title: Feasibility of oral administration of S-1 as adjuvant chemotherapy in gastric cancer: 4-week S-1 administration followed by 2-week rest vs. 2-week administration followed by 1-week rest.
abstract: In 2006, the Adjuvant Chemotherapy Trial of S-1 for Gastric Cancer (ACTS-GC) demonstrated that S-1 is an effective adjuvant therapy for gastric cancer. Following that study, S-1 has been used as the standard adjuvant therapy for gastric cancer in Japan. However, the 1-year completion rate was only 65.8% in the ACTS-GC study and feasibility remains a critical issue. We conducted a study to evaluate the feasibility of 2 weekly administration regimens of S-1 as adjuvant chemotherapy in gastric cancer. The criteria for eligibility included histologically proven stage II (excluding T1), IIIA or IIIB gastric cancer with D2 lymph-node dissection. The patients were randomly assigned to either arm A (S-1 administration for 4 weeks followed by 2 weeks of rest) or arm B (S-1 administration for 2 weeks followed by 1 week of rest). In each arm, treatment was continued for 12 months unless recurrence or severe adverse events were observed. The primary endpoint was feasibility (protocol treatment completion rate). The secondary endpoints were safety, relapse-free survival and overall survival. A total of 47 patients were assigned to arms A or B between May, 2008 and February, 2010. During the first interim analysis, the protocol treatment completion rates in arms A and B were 83 and 100%, respectively at 6 months and 49 and 89%, respectively, at 12 months (P=0.0046). Therefore, S-1 administration for 2 weeks followed by 1 week rest was more feasible as adjuvant chemotherapy in gastric cancer. Grade 3 adverse events in arm A included fatigue (8.0%), anorexia (8.0%), nausea (4.0%), vomiting (4.0%) and hand-foot syndrome (4.0%), whereas none were observed in arm B. There were no reported grade 4 adverse events in either arm. In conclusion, the 2-week S-1 administration followed by 1-week rest regimen appears to be a more feasible oral administration regimen for S-1 as adjuvant chemotherapy in gastric cancer.
authors.affiliation: Department of General Surgery, Kawasaki Medical School, Okayama, Okayama 700-8505, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Yamatsuji
authors.affiliation: Department of Surgery, Hiroshima City Hospital, Hiroshima, Hiroshima 730-8518, Japan ; Department of Gastroenterological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Okayama 700-8558, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Fujiwara
authors.affiliation: Department of Digestive Surgery, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Matsumoto
authors.affiliation: Department of Surgery, Shikoku Cancer Center, National Hospital Organization, Matsuyama, Ehime 791-0280, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Hato
authors.affiliation: Department of Surgery, Kochi University Medical School, Kochi, Kochi 783-8505, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Namikawa
authors.affiliation: Department of Surgery, Kochi University Medical School, Kochi, Kochi 783-8505, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hanazaki
authors.affiliation: Department of General Surgery, Kawasaki Medical School, Okayama, Okayama 700-8505, Japan.
authors.forename: Munenori
authors.initials: M
authors.lastname: Takaoka
authors.affiliation: Department of General Surgery, Kawasaki Medical School, Okayama, Okayama 700-8505, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Hayashi
authors.affiliation: Department of General Surgery, Kawasaki Medical School, Okayama, Okayama 700-8505, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Shigemitsu
authors.affiliation: Department of General Surgery, Kawasaki Medical School, Okayama, Okayama 700-8505, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Department of General Surgery, Kawasaki Medical School, Okayama, Okayama 700-8505, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Urakami
authors.affiliation: Department of Gastroenterological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Okayama 700-8558, Japan.
authors.forename: Futoshi
authors.initials: F
authors.lastname: Uno
authors.affiliation: Department of Gastroenterological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Okayama 700-8558, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Nishizaki
authors.affiliation: Department of Gastroenterological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Okayama 700-8558, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Kagawa
authors.affiliation: Department of Surgery, Hiroshima City Hospital, Hiroshima, Hiroshima 730-8518, Japan.
authors.forename: Motoki
authors.initials: M
authors.lastname: Ninomiya
authors.affiliation: Department of Gastroenterological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Okayama 700-8558, Japan.
authors.forename: Toshiyoshi
authors.initials: T
authors.lastname: Fujiwara
authors.affiliation: Department of Digestive Surgery, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Hirai
authors.affiliation: Department of Digestive Surgery, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Department of General Surgery, Kawasaki Medical School, Okayama, Okayama 700-8505, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Haisa
authors.affiliation: Department of General Surgery, Kawasaki Medical School, Okayama, Okayama 700-8505, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Naomoto
keywords: S-1; adjuvant chemotherapy; feasibility; gastric cancer; randomized controlled trial