Serum and ascites chromogranin-A in patients with metastatic neuroendocrine tumors

Objectives: Ascites secondary to neuroendocrine tumor metastases may arise from a variety of mechanisms. Our aim was to measure serum and ascitic chromogranin-A (CgA) to help determine whether ascites resulted from intraperitoneal/retroperitoneal disease burden or from other carcinoid complications such as congestive heart failure or portal hypertension. Methods: Patients with metastatic neuroendocrine tumors and ascites were identified. Chromogranin-A was obtained and measured from both serum and ascites. The causes of carcinoid ascites was categorized into 2 groups: high intraperitoneal or retroperitoneal disease burden (ie, peritoneal metastases and/or lymphatic obstruction; n = 12, group 1) or other organ-specific carcinoid complications such as CHF or portal hypertension (n = 12, group 2). Results: An ascites CgA/serum CgA ratio greater than 1 was more likely to be found in group 1 (P = 0.01). This ratio produced 100% sensitivity and 75% specificity for ascites secondary to peritoneal metastases and/or lymphatic obstruction. Conclusions: An ascites CgA/serum CgA ratio greater than 1 produces excellent accuracy in predicting peritoneal metastases and/or retroperitoneal disease as the cause of ascites in the setting of metastatic carcinoid. This test may play a role in the earlier identification of those patients who may be well served by aggressive management.