Interest of Chromogranin A for diagnosis and follow-up of endocrine tumours.
OBJECTIVE
To determine the interest of Chromogranin A (CgA) determination for diagnosis and follow-up in patients with gastroenteropancreatic endocrine tumours (GEP-ET) and multiple endocrine neoplasia type 1 (MEN-1).


METHODS
CgA levels were measured with an immunoradiometric assay in 124 sporadic GEP-ET, 34 MEN-1 and 127 controls. Serial determinations were performed in 56 patients (212 visits). Changes in CgA levels over 25% were considered as significant.


RESULTS
Using a cut-off value of 130 micro g/l, established from a receiver-operating characteristic curve, the specificity of CgA was 98.4%, with a sensitivity of 62.9%, higher in secreting than in nonsecreting tumours (73%vs. 45%; P < 0.003) and related to the extent of metastatic spreading (P < 0.001). In nonsecreting tumours, the positive predictive value (PPV) of CgA for the presence of metastases was 100% but the negative predictive value (NPV) was only 50%. In MEN-1, high CgA levels indicated a pancreatic tumour with a 100% specificity but the sensitivity was 59%. During the follow-up, the concordance between CgA and tumour evolution was 80%, whatever the secretory status. In patients with carcinoid tumours, the concordance was higher for CgA than for serotonin (81%vs. 54%; P < 0.001).


CONCLUSIONS
Due to its high specificity, CgA determination may help to discriminate the endocrine character of a GEP tumour and to indicate a pancreatic tumour in MEN-1. However, its low NPV in nonsecreting tumours limits its interest for diagnosis and staging. By contrast, serial evaluation of CgA seems of particular interest for the follow-up of GEP-ET tumours.
Nehar
D
D
Service de Radioanalyse and Centre de Médecine Nucléaire, Hôpital Neuro-cardiologique, Hopital Edouard Herriot, Lyon, France.
Lombard-Bohas
C
C
Olivieri
S
S
Claustrat
B
B
Chayvialle
J-A
JA
Penes
M-C
MC
Sassolas
G
G
Borson-Chazot
F
F
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D053379:Chromogranin A; D002864:Chromogranins / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015592:Immunoradiometric Assay / Q000379:methods; D008297:Male; D008875:Middle Aged; D018761:Multiple Endocrine Neoplasia Type 1 / Q000097:blood / Q000175:diagnosis*; D010190:Pancreatic Neoplasms / Q000097:blood / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000097:blood / Q000175:diagnosis*
D015415:Biomarkers; C506150:CHGA protein, human; D053379:Chromogranin A; D002864:Chromogranins