[The general rules for the study of pancreatic cancer from the viewpoint of internal medicine].

Useful nonsurgical treatments like chemoradiotherapy have been developed for the management of patients with unresectable pancreatic cancer. The General Rules for the Study of Pancreatic Cancer (Japan Pancreas Society) should therefore take diagnostic imaging techniques into account in order to deal with nonsurgical cases under the classification system as well as with surgical ones. The anatomic extent of disease based on preoperative dynamic CT images was evaluated in comparison with the results of pathology in a total of 35 patients with pancreatic cancer. The CT findings accurately represented the pathology for peripancreatic invasion, including vascular involvement, with a diagnostic accuracy ranging from 72% to 88%. However, it failed to detect almost half of lymphatic metastases. The staging of pancreatic cancer with dynamic CT was accurate in 66% of the patients, was underestimated in 25%, and was rarely overestimated. The detection of minute metastases is a crucial problem in the CT staging of tumors. The significant correlation of the RP factor (retroperitoneal tumor invasion) with lymphatic metastases as noted in this study offers a clue to solving this problem.