Objectives: Pancreatic ductal adenocarcinoma (PDAC) may derive from an intraductal papillary mucinous neoplasm (IPMN) of the pancreas or may develop in the pancreatic duct apart from IPMN. The purpose of this study was to define the clinicopathological features of these 2 entities and compare them with those of ordinary PDAC.
Methods: Of 765 patients who had surgical resection for IPMN, 122 were diagnosed as having PDAC derived from IPMN and 31 with PDAC concomitant with IPMN. In addition, 7605 patients with PDAC who were registered in the Japan Pancreas Society pancreatic cancer registry were compared with the above patients.
Results: Pancreatic ductal adenocarcinomas derived from IPMN and concomitant with IPMN were significantly smaller, less invasive, and less extensive than ordinary PDAC. The median survival of patients with the 2 conditions was significantly longer than for those with ordinary PDAC when compared overall or when limited to TS2 (2.0 cm < tumor size ≤ 4.0 cm) or TS3 (4.0 cm < tumor size ≤ 6.0 cm) cases.
Conclusions: These findings suggest that PDAC concomitant with IPMN and PDAC derived from IPMN may have more favorable biological behaviors or be diagnosed earlier than ordinary PDAC.