[The updated treatment strategy for gastric cancer with peritoneal metastasis]

The standard of care for gastric cancer with peritoneal metastasis is chemotherapy. However, there is no chemotherapy regimen with a sufficient level of evidence, and thus S-1 plus cisplatin (CDDP), which is regarded as the standard regimen for advanced metastatic gastric cancer, is widely applied. Meanwhile the efficacy of intraperitoneal (IP) administration of taxanes has been verified, and the novel multidisciplinary treatment combining chemotherapy and surgery is now being tested. We developed a combination chemotherapy regimen of S-1, weekly intravenous and IP paclitaxel (PTX), and determined the recommended dose of IP PTX to be 20 mg/m2 in our phase I study. In our phase II study, the median survival time (MST) of 40 patients enrolled was 23.6 months, and peritoneal cytology turned negative for 86% of 28 patients. Moreover, we performed gastrectomy on 52 patients after disappearance or obvious shrinkage of peritoneal metastasis, and the MST was 34.9 months. The multidisciplinary treatment combining IP-containing chemotherapy and surgery is safe and effective for gastric cancer patients with peritoneal metastasis. We have just started a phase III trial (PHOENIX-GC trial) comparing our IP regimen versus S-1 plus CDDP.