CLINICAL VALUE OF CHROMOGRANIN A IN GASTROENTEROPANCREATIC NEUROENDOCRINE TUMORS

Abstract

Background: Neuroendocrine tumors (NET) is a heterogeneous group of neoplasms characterized by hypersecretion of biologically active sub- stances that manifests by specific syndromes and determines the clinical course of the disease. The most common NET types are those of gastrointestinal tract. The obligatory biochemical marker used in the examination of NET patients is chromogranin A (CgA). Aim: Evaluation of the CgA value for diagnostics and monitoring of gastrointestinal NETs. Materials and methods: A comparative study of plasma CgA levels was performed in 146 patients with gastroenteropancreatic neuroendocrine tu- mors and 66 healthy individuals using the enzyme immunoassay “Chromogranin A ELISA kit” (Dako A/S, Denmark). Results: CgA levels were significantly higher in patients with NETs of all localizations, such as pancreas, stomach, gut, small and large bowel, than in the healthy subjects (р < 0.000001). In NET patients, CgA secretion was highly variable, with the highest value in the group of patients with gastric NETs (102000 U/l). The highest CgA medians were detected in patients with small intestinal (183.9 U/l), colon (148.4 U/l) and pancreatic (135.9 U/l) NETs. There was an association between CgA secretion and extension or activity of NETs, with the highest median values in patients with hepatic metastases (395 U/l) and those with carcinoid syndrome (352 U/l). The clinical significance of CgA as a NET marker was assessed using the cut-off value of 33 U/l, calculated according to the results in the control group. Overall diagnostic sensitivity of CgA in NET patients was high (85.8%) with a specificity of 98.5%. Conclusion: The results obtained confirm a high sensitivity of CgA as a NET marker whose determination helps to improve accuracy of diagnostics and to assess NET prevalence.