TUMOR-INDUCTION AND PROPHYLAXIS FOLLOWING DIFFERENT FORMS OF INTESTINAL URINARY-DIVERSION IN A RAT MODEL

Eighty Wistar rats were randomized into two groups. In group 1 vesicos igmoidostomy with proximal colostomy was performed, in group 2, vesico sigmoidostomy. The total tumor incidence did not differ significantly group 1 10/40, 25%; group 2 13/40, 32.5%). The tumor spectrum differed , with more adenocarcinomas in group 2 (11/40, 27.5% vs 4/40, 10%; P = 0.047) and urothelial carcinomas only in group 1 (5/40, 2.5%). One hu ndred and ten other Wistar rats were randomized into three groups. Ani mals in group A received vesico-ileosigmoidostomy, group B, two-step v esicosigmoidostomy with initial separation of urine and the urocolonic anastomosis, group C, vesicosigmoidostomy. Significantly fewer adenoc arcinomas were observed in group A (2/40, 5%) than in group B (16/40, 40%; P < 0.002) and group C (9/30, 30%; P < 0.007). These results indi cate a similar cancer risk in all continent forms of urinary diversion , at least via colon. Ileal interposition seems to be an effective car cinoma prophylaxis following ureterosigmoidostomy. The proliferative i nstability at the urointestinal anastomosis is crucial for the pathoge nesis and prophylaxis of this form of carcinogenesis, whereas urine se ems to play only a minor role.