A phase 2 trial of intravenous and intraperitoneal paclitaxel combined with S-1 for treatment of gastric cancer with macroscopic peritoneal metastasis

BACKGROUND The prognosis of patients with gastric cancer with peritoneal metastasis is extremely poor. This phase 2 study evaluated the benefits and tolerability of weekly intravenous and intraperitoneal paclitaxel (PTX) treatment combined with oral S-1 in patients with gastric cancer who had macroscopic peritoneal metastasis. METHODS Patients with gastric cancer who had primary tumors with macroscopic peritoneal metastasis were enrolled. PTX was administered intravenously at 50 mg/m(2) and intraperitoneally at 20 mg/m(2) on days 1 and 8, respectively. S-1 was administered at 80 mg/m(2) per day for 14 consecutive days, followed by 7 days of rest. The primary endpoint was the 1-year overall survival (OS) rate. The secondary endpoints were the response rate, efficacy against malignant ascites, and safety. RESULTS Thirty-five patients were enrolled. The median number of treatment courses was 11 (range, 2-35). The 1-year OS rate was 77.1% (95% confidence interval, 60.5-88.1). The overall response rate was 71% in 7 patients with target lesions. Malignant ascites disappeared or decreased in 15 of 22 (68%) patients. The frequent grade 3/4 toxic effects were neutropenia (34%), leukopenia (23%), and anemia (9%). CONCLUSIONS Combination chemotherapy consisting of intravenous and intraperitoneal PTX with S-1 is well-tolerated and effective in patients with gastric cancer who have macroscopic peritoneal metastasis. Cancer 2013;119:3354-8. (c) 2013 American Cancer Society.