Urothelial susceptibility to tumor cell implantation: comparison of cauterization with N-methyl-N-nitrosourea.

To determine whether or not transitional cell carcinoma cells will preferentially implant and grow on an altered urothelial surface, cauterization and instillation of N-methyl-N-nitrosourea (MNU) were used to alter the murine bladder urothelium. Transplantable tumor cells (2.09 X 10(6) ) were placed into the bladders of 53 mice. Tumor cell implantation occurred in only 6 per cent of the mice with a normal bladder, whereas tumors were present in 28 per cent of mice pretreated with intravesical MNU and in 67 per cent of mice which had a portion of the bladder cauterized prior to insertion of tumor cells (p less than 0.005). This study not only establishes the optimal technique for implantation in this experimental model, but also suggests that seeding may be a contributory factor in the high recurrence rate following endoscopic treatment of bladder tumors in man.