Surgical adjuvant chemotherapy of metastatic murine osteosarcoma.

A C3H murine osteosarcoma was used to investigate the effects of surgical adjuvant chemotherapy and to establish the relationship between primary tumor size and the number of metastatic lung tumor foci. The transplanted primary tumor was allowed to grow for 28 or 33 days and the lungs were monitored for microscopic colonies. Animals whose tumors were left in situ had 6-124 and 32-338 colonies in the lungs at 28 and 33 days, respectively. When the primary tumor was excised on day 10 post implantation, metastatic tumor colonies on day 33 were reduced to 0-24 colonies. The results indicated that the longer the primary tumor was left in the host the greater was the number of tumor cells which seeded to the lungs. Early surgical (day 10) removal of the tumor gave better survival than late (day 20) surgical removal of the tumor. When cyclophosphamide chemotherapy was used with surgery, better survival (80%) was seen. Cyclophosphamide alone did not improve survival over that seen for tumor-bearing controls. Late surgery with adjuvant chemotherapy increased survival time.