title: Risk factors for discontinuation of s-1 adjuvant chemotherapy for gastric cancer.
abstract: OBJECTIVE
  The aim of this study was to clarify the risk factors for discontinuing tegafur/gimeracil/oteracil potassium (S-1) adjuvant chemotherapy following gastrectomy in patients with gastric cancer.
  
  
  METHODS
  We retrospectively investigated patients with curatively-resected gastric cancer who received S-1 adjuvant chemotherapy. S-1 was administered orally at 80-120 mg/day, depending on body surface area, on days 1-28 every 6 weeks for 1 year. The dose and treatment schedule were modified at the clinicians' discretion, according to toxicity.
  
  
  RESULTS
  Seventy-one patients were included in the study, 26 of whom discontinued S-1 therapy. The relapse-free survival rates in the S-1-completed and S-1-discontinuation groups at 5 years post-surgery were 88.1% and 55.8%, respectively. The overall survival rates in the S-1-completed and S-1-discontinuation groups at 5 years post-surgery were 89.4% and 59.8%, respectively. The hazard ratios for relapse and death were significantly lower in the S-1-completed group compared with those in the S-1-discontinuation group (0.18; p<0.001 and 0.19; p=0.002, respectively). Multivariate logistic regression analysis revealed that S-1 discontinuation was significantly associated with an initial overdose of S-1, having stage I cancer, creatinine clearance <66 mL/min, and a side effect of nausea.
  
  
  CONCLUSIONS
  These results suggest that assessing renal function to avoid initial overdose of S-1, together with the early management of side effects, may support the continuation of S-1 adjuvant chemotherapy in patients with gastric cancer.
authors: 1. Division of Pharmacy, Ehime University Hospital, Shitsukawa, Toon, Ehime 791-0295, Japan;
authors: Hitoshi
authors: H
authors: Kawazoe
authors: 2. Department of Clinical Pharmacy, College of Pharmaceutical Sciences, Matsuyama University, Bunkyou, Matsuyama, Ehime 790-8578, Japan;
authors: Maya
authors: M
authors: Shimasaki
authors: 1. Division of Pharmacy, Ehime University Hospital, Shitsukawa, Toon, Ehime 791-0295, Japan;
authors: Masaki
authors: M
authors: Ueno
authors: 1. Division of Pharmacy, Ehime University Hospital, Shitsukawa, Toon, Ehime 791-0295, Japan;
authors: Satomi
authors: S
authors: Sumikawa
authors: 2. Department of Clinical Pharmacy, College of Pharmaceutical Sciences, Matsuyama University, Bunkyou, Matsuyama, Ehime 790-8578, Japan;
authors: Shingo
authors: S
authors: Takatori
authors: 2. Department of Clinical Pharmacy, College of Pharmaceutical Sciences, Matsuyama University, Bunkyou, Matsuyama, Ehime 790-8578, Japan;
authors: Hiroyuki
authors: H
authors: Namba
authors: 3. Division of Gastrointestinal Surgery and Surgical Oncology, Department of Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan.
authors: Motohira
authors: M
authors: Yoshida
authors: 3. Division of Gastrointestinal Surgery and Surgical Oncology, Department of Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan.
authors: Koichi
authors: K
authors: Sato
authors: 3. Division of Gastrointestinal Surgery and Surgical Oncology, Department of Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan.
authors: Yoh
authors: Y
authors: Kojima
authors: 3. Division of Gastrointestinal Surgery and Surgical Oncology, Department of Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan.
authors: Yuji
authors: Y
authors: Watanabe
authors: 1. Division of Pharmacy, Ehime University Hospital, Shitsukawa, Toon, Ehime 791-0295, Japan;
authors: Toshihide
authors: T
authors: Moriguchi
authors: 1. Division of Pharmacy, Ehime University Hospital, Shitsukawa, Toon, Ehime 791-0295, Japan;
authors: Akihiro
authors: A
authors: Tanaka
authors: 1. Division of Pharmacy, Ehime University Hospital, Shitsukawa, Toon, Ehime 791-0295, Japan;
authors: Hiroaki
authors: H
authors: Araki
keywords: Adjuvant chemotherapy; Discontinuation; Gastric cancer; Risk factor.; Tegafur/gimeracil/oteracil potassium (S-1)