Ascitic Fluid Fibronectin: A Marker to Differentiate Between Malignant and Non-malignant Ascites

Background and Aims: So far, the differentiation between malignant and non-malignant ascites by laboratory parameters has not been fully achieved yet. Fibronectin is a glycoprotein which plays an important role in cell adhesion, growth, migration, and differentiation. The aim of the study was to assess the accuracy of fibronectin for the diagnosis of malignant ascites and to compare it with conventional use of cytology.
Study Design: A cross sectional study to determine the correlation between ascitic fluid fibronectin and malignant and non-malignant ascites.
Place and Duration of Study: This study was carried out at the clinics of gastroenterology, surgery, and obstetrics/gynecology at the Lagos University Teaching Hospital (LUTH), between August 2011 and July 2013.
Methods: Ascitic fluid and serum samples from 75 patients were taken. 37 of them (7 males and 30 females) had malignancy-related ascites (Group 1), while the other 38 (18 males and 20 females) had non-malignant ascites (Group 2) respectively. These were analysed for fibronectin, lactate dehydrogenase (LDH), total protein, and albumin. Cytology was also done for all ascitic fluid samples.
Results: Mean values of ascitic fluid fibronectin and LDH were higher in malignancy-related ascites (97.5 µg/ml, and 900.60 IU/L) respectively than in non-malignant ascites (47.7 µg/ml, and 199.31 IU/L) respectively (P less than 0.001). Ascitic fluid fibronectin with a cut-off value of 73 µg/ml gave the best diagnostic accuracy with a sensitivity and specificity of 94.7% and 94.6% respectively, while ascitic fluid LDH with a cut-off value of 310 IU/L gave diagnostic accuracy with a sensitivity and specificity of 97.3% and 84.2% respectively. The mean total protein level in the malignant group was 38.72±18.00 g/L and 30.21±15.00 g/L for the non-malignant group. The mean albumin levels were 28.08±10.32 g/L and 31.23±10.01 g/L for the malignant and non-malignant groups respectively. For both total protein and albumin, the P value was statistically insignificant. In this study, cytology yielded a sensitivity of 56.8% and a specificity of 100%.
Conclusion: The results of this study suggest that fibronectin concentration in ascitic fluid may be useful in differentiating malignant from non-malignant ascites and could supplement cytology in the differential diagnosis of ascites. Further studies are needed to confirm these results.