Baseline and dynamic plasma chromogranin A (CgA) level to predict clinical outcome and tumor response in Asian patients with gastroenteropancreatic neuroendocrine tumor (GEP-NET).

Abstract

e15151 Background: The plasma CgA level is a reliable biomarker in diagnosing neuroendocrine tumors.The objective of this study is to correlate both the baseline value and the dynamic changes of plasma CgA level with disease status in Asian patients with advanced GEP-NET. Methods: Fifty-four patients with advanced GEP-NET were retrospectively evaluated between April 2010 and December 2012 in a single institution. Plasma CgA level and abdominal CT scan were obtained at diagnosis as a baseline and subsequently every 3 to 6 months after starting antitumor therapy.Statistical analysis of plasma CgA level was performed to predict the hazard ratio of clinical outcomes and also to correlate antitumor therapy responses with Response Evaluation Criteria in Solid Tumors Criteria 1.1. Results: Forty-six patients (85%) had elevated baseline CgA level. Twenty-one patients (39%) died at the end of the study with the medial follow-up duration of 292 days (range 12-992 days). Patients with baseline CgA level less than 2-fold of upper normal limit (UNL) had longer overall survival time than those with more than 2-fold of UNL (not reach vs. 272 days, hazard ratio = 0.39, 95% CI 0.15-0.99). Baseline CgA level less than 2-fold of UNL was still a favorable prognostic factor after adjusted for other variables (hazard ratio = 0.30, 95% CI 0.10-0.89). Twenty-eight patients with a total of 81 measurements of serial plasma CgA were available. An increase of plasma CgA level less than 15% predicted favorable antitumor response with a sensitivity of 86% and specificity of 91% (area under curve of receiving operating characteristics curves was 0.94). Conclusions: Baseline plasma CgA level and its dynamic change are useful values to predict clinical outcomes and antitumor responses in patients with GEP-NET.Baseline CgA level and serial measurements during antitumor therapy in patients with GEP-NET should be taken to assess their clinical outcomes.