Comparison of platelet-lymphocyte ratio and CA 19-9 in differentiating benign from malignant head masses in patients with chronic pancreatitis.

INTRODUCTION

Pancreatic head ductal adenocarcinoma (PDAC) and inflammatory head masses (IHM) related to chronic pancreatitis are often difficult to differentiate. PDAC produces significant inflammatory response with resultant lymphopenia and thrombocytosis. The prognostic role of platelet-lymphocyte ratio (PLR) as a tumor marker has been defined. We aimed to find the role of PLR as a diagnostic marker for PDAC in differentiating benign head mass comparing with carbohydrate antigen 19-9 (CA 19-9).

METHODS

A prospective study of patients with biopsy-proven PDAC and benign IHM with underlying chronic pancreatitis from 1st November 2014 to 30th June 2016 was performed. Total blood count including platelet count and CA 19-9 were recorded and statistically analyzed.

RESULTS

There was no significant difference in total leukocyte counts (7789±2027 vs. 7568±1289 cells/mm) between PDAC (n = 34) and IHM (n = 27). However, the mean lymphocyte (2235±837 vs. 2701±631 cells/mm) and platelet counts in mm (3.36±0.789) × 10 vs. (2.45±0.598) × 10 showed difference. The median PLR was 161.9 (IQR = 117.5-205.6) in PDAC and 91 (IQR = 77.2-106.6) in IHM. The median CA 19-9 (U/mL) in PDAC and IHM was 69.3 (IQR = 22.7-427.7) and 13.9 (IQR = 7.2-23.6), respectively. On plotting the receiver operator characteristic curve (ROC curve), area under the curve was maximum for PLR (88.7%) compared to CA 19-9 (77.8%) in diagnosing PDAC (p<0.0001). Using coordinates of ROC, PLR cutoff value was 113.5 (sensitivity-79.4%, specificity-92.6%, positive predictive value (PPV)-91.5%, negative predictive value (NPV)-99.7%) while CA 19-9 cutoff value was 25.3 U/mL (sensitivity-73.5%, specificity-77.8%, PPV-78.5%, NPV-74.6%).

CONCLUSION

PLR may be useful to differentiate PDAC from benign IHM in patients with chronic pancreatitis.