Long-term outcomes and prognostic factors of patients with advanced gastric cancer treated with S-1 plus cisplatin combination chemotherapy as a first-line treatment

The long-term outcomes of advanced gastric cancer (AGC) patients treated with S-1 plus cisplatin (SP) combination chemotherapy remain unclear. Therefore, we sought to evaluate these outcomes to identify the prognostic factors affecting patient survival. We retrospectively analyzed 153 AGC patients treated with SP at a single institution between January 2005 and July 2011. Median overall survival (OS) was 15.0 months [95 % confidence interval (CI), 12.5-17.9 months]. Three independent prognostic factors affecting poor survival were identified: performance status (PS) a parts per thousand yen 1 [hazard ratio (HR) = 2.39, 95 % CI, 1.58-3.62); > 1 metastatic site (HR = 1.57, 95 % CI, 1.10-2.26], and elevated alkaline phosphatase levels (HR = 1.70, 95 % CI, 1.16-2.49). A simple prognostic index was generated using three risk groups: good (no risk factor), moderate (one or two risk factors), and poor (three risk factors). The median OS for good-, moderate-, and poor-risk groups was 28.6, 14.8, and 7.3 months, respectively (log-rank test; P < 0.0001). Among the twelve 3-year survivors, 9 (75 %) had a PS of 0 and 8 (67 %) had only one metastatic site. Three prognostic factors were identified in AGC patients treated with SP. Using a simple prognostic index, the patients were divided into three risk groups, in which the survival differences were markedly significant, suggesting that patients with good PS and only one metastatic site may have a higher chance of long-term survival than those with poor PS and multiple metastatic sites.