2. Only untreated patients with high risk pancreatic adenocarcinomas will be eligible for the study. For this study, such patients are defined as those who meet one or more of the following radiographic or serologic criteria: a)Primary tumor that involves the superior mesenteric vein causing a vein deformity or segmental venous occlusion with a patent vessel above and below suitable for reconstruction. b)Primary tumor that involves </= 180 degrees of the superior mesenteric artery (SMA), celiac axis or any of its branches on CT or MRI. c) Primary tumor that abuts or encases (>/= 50% of the vessel circumference) a short segment of the common hepatic artery (typically at the gastroduodenal artery origin)