- The primary tumor must be resectable, defined as no involvement (abutment or encasement) of the major arteries (celiac, common hepatic, superior mesenteric) and interface between tumor and vessel (portal, superior mesenteric veins) wall to be less than 180 degrees of the circumference of the vessel wall; this should be confirmed by imaging of the abdomen, either by a contrast-enhanced computed tomography (CT) scan, or a contrast-enhanced magnetic resonance imaging (MRI) scan; PET scans will not be adequate alternatives; for each patient, the resectability must be reviewed by one of the study surgeons