and nadir values), P<0.001. In patients responsive to OT, a successful objective response occurred in 21/31 patients (68%). Successful symptomatic response occurred in 13/18 patients (72%), biochemical response in 25/31 (81%), and objective response in 21/31 (68%). In the remaining seven unresponsive cases, with CgA decrement <30%, disease progressed to death in six (86%). Median survival from enrollment was 48 months (6-138) in responsive and 6 (6-30) in unresponsive patients (P=0.0005).
  
  
  CONCLUSIONS
  In GEP-NETs, plasma CgA is a reliable marker, and a >30% decrease after OT has a relevant prognostic meaning allowing the identification of the subgroup of patients most likely to be responsive to chronic SSAs.
authors.affiliation: Gastroenterology Unit II, Fondazione IRCCS Policlinico, Mangiagalli e Regina Elena, Milan, Italy. sara.massironi@libero.it
authors.forename: Sara
authors.initials: S
authors.lastname: Massironi
authors.forename: Dario
authors.initials: D
authors.lastname: Conte
authors.forename: Valentina
authors.initials: V
authors.lastname: Sciola
authors.forename: Matilde Pia
authors.initials: MP
authors.lastname: Spampatti
authors.forename: Clorinda
authors.initials: C
authors.lastname: Ciafardini
authors.forename: Luca
authors.initials: L
authors.lastname: Valenti
authors.forename: Roberta Elisa
authors.initials: RE
authors.lastname: Rossi
authors.forename: Maddalena
authors.initials: M
authors.lastname: Peracchi
mesh_terms: D000328:Adult; D000368:Aged; D053379:Chromogranin A / Q000097:blood*; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000097:blood / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000097:blood / Q000175:diagnosis*; D015282:Octreotide; D010190:Pancreatic Neoplasms / Q000097:blood / Q000175:diagnosis*; D018579:Patient Selection; D011237:Predictive Value of Tests; D011379:Prognosis
chemical_list: D053379:Chromogranin A; D015282:Octreotide