[Effect of post operative maintenance chemotherapy against ovarian cancer]

The significance of maintenance chemotherapy after surgery for ovarian cancer was examined using a human tumor-nude mouse system. Experiment 1: The human yolk sac tumor of the ovary (YST-2) heterotransplanted into nude mice was used. The tumor-bearing mice were administered 100 mg/kg of 1-Hexylcarbamoyl-5-fluorouracil (HCFU) orally for 60 days after tumor resection. Control mice were given 0.1 ml 0.3% methylcellulose after tumor resection. When the tumor was completely resected by surgery, HCFU treatment succeeded in decreasing the recurrence rate of the tumor, and in improving the survival rate of the host mice. However, when the macroscopic tumor was left in the host mouse, HCFU treatment did not affect either the recurrence rate of the tumor or the survival rate. Experiment 2: The human poorly differentiated adenocarcinoma of the ovary (OVA-2) heterotransplanted into nude mice was used. Administration of 100 mg/kg of HCFU immediately after the heterotransplantation into nude mice for 60 days suppressed the tumor growth. HCFU treatment improved the survival rate of the tumor-bearing mice. The antitumor effect of HCFU on the OVA-2 tumor was confirmed by histological examination. These experiments revealed that the maintenance chemotherapy after surgery for ovarian cancer was important in the effective treatment of the patient (tumor-bearing host).