Diagnostic value of chromogranin A in pancreatic neuroendocrine tumors depends on tumor size: A prospective observational study from a single institute

Background Chromogranin A has recently been recommended as the most practical tumor marker in patients with pancreatic neuroendocrine tumors. However, the diagnostic effectiveness of circulating chromogranin A levels remains controversial. Here, we aimed to assess the clinical diagnostic value of plasma chromogranin A levels for pancreatic neuroendocrine tumors. Methods Between June 2012 and June 2015, 110 consecutive patients with a suspected pancreatic neuroendocrine tumor were prospectively enrolled. We evaluated the diagnostic value of the chromogranin A assay for differentiating pancreatic neuroendocrine tumors from other tumors. The plasma chromogranin A levels in the pancreatic neuroendocrine tumor patients were examined according to various clinicopathologic factors. Results A total of 65 patients were diagnosed as having pancreatic neuroendocrine tumors, whereas 45 had other tumors. The median chromogranin A level in pancreatic neuroendocrine tumor cases was higher than that in cases of other tumors (pancreatic neuroendocrine tumors: 126.62 ng/mL, other tumors: 69.82 ng/mL). The sensitivity, specificity, and accuracy of the chromogranin A assay for pancreatic neuroendocrine tumor diagnosis were 49.2%, 77.8%, and 60.9%, respectively. The chromogranin A levels after operative resection were reduced or were confirmed as being within the normal range (78.9%) in most cases. Moreover, the chromogranin A level in pancreatic neuroendocrine tumors cases was correlated with tumor size based on comparisons with other tumors in the pancreas (P =.038). The sensitivity, specificity, and accuracy of the chromogranin A assay for large tumors were greater, at 64.3%, 100.0%, and 81.5%, respectively. Conclusion In clinical settings, the identification of pancreatic neuroendocrine tumors is vital for the development of therapeutic strategies. In large pancreatic tumors, the measurement of chromogranin A levels is very useful for distinguishing pancreatic neuroendocrine tumors from other tumors in the pancreas.