Yoshito Tomimaru, Hidetoshi Eguchi, Yosuke Inoue, Yuichi Nagakawa, Akihiro Ohba, Hideki Takami, Michiaki Unno, Tomohisa Yamamoto, Shoji Kawakatsu, Tsuyoshi Hayashi, Ryota Higuchi, Hirohisa Kitagawa, Satoshi Hattori, Tsutomu Fujii, Yoshiki Hirooka, Hisato Igarashi, Masayuki Kitano, Tamotsu Kuroki, Atsushi Masamune, Yasuhiro Shimizu, Masaji Tani, Satoshi Tanno, Yoshihisa Tsuji, Hiroki Yamaue, Sohei Satoi, Yoshifumi Takeyama
Cancer 129(5) 728-739 2023年3月1日
BACKGROUND: Based on the Japan Adjuvant Study Group of Pancreatic Cancer 01 study, the standard duration of adjuvant chemotherapy with S-1 (an oral 5-fluorouracil prodrug consisting of tegafur, gimeracil, and oteracil) in patients with resected pancreatic ductal adenocarcinoma (PDAC) was considered to be 6 months, but the impact of increasing its duration on postoperative survival was unknown. Here, the authors investigated this question by reviewing real-world data from a large cohort of patients with PDAC. METHODS: In total, 3949 patients who underwent surgery for PDAC during the study period followed by S-1 adjuvant chemotherapy in board-certified institutions were included. Based on the duration of S-1 chemotherapy, two subgroups were defined: a standard-duration group that included patients who were treated for 180 ± 30 days and a longer duration group that included patients who received treatment for >210 days. RESULTS: The median duration of S-1 chemotherapy was 167 days, with a mean ± standard deviation of 200 ± 193 days. After excluding patients who had a recurrence within 210 days after the initiation of adjuvant chemotherapy, postoperative recurrence-free survival (RFS) and overall survival (OS) in the standard-duration group (n = 1473) and the longer duration group (n = 975) were compared. RFS and OS did not differ significantly between the standard-duration and longer duration groups (5-year RFS: 37.8% vs. 36.2% respectively; p = .6186; 5-year OS: 52.8% vs. 53.4%, respectively; p = .5850). The insignificant difference was verified by multivariate analysis and propensity-score matching analysis. CONCLUSIONS: The current findings suggest that extending S-1 adjuvant chemotherapy beyond 6 months has no significant additional effect on survival in patients with PDAC. This could be useful in determining whether to extend S-1 chemotherapy in patients who have completed the standard 6-month treatment.