Comparison of diagnostics power of chromogranin A elisa test in general population of patients with neuroendocrine tumors and with metastases

Neuroendocrine tumours (NET) are a rare and heterogeneous group of neoplasms derived from neuroendocrine cells scattered in the body. These cells mainly produce numerous peptides and biogenic amines i.e. chromogranin A. Despite many limitations CgA has been successfully used in the diagnosis of NET. It is a well-recognized marker for treatment monitoring and prognosis of disease course for patients diagnosed with NET. The purpose of this study was to evaluate the diagnostic usefulness of CgA Elisa test in the group of patients with NET and in selected groups of patients with metastases. The evaluation was performed in the group of 70 patients diagnosed with NET and 52 (74%) of them had confirmed metastases, 18 (26%) had no metastases detected. In order to investigate the diagnostic usefulness of serum CgA we plotted ROC curves (Receiver Operating Characteristic) and area under the curve (AUC) was calculated. Sensitivity, specificity, positive and negative predictive values were calculated using the standard equations for CgA cut-off set at 19 U/l obtaining values of 67%, 85%, 89%, 55% respectively. We also evaluated diagnostics power of CgA evaluation in selected groups of patients: with metastases to the liver and/or bone, lung, brain, lymph nodes. Diagnostics sensitivity of CgA in this group was 89%, however in the group of patients with metastases to the lymph nodes and distant organs reached the level of 75%. We conclude that the ELISA test from DacoCytomation for the determination of chromogranin A in serum used in this study has a good diagnostic power in detecting neuroendocrine tumors.