Abnormal serum pancreatic enzymes, but not pancreatitis, are associated with an increased risk of malignancy in patients with intraductal papillary mucinous neoplasms.

INTRODUCTION

Pancreatitis is associated with intraductal papillary mucinous neoplasm (IPMN). This association is in part due to inflammation from pancreatic ductal obstruction. Although the correlation between pancreatitis and the malignant potential of IPMN is unclear, the 2012 International Consensus Guidelines (ICG) consider pancreatitis a "worrisome feature." We hypothesized that serum pancreatic enzymes, markers of inflammation, are a better predictor of malignancy than pancreatitis in patients with IPMN.

METHODS

Between 1992 and 2012, 364 patients underwent resection for IPMN at a single university hospital. In the past decade, serum amylase and lipase were collected prospectively as an inflammatory marker in 203 patients with IPMN at initial surveillance and "cyst clinic" visits. The latest serum pancreatic enzyme values within 3 months preoperatively were studied. Pancreatitis was defined according to the 2012 revision of the Atlanta Consensus.

RESULTS

Of the 203 eligible patients, there were 76 with pancreatitis. Pancreatitis was not associated with an increased rate of malignancy (P = .51) or invasiveness (P = .08). Serum pancreatic enzymes categorically outside of normal range (high or low) were also not associated with malignancy or invasiveness. In contrast, as a continuous variable, the higher the serum pancreatic enzymes were, the greater the rate of invasive IPMN. Of the 127 remaining patients without pancreatitis, serum pancreatic enzymes outside of normal range (low and high) were each associated with a greater rate of malignancy (P < .0001 and P = .0009, respectively). Serum pancreatic enzyme levels above normal range (high) were associated with a greater rate of invasiveness (P = .02).

CONCLUSION

In patients with IPMN without a history of pancreatitis, serum pancreatic enzymes outside of the normal range are associated with a greater risk of malignancy. In patients with a history of pancreatitis, there is a positive correlation between the levels of serum pancreatic enzymes and the presence of invasive IPMN. These data suggest serum pancreatic enzymes may be useful markers in stratification of pancreatic cancer risk in patients with IPMN.