Phase II study of weekly intravenous and intraperitoneal paclitaxel combined with S-1 for advanced gastric cancer with peritoneal metastasis
4542 Background: A phase II study to evaluate the efficacy and tolerability of weekly intravenous and intraperitoneal paclitaxel combined with S-1 was performed in gastric cancer patients with peritoneal metastasis. Methods: Gastric cancer patients with peritoneal dissemination and/or cancer cells on peritoneal cytology were enrolled. Paclitaxel was administered intravenously at 50 mg/m2 and intraperitoneally at 20 mg/m2 on days 1 and 8. S-1 was administered at 80 mg/m2/day for 14 consecutive days, followed by 7 days rest. The primary endpoint was the 1-year overall survival rate. Secondary endpoints were the response rate, efficacy against malignant ascites and safety. Results: Forty patients were enrolled, including 21 with primary tumors with peritoneal dissemination confirmed by staging laparoscopy, 13 with peritoneal recurrence, and 6 with positive peritoneal cytology only. The median number of courses administered was 7 (range 1–23). The 1-year overall survival rate was 78% (95% CI, 65–90%). The overall response rate was 56% (95% CI, 32–79%) in 18 patients with target lesions. Malignant ascites disappeared or decreased in 13 of 21 (62%) patients. The incidences of grade 3/4 hematological and non- hematological toxicities were 40% and 15%, respectively. The frequent grade 3/4 toxicities included neutropenia (38%), leukopenia (18%), anemia (10%), and nausea (8%). Catheter obstruction observed in one patient was the only complication related to the peritoneal access device or intraperitoneal infusion. There were no treatment-related deaths. Conclusions: Combination chemotherapy of intravenous and intraperitoneal paclitaxel with S-1 is well tolerated and active in gastric cancer patients with peritoneal metastasis. No significant financial relationships to disclose.