Induction of carcinoma at ureterosigmoid anastomosis--with and without faecal stream

Histological and histochemical changes of the intestinal mucosa at the urothelial-enteric anastomotic site

OBJECTIVE

The incorporation of bowel segments for urinary tract reconstruction may induce intestinal mucosal changes with the development of metabolic, nutritional, gastrointestinal and carcinogenic complications. The early histological and histochemical changes of the intestinal mucosa in contact with the feces-urine mixture, are evaluated in the present study.

MATERIALS AND METHODS

Twelve rats (operated group) were submitted to a vesico-colonic anastomosis, and 10 rats (control group) underwent a sham operation (the colon was opened and immediately sutured). On the operated group, the left colon was divided into 3 equal portions and the middle segment was used for the bladder-colonic anastomosis. After 20 weeks, the animals were sacrificed and the entire left colon in each group, as well as the bladder and the vesico-colonic anastomosis in the operated group, was removed. The proximal, middle (anastomotic site in the operated group and sutured portion in the control group) and distal colon were used for histological and histochemical studies.

RESULTS

Metaplasia, chronic inflammatory process and fibrosis were significantly greater at the anastomotic site compared to the middle segment of the control group. There were no differences in both groups in terms of dysplasia, atrophy and hypertrophy either on the proximal, middle or anastomotic area and distal portion of the left colon. All animals in the operated group showed a reduced presence of sulfomucin and an increase in the sialomucin content.

CONCLUSION

The histological changes observed in this study may suggest a precancerous phenomenon.

SECONDARY MALIGNANCIES IN DIFFERENT FORMS OF URINARY DIVERSION USING ISOLATED GUT

PURPOSE

Tumor development following ureterosigmoidostomy is a worldwide accepted late complication. In contrast, tumor risk in other forms of urinary diversion with the separation of urine and feces is still unclear. We present a complete and detailed analysis of all reported tumors following urinary diversions using isolated gut segments in the literature. We estimated the tumor risk in comparison to ureterosigmoidostomies and to the general population.

MATERIALS AND METHODS

We reviewed the world literature up to April 2003 via MEDLINE for secondary tumors in urinary diversions using isolated intestinal segments.

RESULTS

We found 81 tumor case reports following urinary diversion using isolated intestinal segments. Tumors developed in 18 conduits, 45 cystoplasties, 5 rectal bladders, 3 neobladders, 6 colonic pouches and 4 ileal ureter replacements.

CONCLUSIONS

All urinary diversions using bowel with or without separation of urine and feces carry a significantly higher tumor risk for intestinal tumor development compared to the general population. The tumor spectrum and tumor location in isolated gut segments are different than tumors following ureterosigmoidostomies but the total tumor risk is probably similar. The latency period depends on the initial diagnosis with malignant diseases leading to a shorter induction time. Concerning etiology, many theories exist but the exact mechanism remains unclear. Regular endoscopic control beginning with postoperative year 3 for early detection of secondary malignancies is mandatory.

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 vesicosigmoidostomy with proximal colostomy was performed, in group 2, vesicosigmoidostomy. The total tumor incidence did not 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 hundred and ten other Wistar rats were randomized into three groups. Animals in group A received vesicoileosigmoidostomy, group B, two-step vesicosigmoidostomy with initial separation of urine and the urocolonic anastomosis, group C, vesicosigmoidostomy. Significantly fewer adenocarcinomas 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 indicate a similar cancer risk in all continent forms of urinary diversion, at least via colon. Ileal interposition seems to be an effective carcinoma prophylaxis following ureterosigmoidostomy. The proliferative instability at the urointestinal anastomosis is crucial for the pathogenesis and prophylaxis of this form of carcinogenesis, whereas urine seems to play only a minor role.