Evaluation of platelet distribution width as novel biomarker in gall bladder cancer.

INTRODUCTION: Gall bladder cancer (GBC) tends to present in advanced stages, therefore, early diagnosis of GBC is necessary. There is no ideal single tumor marker available presently for the diagnosis and prognosis of GBC. Platelet distribution width (PDW) is an early marker for activated platelets and has been used in a variety of tumors to assess prognosis. This study was designed to evaluate the utility of PDW in identifying GBC patients and its association with tumor markers, staging and resectability of GBC.

MATERIALS AND METHODS: This cross sectional study was done on 100 patients of GBC and 100 age- and sex- matched healthy controls. PDW was evaluated and compared between GBC and healthy controls. Receiver-operating characteristics was plotted to determine optimal cut-off for identifying GBC patients and to determine sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of PDW. Correlation between serum tumor markers (carbohydrate antigen 19-9, carcinoembryonic antigen, and carbohydrate antigen 125) and PDW were evaluated. Association of PDW with hyperbilirubinemia, staging and resectability of GBC was also studied.

RESULTS: A significantly higher PDW with a median of 18.1 was observed in GBC as compared to healthy controls with median value of 13. PDW was found to have a very high sensitivity (90%), specificity (95%), PPV (94%) and NPV (90%) in identifying GBC at cut-off of 16 with area under the curve (AUC) of 0.97. An increase of PDW was observed with increasing stage and unresectable GBC. However, it was not statistically significant. Significant positive correlation was observed between PDW and all three serum tumor markers and good positive correlation with r = 0.61 was observed with CA 19-9.

CONCLUSION: PDW was associated with GBC and may be considered as a cost- effective marker in adjunct to other investigations for the diagnosis of GBC.