Fibronectin, cholesterol and triglycerides ascitic fluid concentration in the prediction of malignancy

There have been few trials comparing the efficacy of determinations of cholesterol, fibronectin and triglycerides for diagnosis of malignant ascites. In this study we measured these in 200 ascitic fluids from 93 cirrhotic patients (Group A), 47 hepatocellular-carcinoma patients (Group B), 60 extra-hepatic tumour patients (Group C), 44 of them with malignant cells (Group Cpos) and 16 without (Group Cneg). Anova one-way and the Bonferroni test for multiple comparisons showed that fibronectin and cholesterol were significantly higher in the ascitic fluids of patients of group C than of groups A and B (mean ±ESM) (Cholesterol in A: 27.2±2.8; in B 23.5±1.5; in C: 68.6±5.3 mg/dl. Fibronectin in A: 32.7±2.8; in B 31.3±2.6; in C 127.7±11.1 mg/l). Both were significantly higher in Group Cpos than in Group Cneg (Cholesterol in Cneg: 41.2±6.7; in Cpos: 78.6±6.2 mg/dl. Fibronectin in Cneg: 55.0±11.2; in Cpos 154±12.3 mg/dl). We found no differences between cirrhotic ascites and malignant ascites due to primary liver hepatocellular-carcinoma. No differences at all in triglycerides were detected. With the Receiver-Operating Characteristic (ROC) curve, cholesterol had the best Youden Index (57%) at a cut-off of 32 mg/dl (sensitivity 78.3%, specificity 79.3% at this level); the best Youden Index (64%) for fibronectin had a cut-off of 60 mg/dl (sensitivity 65%, specificity 89.3%). Triglycerides appeared to be a great deal less effective as a diagnostic marker, with their best Youden Index (23%) at a cut-off 32 mg/dl (sensitivity 66.7%, specificity 56.4%). In conclusion, fibronectin and cholesterol appear to be reliable markers for diagnosis of malignant ascites due to extra-hepatic tumour, but their diagnostic accuracy is influenced by the presence or absence of malignant cells in the ascitic fluid. Since linear regression analysis showed strong correlation between the two tests, we think either can be used, but, in our opinion, cholesterol is to be preferred because of its better cost/benefit ratio. In addition, a step-wise discriminant analysis demonstrated that adding fibronectin to cholesterol increased the percentage to correctly classified cases by only 0.8% (from 79.5% to 80.3%).