Circulating chromogranin-a (CgA) as a useful marker in the diagnosis and follow up of neuroendocrine tumors (nets): An Italian multicenter observational study (cromAnet)

14091 The primary objective of this study was to validate the clinical significance of blood evaluation of CgA in NET patients at the diagnosis (PHASE I) and during 2 years of follow-up (PHASE II). From May 2003 to October 2004, 276 patients entered the study from 40 Italian centers: 270 were evaluable. All basal and every 3 months collected CgA blood samples were centrally measured in two reference laboratories (Orbassano-Turin and Venice) where ELISA (DAKO,Denmark) or IRMA (CIS-Schering, France) were performed to look at the correlation between the two methods and their sensitivity and specificity. Lab results at the baseline have been recently published (Leon et al., Intern. J. Biol. Markers, 2005). We are now collecting all the correlations between CgA and type and place of NETs; tumor bulk; metastatization; presence or not of specific syndrome;proliferation activity (Ki67); octreoscan; tumor specific markers. 223 patients (83%) had gastroenteropancreatic tumors, whereas 24 (9%) had medullary tyroid c...