Background: Compliance of S-1 adjuvant chemotherapy is not high. The aim of the present study is to clarify risk factors for continuation of S-1 after gastrectomy.
Methods: This retrospective study selected patients who underwent curative D2 surgery for gastric cancer, were diagnosed with stage 2/3 disease, creatinine clearance more than 60 ml/min, and received adjuvant S-1 at our institution between June of 2002 and December of 2011. Time to S-1 treatment failure (TTF) was calculated.
Results: A total of 103 patients were selected for the present study. When TTF curve stratified by each clinical factor was compared by the log-rank test, body weight loss (BWL) of 15 % was regarded as a critical point. Both univariate and multivariate Cox proportional hazard analyses demonstrated that BWL was the significant independent risk factor. Moreover, BWL remained a significant factor in both the univariate and multivariate analyses in the subset excluding 8 patients who discontinued S-1 because of recurrence. The 6-month continuation rate was 66.4 % in the patients with BWL < 15 and 36.4 % in patients with BWL ≥ 15 % (P = .017).
Conclusions: BWL was the most important risk factor for the compliance of adjuvant chemotherapy with S-1 in the patients with stage 2/3 gastric cancer who underwent D2 gastrectomy. To improve drug compliance that leads to survival, it is a key to maintain body weight before starting S-1 adjuvant. Our study emphasizes the requirement for adequate studies of perioperative nutritional intervention in patients who receive gastrectomy for advanced gastric cancer.