Three-weekly S-1 plus cisplatin chemotherapy as first-line treatment for advanced gastric cancer

Combination chemotherapy of S-1 and cisplatin has shown promising activity against advanced gastric cancer, but the schedules and dose intensities of S-1 and cisplatin have not been consistent in several clinical trials. We investigated the efficacy and toxicity of 3-weekly S-1/cisplatin chemotherapy as first-line treatment in metastatic or relapsed gastric cancer (MRGC). Forty-six patients with MRGC were prospectively enrolled. S-1 (80 mg/m²/day; days 1–14) and cisplatin (60 mg/m²; day 1) were administrated every 3 weeks. Among 46 patients who received chemotherapy, one achieved a complete response and 21 achieved a partial response, resulting in an overall response rate (RR) of 48%. Thirteen patients (28%) had stable disease and eight patients (17%) had progressive disease. After a median follow-up duration of 48.3 weeks, the median progression-free survival (PFS) and overall survival (OS) were 21.1 weeks and 68.3 weeks, respectively. Patients with good Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0–1 had prolonged PFS and OS compared with patients with ECOG PS of 2. Common hematologic toxicities were anemia (93%), leucopenia (61%), and neutropenia (61%). However, grade 3/4 anemia, leucopenia, and neutropenia developed in only 11, 9, and 24% of patients, respectively. Grade 3/4 non-hematologic toxicities included anorexia (22%), fatigue (13%), nausea (7%), and diarrhea (7%). No treatment-related mortality occurred. Three-weekly S-1/cisplatin chemotherapy was active and well-tolerated in MRGC patients.