Between February 2005 and October 2010, 100 patients with PDAC who were diagnosed as having UICC-T3 and UICC-T4 tumors using multidetector computed tomography (MDCT) were enrolled for our gem-CRTS protocol. All patients were warned of the risks of treatment, especially concerning the possibility of developing distant metastases after gem-CRT treatment. They all gave their written informed consent for inclusion in the study. The diagnosis of pancreatic cancer was confirmed by means of cytological or histological analysis of biopsy specimens obtained using endoscopic ultrasonography–guided fine-needle aspiration (EUS-FNA). Patients were excluded when the tumor extension determined by MDCT was categorized as UICC-T1 or UICC-T2 and/or when they showed evident distant metastatic lesions. The study protocol was approved by the medical ethics committee of Mie University, and the study was performed in accordance with the ethical standards established in the 1964 Declaration of Helsinki.
All patients underwent pretreatment examination using a 64-slice MDCT. Computed tomography (CT) was performed according to a defined pancreas protocol as 4-phasic contrast-enhanced MDCT with thin slices at intervals of 1 mm. In the present study, all of these 100 patients were reclassified into the 3 groups (R, BR, and UR) according to NCCN guidelines (2010)7 based on MDCT findings at the initial visit to our hospital. The CT criteria of the NCCN guidelines are as follows: R criteria, (1) no evidence of SMV and PV abutment, distortion, tumor thrombus, or venous encasement and (2) clear fat planes around the CA, hepatic artery, and SMA; BR criteria, (1) venous involvement of the PV/SMV demonstrating tumor abutment without impingement and narrowing of the lumen, encasement of the PV/SMV without encasement of the nearby arteries, or short-segment venous occlusion resulting from either tumor thrombus or encasement but with suitable vessel proximal and distal to the area of vessel involvement, allowing for safe resection and reconstruction, (2) gastroduodenal artery encasement up to the hepatic artery with either short-segment encasement or direct abutment of the hepatic artery without extension to the CA, and (3) tumor abutment of the SMA not exceeding greater than 180° of the circumference of the vessel wall; and UR criteria, (1) greater than 180° of SMA encasement, celiac involvement (any abutment of the head with a greater than 180° encasement of the body or tail), (2) unreconstructive PV/SMV occlusion, and (3) aortic invasion. On the basis of the objective CT criteria, the patients enrolled in our study were classified as follows: 14 patients with R, 44 with BR, and 42 with UR tumors.