[A case of advanced gastric cancer with peritoneal dissemination effectively treated with fourth-line chemotherapy of S-1 alone].

The patient was a 42-year-old female diagnosed with unresectable highly advanced gastric cancer complicated by peritoneal dissemination. We performed systemic chemotherapy with MTX+5-FU as the first-line treatment, which stabilized the disease. Since the patient initially wished a radical resection, we tried chemotherapy with weekly PTX as a second-line treatment. Her therapeutic response remained between a partial response and a stable disease for about five months, followed, however, by progressive disease. The result of the third-line treatment with CPT-11+CDDP was again a progressive disease, so we switched her regimen to single-agent S-1 as a fourth-line treatment. The ascites disappeared three months after the change in regimen. As of March 2006, the patient had survived for 17 months since diagnosis (8 months since the ongoing S-1 therapy started) and the disease is currently stabilized, and preserving a favorable performance status. However, in June 2006, the patient died of pneumonia 20 months after the diagnosis.