RT Journal Article SR Electronic T1 Efficacy of Adjuvant Chemotherapy According to the Pathological Response to Neoadjuvant Chemotherapy Among Patients With Pancreatic Ductal Adenocarcinoma JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 1629 OP 1639 DO 10.21873/anticanres.14925 VO 41 IS 3 A1 SHOZO MORI A1 TAKU AOKI A1 YUHKI SAKURAOKA A1 TAKAYUKI SHIMIZU A1 TAKAMUNE YAMAGUCHI A1 KYUNG-HWA PARK A1 TAKATSUGU MATSUMOTO A1 TAKAYUKI SHIRAKI A1 YUKIHIRO ISO A1 KEIICHI KUBOTA YR 2021 UL http://ar.iiarjournals.org/content/41/3/1629.abstract AB Background/Aim: An association between the pathological response to neoadjuvant chemotherapy (NAC) and the efficacy of adjuvant chemotherapy (AC) in patients with pancreatic ductal adenocarcinoma (PDAC) remains unknown. Patients and Methods: A total of 121 patients with PDAC who underwent a pancreatectomy between January 2013 and March 2020 were divided into two groups: an upfront surgery (UFS) group (n=42), and an NAC (gemcitabine plus S-1) group (n=79). In the NAC group, the pathological response was evaluated using the Evans classification. Results: The overall survival was significantly higher in patients with an AC relative dose intensity (RDI) ≥80% than in patients with an AC RDI <80% in the UFS, NAC-Evans IIa, and NAC-Evans IIb+III groups. However, this difference was not observed in the NAC-Evans I group. Conclusion: AC is preferable for patients with NAC-Evans IIa or IIb+III, but more effective AC regimens may be needed for NAC-Evans I patients.