ABO blood group distribution and risk of malignancy in patients undergoing resection for intraductal papillary mucinous neoplasm (IPMN).

BACKGROUND: The ABO blood type has been associated with risk of development of several malignancies, including pancreatic cancer. Data regarding IPMN is equivocal. To investigate this further, we analyzed the association between the ABO blood group and the presence of malignancy in a large cohort of resected IPMN and its influence in survival. METHODS: 819 patients who underwent pancreatic resection for IPMN in the Massachusetts General Hospital (MGH) and Cambridge University Hospitals NHS Foundation Trust (CUH) from January 1993 to December 2020 were identified from prospective institutional databases. Pathological characteristics and blood type were correlated. RESULTS: The distribution of blood types A, B, AB and O was 384 (47%), 92 (11%), 44 (5%) and 299 (37%), respectively. This blood type distribution was different than the reference population of the MGH and the CUH, which is 55% non-O blood group, and 45% type O. There was a significant predominance of non-O blood types when compared with O-blood type in patients with malignant IPMN (i.e. patients with high-grade dysplasia and invasive cancer) (67% vs 33%, OR 1.31 95%CI: 0.98-1.75, p = 0.069). The association was stronger for IPMN with invasive cancer (OR 1.43 95%CI: 1.01-2.02, p = 0.039). Blood group did not influence survival. CONCLUSION: Non-O blood type is associated with need for resection in IPMN and with presence of invasive carcinoma.