Interest of Chromogranin A for diagnosis and follow-up of endocrine tumours
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). patients and 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 µg/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). conclusion
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.
Document Type: Research Article
Affiliations: 1: Service de Radioanalyse and Centre de Médecine Nucléaire, Hôpital Neuro-cardiologique and 2: Fédération des Spécialités Digestives and Laboratoire de Biochimie, Hôpital Edouard Herriot, Lyon, France
Publication date: May 1, 2004