Experimental postoperative adjuvant chemotherapy by UFT using primary tumor amputation model

We evaluated the postoperative adjuvant chemotherapy by UFT using the prima ry tumor amputation-pulmonary metastasis model. When Lewis lung carcinoma ( LLC) primary tumors on the hind foot pad grew palpable, they were amputated on two different days. In experiment (A) (earlier amputation model), micro metastases were detected on the day of amputation only by the histopatholog ical examination. In the experiment (B) (later amputation model), nodules c ould be determined even by necropsy. Long-term (60-day) consecutive adminis tration of UFT (22 mg/kg/day), which produced no body weight loss, markedly prolonged the survival period in experiment (A) (ILS: over 118%), 1 of the 15 mice being cured. UFT had a relatively weak but significant effect (67% of ILS) in schedule (B). Using the same model, we examined the inhibitory effect of UFT (2-week administration) on the number of metastatic nodules. A significant decrease of metastatic nodules was observed by UFT with both amputation schedules, but its effect was superior with schedule (A). In the same model using Colon 26 PMF-15, UFT markedly prolonged the survival peri od of mice (150% of ILS) and significantly decreased the metastatic nodules (86% inhibition). The dose of UFT used was relatively low, and did not sig nificantly inhibit the growth of large tumors. However, the sensitivity to the micrometastases was high. These findings suggest that the post-operativ e adjuvant chemotherapy by the long-term consecutive administration of UFT would be effective for clinical cancer especially in curatively resected ca ses.