How to increase the diagnostic value of malignancy-related ascites: discriminative ability of the ascitic tumour markers.

Making a differential diagnosis between malignant and non-malignant ascites is an important clinical issue, but cytological examination has a relatively low diagnostic sensitivity. This study aimed to find a discriminative model that distinguished between malignancy-related and non-malignant ascites. The study included 107 patients: 50 with non-malignant and 57 with malignant ascites. Ascites was analysed using a range of tumour markers and standard cytology. Standardized canonical discriminant function coefficients were used to distinguish between ascites types. The combination of carbohydrate antigen (CA) 15-3, carcinoembryonic antigen (CEA) and cytokeratin 19 fragments (CYFRA-21.1) discriminated between malignancy-related ascites and non-malignant ascites with an accuracy of 98.8% compared with an accuracy of 77.8% for cytological examination. In conclusion, the use of a discriminant function constructed from a combination of CA15-3, CEA and CYFRA-21.1 could distinguish malignant from non-malignant ascites with greater accuracy than cytological examination. Further studies in larger population groups are warranted.