CA 19-9 to differentiate benign and malignant masses in chronic pancreatitis: is there any benefit?

Background The role of the tumor marker CA 19-9 in differentiating benign from malignant masses in chronic pancreatitis has not been extensively studied. Aim This study aims at assessing the accuracy of CA 19-9 in differentiating inflammatory head masses in chronic pancreatitis from superimposed carcinomas on chronic pancreatitis. Methods The data of 84 consecutive patients who had mass lesions in chronic pancreatitis were analyzed to determine the sensitivity, specificity and predictive values at cut-off values of 37, 100, 200 and 300 U/mL. Receiver operating characteristic (ROC) curves were used to assess the sensitivity and specificity. Results There were 50 benign masses and 34 malignancies. The overall sensitivity and specificity of CA 19-9 for cancer was 68% and 70%, respectively. There was a higher positivity of CA 19-9 in cancers than in benign masses (23/34; 68% versus 15/50; 30%, P < 0.01) with cut-off values of 37 U/mL. Higher positivity rates were obtained in cancers using other cut-off values such as 100, 200 and 300 U/mL. Values over 300 U/mL were 100% specific for malignancy, but occurred in only 5 (of whom had distant metastases) of 34 patients. Conclusion CA 19-9 level in excess of 300 U/mL in mass lesions in chronic pancreatitis was always indicative of malignancy.