Blood Type as a Predictor of High-Grade Dysplasia and Associated Malignancy in Patients with Intraductal Papillary Mucinous Neoplasms.

BACKGROUND: Intraductal papillary mucinous neoplasms (IPMNs) are precursor lesions to the development of pancreatic adenocarcinoma. We determined if non-O blood groups are more common in patients with IPMN and if blood group is a risk factor for progression to invasive pancreatic cancer among patients with IPMN. METHODS: The medical records were reviewed of all patients undergoing resection of an IPMN at Johns Hopkins Hospital from June 1997 to August 2016. Potential risk factors of high-grade dysplasia and associated adenocarcinoma were identified through a multivariate logistic regression model. RESULTS: Seven hundred and seventy-seven patients underwent surgical resection of an IPMN in which preoperative blood type was known. Sixty-two percent of IPMN patients had non-O blood groups (vs. 57% in two large US reference cohorts, P = 0.002). The association between non-O blood group was significant for patients with IPMN with low- or intermediate-grade dysplasia (P < 0.001), not for those with high-grade dysplasia (P = 0.68). Low- and intermediate-grade IPMNs were more likely to have non-type O blood compared to those with high-grade IPMN and/or associated invasive adenocarcinoma (P = 0.045). Blood type O was an independent predictor of having high-grade dysplasia without associated adenocarcinoma (P = 0.02), but not having associated invasive cancer (P = 0.72). The main risk factor for progression to invasive cancer after surgical resection was IPMN with high-grade dysplasia (P = 0.002). CONCLUSION: IPMN patients are more likely to have non-O blood groups than controls, but type O blood group carriers had higher odds of having high-grade dysplasia in their IPMN. These results indicate blood group status may have different effects on the risk and progression of IPMNs.