Biological effects of short course radiation in transitional cell carcinoma of the bladder

We evaluated the biologic effects of short course radiation therapy (1800 to 2000 rads) administered before cystectomy by placing tumors in tissue culture and observing their growth. No differences in growth were observed between irradiated and nonirradiated tumors. The minimal sublethal dose of radiation that effectively suppresses the growth of transitional cell carcinoma needs to be determined.