Low accuracy of chromogranin A for diagnosing early-stage pancreatic neuroendocrine tumors

The aim of the present study was to evaluate the clinical utility of plasma chromogranin A (CgA) in patients diagnosed with early-stage pancreatic neuroendocrine tumors (PNETs) in terms of diagnostic value and treatment response. A total of 35 patients with PNETs were prospectively enrolled from August 2010 to April 2014. Demographic and clinicopathological data were collected, and serial plasma CgA levels were measured. Tumor responses were defined by the Response Evaluation Criteria In Solid Tumors criteria. Pearson's χ2 test was used for the analysis of the association between the plasma CgA level and various factors. Plasma CgA level was significantly associated with the size (P=0.03), metastasis (P=0.02) and tumor stage (P=0.03) of the PNETs. Using 126 U/l as the optimal cutoff value, the sensitivity and specificity were 87.5 and 81.5%, respectively. For localized tumors, the sensitivity of CgA for diagnosing PNETs was relatively low, even following a lowering of the cutoff values (29.6–51.9%). Plasma CgA level was correlated with therapeutic response in those patients with high baseline CgA levels (P=0.025), but not in the patients with low baseline CgA levels (P=0.587). In conclusion, plasma CgA level was associated with tumor size, metastasis and tumor stage in patients with PNET. For early-stage PNETs, CgA exhibited a limited role in diagnosis and treatment response evaluation in the population of the present study.