Tumour formation within intestinal segments transposed to the urinary tract

Abstract

Patients and their urologists are quite rightly concerned about the possibility of neoplastic change within intestinal segments transposed to the lower urinary tract. This fear arises from the occurrence of latent adenocarcinoma arising from the urocolic anastomosis in approximately 10% of patients who underwent ureterosigmoidostomy in childhood. The present text provides an update of previous reviews and details work published since 1990 on epidemiological, experimental and clinical studies. Consideration of the collected evidence confirms the increased risk of colonic neoplasia following mixing of the faecal and urinary stream by ureterosigmoidostomy or its more recent variants. In contrast, the occurrence of tumours within transposed intestinal segments appears more likely to be related to the underlying urinary tract disease for which the surgery was performed rather than exposure of the intestinal mucosa to urine. This conclusion is, however, based on low level evidence and, despite the reassuring findings, caution is advised until more robust data are available to provide a confident risk assessment.

Colonic adenocarcinoma in an Indiana pouch successfully treated by endoscopic mucosal resection

“…8 There are two possible causes of carcinogenesis in ureterosigmoidstomy. 8 One is the mixing of the fecal and urinary stream, which results in excessive production of nitrosamines, known carcinogens, by action of colonic bacteria on urinary nitrate. The other is an inflammatory response at the site of urocolonic anastomosis, which results in reactive oxygen species and nuclear instability.…”

Current Trends in Urinary Diversion in Men

“…A thorough evaluation of the colon by a contrast enema, sigmoidoscopy, or colonoscopy is recommended when planning to use large bowel segments for the urinary diversions to rule out colonic pathology such as diverticulosis, inflammatory bowel disease, or occult colon cancer, which would prevent their use. A family or personal history of colon cancer or familial polyposis may predispose the patient to developing an adenocarcinoma in a colonic urinary reservoir segment and should be taken into consideration during the diversion selection process [28,29]. In conclusion the goal of patient counseling about urinary diversion should be to determine the method that is the safest for cancer control, that has the fewest complications over both the short and the long term and that provides the easiest adjustment for patients' lifestyle, thereby supporting the best quality of life [7].…”

Late malignant change in an ileal conduit

“…Relative increased risks have been quoted from between eight and 7000 times greater than the general population with adenocarcinoma accounting for 50-70% of the tumors, the remainder being adenomas and other benign lesions. 5 However, the uncontrolled design of these studies, the relatively small numbers of procedures being carried out, and the variety of origin of bowel segments used , are further complicated by the indication for surgery which may itself carry an increased risk of malignancy. Estimates of risk are therefore misleading and it may be better to simply conclude that there is indeed an increased risk.…”