Purpose: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are relatively indolent but can be more aggressive. The current recommendations for the use of serum CgA for GEP-NET patients are equivocal. This study was designed to validate an automated CgA immunofluorescence assay for monitoring disease progression in GEP-NET patients. Patients and Methods: A prospective, multi-center blinded observational study was designed to validate an automated chromogranin A (CgA) immunofluorescence assay for monitoring disease progression in GEP-NET patients. Tumor progression was evaluated with Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 by CT/MRI. An increase ≥ 50% above the prior CgA concentration to a value > 100 ng/mL in the following CgA concentration was considered positive. Results: 153 GEP-NET patients were enrolled. Using the pre-specified cut-off of CgA change for tumor progression, specificity was 93·4% (95%-CI: 90·4%—95·5%, p < 0·001), sensitivity 34·4% (25·6%—44·3%), positive predictive value 57·9% (45·0—69·8), negative predictive value (NPV) 84·3% (80·5—87·6), and area under the curve 0·73 (0·67—0·79). Conclusions: Changes in serial measurements of serum CgA had a favorable specificity and NPV, making this test a useful adjunct to routine radiographic monitoring.

中文翻译：

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循环嗜糖粒蛋白 A 作为类癌患者的监测生物标志物 – CASPAR 研究


目的：胃肠胰神经内分泌肿瘤 （GEP-NETs） 相对惰性，但可能更具侵袭性。目前对 GEP-NET 患者使用血清 CgA 的建议是模棱两可的。本研究旨在验证用于监测 GEP-NET 患者疾病进展的自动化 CgA 免疫荧光测定。患者和方法： 一项前瞻性、多中心盲法观察性研究旨在验证自动嗜铬粒蛋白 A （CgA） 免疫荧光测定法用于监测 GEP-NET 患者的疾病进展。通过 CT/MRI 使用实体瘤反应评估标准 （RECIST） 1.1 评估肿瘤进展。在之前的 CgA 浓度上增加 50% ≥达到 > 100 ng/mL 的值被认为是阳性的。结果： 共纳入 153 例 GEP-NET 患者。使用预先设定的肿瘤进展 CgA 变化临界值，特异性为 93·4% （95%-CI： 90·4%—95·5%，p < 0·001），敏感性 34·4% （25·6%—44·3%），阳性预测值 57·9% （45·0—69·8），阴性预测值 （NPV） 84·3% （80·5—87·6），曲线下面积 0·73 （0·67—0·79）。结论： 血清 CgA 连续测量的变化具有良好的特异性和 NPV，使该测试成为常规影像学监测的有用辅助手段。