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

Abstract

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 cancer, 16 (6%) Merkel cell carcinoma and 6 parathyroid NETs, pheochromocytoma, paraganglioma. Only 26% of GEP tumors presented with specific symptoms. At the entry in the study 58% of patients had a new diagnosis, 23% were in stable disease, whereas 18% had metastatic disease. According to the recent W.H.O. histologic classification (Solcia et al, 2000), 36% specific symptomatic patients had NE tumor, 57% well differentiated cancer and only 3% poor differentiated cancer, whereas 31% not symptomatic patients had NE tumor, 48% well differentiated and 16% poor differentiated cancer. This is the largest study worldwide performed on this topic and all the data about the correlation among all patient variables and CgA blood values will be ready in April 2006. Follow-up data will be evaluable next year. [Table: see text]