Intraperitoneal chemotherapy for gastric cancer with peritoneal metastasis

Peritoneal metastasis is the most frequent pattern of gastric cancer recurrence or metastasis and is a definitive determinant of prognosis. However, an effective means of treating peritoneal disease has not yet been established. Systemic chemotherapy has only a limited effect on peritoneal metastasis, although some progress has been shown in terms of median survival time, especially among patients with a minimal or moderate disease burden. Clinical research related to intraperitoneal administration of anticancer drugs is currently underway. An advantage of intraperitoneal chemotherapy is the ability to achieve high concentrations of anticancer drugs in the peritoneal cavity and the direct exposure of peritoneal deposits and free cancer cells to those drugs. In addition, pharmacokinetic studies with taxanes have shown that these high intraperitoneal drug concentrations are sustained for a considerable length of time, allowing prolonged exposure. As taxanes are the most appropriate drugs for intraperitoneal administration, the development of repeated intraperitoneal chemotherapy using taxanes for gastric cancer peritoneal metastasis-either alone or in combination with systemic chemotherapy-has taken place over the past decade, mostly in Japan. Several phase II trials and a phase III trial have recently demonstrated the efficacy of this therapy, including median survival times of 14.4-24.6 months and one-year overall survival rates of 67-91%. These results may lead to the approval of intraperitoneal taxanes, especially paclitaxel, for official insurance coverage in the near future.