Carcinoembryonic Antigen Gradients Between Plasma and Malignant Ascites: Use in Detecting Peritoneal and Liver Metastases,

In the study of 19 patients with malignant ascites and elevated plasma carcinoembryonic antigen (CEA) (>2.5 ng/ml) and/or ascites CEA (>10 ng/ml), two patterns emerged: 1) The 10 patients with higher ascitic fluid than plasma CEA levels (medians: 230 and 10.6 ng/ml, respectively) had exudates and intraperitoneal cancer but usually had no hepatic metastases. 2) The 9 patients with lower ascitic fluid than plasma CEA levels (medians: 29 and 140 ng/ml, respectively) had transudates and negative cytology examinations but did have demonstrable liver metastases. Determination of ascitic fluid and plasma CEA gradients in patients with malignant ascites may help localize, with potentially therapeutic importance, the site of metastases.