Is extraluminal fluid (EFLUID) at endoscopic ultrasonography (EUS) an accurate marker of peritoneal carcinomatosis (PC)? A prospective study

Intro: In a few small retrospective series, detection of ascites by EUS is highly associated with PC in patients (pts) with gastric and pancreatic cancer. Aims: 1) To prospectively determine the prevalence of and associated risk factors for EFLUID. 2) To compare the accuracy of EUS and CT scan for the diagnosis of PC. Methods: In a prospective study, a single expert endosonographer noted the presence of any EFLUID in all EUS procedures performed over 12 months at an academic tertiary referral center. Patients with history of liver cirrhosis or advanced congestive heart failure were excluded. A final diagnosis of PC was made if peritoneal and/or omental implants and/or malignant ascites was proven by surgery or cytology. EUS and CT results were compared with final diagnoses. Bivariate analysis and multiple logistic regression were performed. Results: Of the 322 patients studied, 25 had EFLUID. It was present in 22 (13.5%) pts with malignant (n=163) and 3 (1.9%) pts with benign conditions (n = 155) (p<0.05). EFLUID was found in 40%, 33%, 5%, 3%, 0%, 25%, and 13% of 15 gastric, 21 pancreatic, 41 rectal, 63 esophageal, 5 duodenal/ampullary, 4 bile duct, and 15 non-GI cancers, respectively. EFLUID was more common in gastric, pancreatic, and bile duct cancers than in other tumors (p< 0.05). CT missed 69%. of PC (n = 13) and 68% of EFLUID (n = 25). EUS detected all but 3 patients with PC (all 3 CT negative); 2 were nontraversible cardia tumors and 1 was a gastric CA evident on review of videotape. In patients without PC, EFLUID was associated with advanced tumor stage (3), venous thrombosis/invasion (5), chronic pancreatitis (5), acute serositis and perigastric fat necrosis(1). In the multivariate model including tumor stage, EFLUID was the only significant independent predictor of PC (p=.03, odds ratio=10.5). The EUS accuracy was superior to CT in all pts, particularly in those with gastric cancer (80% vs. 50%, respectively, p<0.05). Conclusions: 1) Venous thrombosis/invasion and chronic pancreatitis are associated with the presence of EFLUID when PC is absent. 2) EFLUID is significantly more prevalent in gastric and pancreaticobiliary malignancies than in other tumors of the GI tract. 3) The presence of EFLUID is an excellent predictor of PC and is superior to CT in pts with gastric cancer.