[A case of effective treatment with chemosensitivity test-guided chemotherapy for advanced pancreatic and gastric cancer with peritoneal metastasis].

: A 63-year-old man with abdominal pain was diagnosed as locally advanced pancreatic tail cancer and gastric cancer with peritoneal metastasis based on computed tomography (CT) and gastrointestinal series. Preoperative serum CA19- 9 was 1,357 U/mL. During laparotomy, peritoneal dissemination was observed and confirmed pathologically. An ileoileostomy was performed and peritoneal tissue was submitted to a chemosensitivity test. Based on the chemosensitivity test, CPT-11 (50 mg/body), 5-FU (750 mg/body), and Leucovorin (375 mg/body) were administered intravenously once a week for 3 weeks with a 1-week rest as 1 course. The patient received 9 courses of chemotherapy until progressive disease. Stable disease in tumor size was observed and serum CA19-9 level dropped to 81 U/mL. He remained well without any symptoms and pursued normal activity for 15 months. He died of peritoneal dissemination 26 months after diagnosis. Chemosensitivity test-guided chemotherapy seems to be an effective regimen as individualized chemotherapy for advanced pancreatic and gastric cancer.