SQUAMOUS-CELL CARCINOMA GROWTH IN IRRADIATED TISSUE - A MURINE MODEL FOR QUANTITATIVE ASSESSMENT OF TREATMENT

Locoregional recurrent and distant metastases from squamous cell carci nomas, despite multimodality therapy, remain troublesome clinical real ities, Discrepancies in success rates of various surgery and radiation treatment regimens dealing with these problems are confusing to the c linician attempting to recommend the most beneficial treatments. There is a need for an experimental model to assess therapeutic effectivene ss quantitatively from which guidelines for developing clinical trials may be suggested. In this study, we provide such a model. We injected DBA-2 mice with defined numbers of KLN-205 squamous carcinoma cells t o obtain baseline growth characteristics; 216 animals had no previous irradiation, The remaining 131 received 30 Gy irradiation to the right leg 50 days before injection of the tumor cells, Tumor incidence, gro wth and number, and location of tumor metastasis were determined in bo th previously irradiated and nonirradiated groups, The data demonstrat e a growth-retardant effect on tumor groups by the previous irradiatio n (tumor bed effect), The data also show that the incidence of hematog enously spread metastases was more frequent in mice in which tumors de veloped in previously irradiated tissue than in mice with tumors in no nirradiated tissue.