S171 The Over-Estimation of Pancreatic Cyst Malignant Transformation Rates: A Lesson From the EPIC Cosmos Database

Introduction: The rate of pancreatic cysts transforming into pancreatic ductal adenocarcinoma (PDAC) is largely unknown, resulting in widely discrepant estimates of patient risk for malignancy. This discrepancy is largely due to reporting inherently biased surgical case series in patients with pancreatic cysts who develop PDAC from tertiary medical facilities. We employed a large database containing patient-specific diagnostic and procedural data to estimate the risk of malignant cyst transformation by focusing on patients who had definitive PDAC and pancreatic cysts. Methods: Epic Cosmos (Cosmos) was used for this this research study. Cosmos collates patient data from all hospitals systems utilizing the EPIC electronic medical record. Using the slicer-dicer tool, we evaluated the number of patients with PDAC who had cysts, and subsequently evaluated the number of patients with cysts who developed PDAC. We then compared these results in the context of the number of annual patients in the United States with PDAC. Results: There were 298,642,708 unique patients in the Cosmos database. A subpopulation of patients diagnosed with PDAC was isolated (n = 435,367). From this subpopulation, an additional subpopulation of those with an anytime diagnosis of pancreatic cyst was isolated (n = 50,482). Therefore, the ratio of patients with PDAC developing from cysts is at most approximately 11.6%. The inverse of the above isolation was performed from the initial patient population. The first subpopulation of those with pancreatic cyst were isolated (n = 782,665) and then sliced with the anytime diagnosis of PDAC subpopulation (n = 50,482), a rate of 6.5%. Assuming a widely-accepted 2.5% cyst rate in the population, 7,466,067 patients in this dataset would be expected to have cysts, yielding 866,064 PDAC based on the 11.6% malignant transformation rate. Conclusion: Using the Cosmos dataset, we demonstrated that the risk of malignant transformation from cysts to PDAC is vastly over-estimated. This is likely due to surgical case-series focusing on patients with cysts developing PDAC, rather than focusing on patients with PDAC who had cysts.