First-line chemotherapy with S-1 alone or S-1 plus cisplatin for elderly patients with advanced gastric cancer: a multicenter propensity score matched study

Background: Fluoropyrimidine and platinum combination is the standard treatment for advanced or recurrent gastric cancer (AGC). However, fluoropyrimidine monotherapy is commonly used for elderly patients with AGC because of its good tolerability. Methods: In this multicenter retrospective study, we collected clinical data of AGC patients aged 70 years or older, treated with S-1 alone or S-1 plus cisplatin (SP) as the first-line treatment between January 2009 and December 2011. Propensity score matched cohorts (PSMC) were used for reducing the confounding effects to compare efficacy and safety between the two treatment groups. Cox regression analysis was performed to clarify the prognostic factors. Results: PSMC (n = 109 in each group) were selected from among 444 eligible patients (S-1 group, 210; SP group, 234); the S-1 group included more patients deemed unfit for intensive chemotherapy than the SP group (e.g., higher age, poorer PS, poor renal function). In the PSMC, patients’ characteristics were comparable between groups, except the male ratio (S-1 group, 64.2%; SP group, 77.1%; p = 0.04). No significant differences were observed in either overall survival [hazard ratio (HR) 0.93, p = 0.63] or progression-free survival (HR 1.09, p = 0.61). Severe adverse events (AEs) and hospitalization due to AEs were more frequent in the SP group than in the S-1 group (p < 0.001 each). Conclusion: Our findings do not support the survival benefit of SP over S-1 in elderly patients with AGC. We are now conducting a prospective comparative study to optimize treatment strategy and explore applicability of the geriatric assessment for these patients.