The Diagnostic Value Of RCAS1-CEA Combined Detection In Malignant Pleural Effusion

Objective To investigate the diagnostic value of combined detection by receptor-binding cancer antigen expressed on SiSo cells (RCAS1) and carcinoembryonic antigen (CEA) in malignant pleural effusion.Methods Patients data were collected from confirmed24cases of malignant pleural effusion and29of benign pleural effusion from June2012to September2012. Enzyme linked immunosorbent assay (ELISA) was used to detect the levels of RCAS1in the serum and pleural effusion. CEA levels were measured by radio-immunity assay (RIA). The numbers of lymphocytes from peripheral blood were measured by automatic blood analyzer. It was applied that SPSS13.0statistical software. Nonparametric Mann-Whitney test was utilized for the analysis of two independent samples data. The data of multi-independent samples was analyzed by Kruskal-Wallis test. The results were showed by median and95%CI. The test data was analyzed and evaluated by receiver operating characteristic curve (ROC). The correlate between RCAS1and CEA in MPE was analyzed by spearman rank correlation. Values of P<0.05were considered to indicate statistical significance.Results The concentration of RCAS1(U/ml) in the malignant pleural effusion was significantly higher than that of the benign pleural effusion [12.490(10.196～35.883) vs4.222(3.881～6.284), P＜0.05]. There was no significant difference between the two serum groups [1.447(1.317～1.948) vs1.292(1.297～1.965), P＞0.05]. The levels of CEA (ng/ml/) were22.245(0～1100.442) and1.420(1.159～2.118) respectively in the malignant pleural effusion and benign pleural effusion. There was significant difference between the two pleural effusion groups (P＜0.05). The levels of CEA (ng/ml) were13.000(0～172.539) and2.040(1.717～3.102) respectively in the serum of malignant and benign groups. There was significant difference between the two serum groups (P＜0.05). The numbers of lymphocytes from peripheral blood (X10^9/L)were1.100(1.041～1.509)and1.080(0.979～1.315) respectively in the blood of malignant and benign groups. There was no significant difference between the two groups (P＞0.05). Diagnostic sensitivity and specificity value for RCAS1in malignant effusion were70.8%and86.2%respectively at the optimized diagnostic cut-off value of6.978U/ml,87.5%and96.6%for CEA at5ng/ml. The specificity could elevate to100%in series detection, sensitivity to95.8%in parallel detection. The concentration of RCAS1in malignant pleural effusion was no significant difference during the different age, gender, and histological type of tumor groups (P＞0.05). The correlation analysis resulted in no correlation between the concentration of RCAS1and CEA in malignant pleural effusion (rs=-0.05, P=0.818).Conclusion The detection of RCAS1has certain value for diagnosing the malignant pleural effusion. The combined testing of RCAS1and CEA can improve the sensitivity and specificity significantly. However the diagnostic value of RCAS1is not higher than that of CEA.