High serum carbohydrate antigen 125 concentration can predict serous effusion but not gastrointestinal malignancy in male patients

This study aims to evaluate the diagnostic accuracy of carbohydrate antigen 125 (CA125) in male patients for predicting gastrointestinal malignant diseases. One hundred twenty consecutive male patients underwent CA125 test after admission to the Department of Gastroenterology in Changhai Hospital, the Second Military Medical University, from April to June 2013. Data of age, main symptoms, and final diagnosis were summarized. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) of CA125 for malignancy were estimated, and the receiver operating characteristic (ROC) analysis and the area under the curve (AUC) were also performed to evaluate the diagnostic value of CA125 in male patients. The PPV, NPV, PLR, and NLR of CA125 in malignancy were 55 %, 69 %, 1.90, and 0.71, respectively. However, we found that an elevated serum CA125 level was more common in male patients with serous effusion than those with malignancy. The PPV, NPV, PLR, and NLR of CA125 in serous effusion were 85 %, 96 %, 12.70, and 0.09, respectively. In the ROC analysis, the AUC values for CA125 was 0.96 (95 % confidence interval, 0.93–0.99) for discriminating patients with serous cavity effusion from those without serous effusion. CA125 has a higher accuracy in detecting serous effusion than malignancy in male patients with gastrointestinal diseases. It is of little significance for male patients to perform CA125 test for malignancy.