Mobilization of malignant ascites with diuretics is dependent on ascitic fluid characteristics.

Serial ascites and plasma volumes were measured during diuresis in nine patients with ascites caused by peritoneal carcinomatosis, four patients with chylous malignant ascites, and three patients with portal hypertension-related ascites caused by massive hepatic metastases. Oral diuretics were given to achieve an adequate natriuresis on a sodium-restricted diet. During the study period (7.8 +/- 3.2 days), patients with peritoneal carcinomatosis and chylous ascites lost 0.49 +/- 0.31 and 0.51 +/- 0.42 kg/day in weight, respectively, with negligible change in ascites volumes (-0.03 +/- 0.11 and 0.02 +/- 0.09 L/day). Patients with ascites caused by massive hepatic metastasis lost 1.06 +/- 0.15 kg/day in weight (P = 0.01 for massive hepatic metastasis vs. peritoneal carcinomatosis) and 0.23 +/- 0.13 L/day of ascites (P less than 0.05 vs. other groups). Plasma volume changes were not significantly different among the three groups. Patients with edema (9/16) had a greater natriuresis and daily weight loss. Three patients with peritoneal carcinomatosis and one with chylous ascites developed renal dysfunction or symptomatic hypotension. No patient with massive hepatic metastasis developed these complications. In patients with ascites caused by peritoneal carcinomatosis or chylous malignant ascites there is no mobilization of ascites, whereas in patients with massive hepatic metastasis, ascites may be mobilized with diuretics.