et al. – Creatinine clearance (CCr) <60 ml/min was a significant risk factor for 6–month continuation of S–1 adjuvant chemotherapy, even though the renal function was judged as normal by the serum creatinine level. Careful attention is therefore required for S–1 continuation in patients with CCr <60 ml/min.

• The study selected patients who underwent curative D2 surgery for gastric cancer, were diagnosed with stage 2 or 3 disease, had a serum creatinine level of ≤1.2 mg/dl, and received adjuvant S-1 between June 2002 and March 2011.

• One hundred of these patients were eligible for the present study.
• A comparison of 6-month continuation of S-1 stratified by various clinical factors, using the log-rank test, revealed a marginally significant difference in creatinine clearance (CCr) between those patients who continued for 6 months and those who did not.
• A CCr of 60 ml/min was regarded as the critical point.
• Uni- and multivariate Cox’s proportional hazard analyses demonstrated that CCr was the only significant independent factor for the prediction of 6-month continuation.
• The 6-month continuation rate was 72.9 % in the patients with CCr ≥60 ml/min, and 40.0 % in patients with CCr <60 ml/min (P = 0.015).
• Adverse events occurred more frequently and earlier in the patients with CCr <60 ml/min than in those with CCr ≥60 ml/min.