Background: Doses and schedules of the combination of S-1 and cisplatin for the treatment of advanced gastric cancer (AGC) have not been standardized. We therefore evaluated the efficacy and feasibility of a 3-week schedule of S-1 and cisplatin in patients with AGC, as well as assessing factors prognostic of patient outcomes.
Methods: A total of 159 patients with AGC were treated with S-1 (40 mg/m(2) bid on days 1-14) and cisplatin (60 mg/m(2) IV on day 1) between January 2004 and December 2008.
Results: Median follow-up duration was 20.0 months (range, 11.4-48.5 months), during which time 129 patients (81.1%) died. Patients received a median 6 cycles of chemotherapy (range, 1-19 cycles). Among the 59 patients with measurable disease, 1 achieved a complete response (1.7%) and 24 (40.7%) had partial responses, giving an overall response rate of 42.4% (95% CI, 23.0-61.8%). The median progression-free survival (PFS) was 5.8 months (95% CI, 4.8-6.9 months), and the median overall survival (OS) was 11.3 months (95% CI, 9.6-13.0 months). Multivariate analysis showed that initial metastasis, bone metastasis, and liver metastasis were independent prognostic factors for reduced PFS, whereas poor performance status, initial metastasis, and bone metastasis were prognostic for reduced OS. Application of a previous prognostic model showed that observed PFS and OS survival curves for patients in various risk groups differed significantly (P < 0.001 each).
Conclusions: A 3-week regimen of S-1 plus cisplatin was active and well tolerated as first-line treatment in patients with AGC. Disease status and bone metastasis were the most important prognostic factors.