BACKGROUND: Adjuvant chemotherapy with S-1 was proven to be effective in Japanese patients with advanced gastric cancer curatively resected with D2 lymph node dissection. MATERIALS AND METHODS: We retrospectively evaluated the medical records of 305 patients with stage II, III or IV (M0) gastric cancer who had received adjuvant S-1 chemotherapy following curative gastrectomy with D2 lymph node dissection between October 2007 and December 2009. Adjuvant S-1 was administered at a dose of 40 mg/m(2) twice daily for 4 weeks followed by 2 weeks of rest, every 6 weeks for eight cycles. RESULTS: Of the 305 patients, 248 (81.3 %) and 198 (64.9 %) completed four and eight cycles of adjuvant chemotherapy, respectively. The most common reasons for discontinuing treatment prior to the planned eight cycles were adverse events (n = 47, 15.4 %) and tumor recurrence (n = 28, 9.2 %). Sixty-five (21.3 %) patients required dose reduction due to adverse events. The most common grade 3/4 toxicities were neutropenia (n = 39, 12.8 %), diarrhea (n = 15, 4.9 %). Multivariate analysis showed that total gastrectomy [odds ratio (OR) 2.44; 95 % confidence interval (CI) 1.29-4.62, p = 0.006] was an independent risk factor for grade 3/4 hematologic toxicities, and age > 65 years (OR 2.60; 95 % CI 1.34-5.07, p = 0.005) was an independent risk factor for grade 3 non-hematologic toxicities. CONCLUSIONS: Adjuvant chemotherapy with S-1 for 1 year is safe and feasible in Korean patients. Age > 65 years and total gastrectomy are independent risk factors for severe adverse events caused by adjuvant S-1 chemotherapy.
BACKGROUND: Adjuvant chemotherapy with S-1 was proven to be effective in Japanese patients with advanced gastric cancer curatively resected with D2 lymph node dissection. MATERIALS AND METHODS: We retrospectively evaluated the medical records of 305 patients with stage II, III or IV (M0) gastric cancer who had received adjuvant S-1 chemotherapy following curative gastrectomy with D2 lymph node dissection between October 2007 and December 2009. Adjuvant S-1 was administered at a dose of 40 mg/m(2) twice daily for 4 weeks followed by 2 weeks of rest, every 6 weeks for eight cycles. RESULTS: Of the 305 patients, 248 (81.3 %) and 198 (64.9 %) completed four and eight cycles of adjuvant chemotherapy, respectively. The most common reasons for discontinuing treatment prior to the planned eight cycles were adverse events (n = 47, 15.4 %) and tumor recurrence (n = 28, 9.2 %). Sixty-five (21.3 %) patients required dose reduction due to adverse events. The most common grade 3/4 toxicities were neutropenia (n = 39, 12.8 %), diarrhea (n = 15, 4.9 %). Multivariate analysis showed that total gastrectomy [odds ratio (OR) 2.44; 95 % confidence interval (CI) 1.29-4.62, p = 0.006] was an independent risk factor for grade 3/4 hematologic toxicities, and age > 65 years (OR 2.60; 95 % CI 1.34-5.07, p = 0.005) was an independent risk factor for grade 3 non-hematologic toxicities. CONCLUSIONS: Adjuvant chemotherapy with S-1 for 1 year is safe and feasible in Korean patients. Age > 65 years and total gastrectomy are independent risk factors for severe adverse events caused by adjuvant S-1 chemotherapy.