Preoperative staging
Arterial invasion was defined as any direct tumor-to-vessel contiguity (contact with complete obliteration of the fat plane) even if contact is less than 50%
Venous invasion was defined as tumor-to-vessel circumferential contiguity >= 50%.
Liver metastases were nodular low attenutation lesions >= 1 cm in diameter which could not be identified to be a cyst or hemangioma.
Lymph nodes > 1.5 cm outside peripancreatic draining chains of the pancreas were considered malignant.
Peritoneal dissemination was diagnosed if there was substantial ascites and a large number of peritoneal nodules.
Criteria for unresectability - one or more of the following:
(1) liver metastasis
(2) metastases to regional or distant lymph nodes
(3) metastases to the omentum
(4) invasion of an adjacent organ excludng the duodenum
(5) arterial invasion or any tumor-to-artery contiguity
(6) massive venous invasion (tumor thrombus, obliteration of venous lumen)
(7) peritoneal dissemination
In 2002 the positive predictive value of resectability was 77% using dual-phase helical CT..
Reasons for unresectability that were not detected on the CT scan:
(1) small hepatic metastases
(2) vascular encasement/arterial invasion
(3) lymph node metastases
