The carcinogenic activity of nitrosamines was recognized as early as 1956 ( I ) . More recently attention has been focused on the nitrosamines as environmental carcinogens (2, 3). Their presence appears to be ubiquitous ( 4 ) ; however, nitrosamines are very difficult to detect at low concentrations and a group analysis is of limited value for not all nitrosamines are carcinogenic. Automatic colorimetric analysis (5), pyrolysis after GC separation (6), formation of electron capturing derivatives by reaction with fluorinated anhydrides and pyridine (7), mass spectrometry (8), gas chromatography (9j and combined GC/MS (10) are some of the methods that have been applied to the analysis of Nnitroso compounds.

We followed postoperatively 75 patients who underwent ureterosigmoidostomy between 1942 and 1987. Of the patients 30 were asked to undergo routine examination, including fiberoptic sigmoidoscopy with biopsy and analysis of a urine-feces slurry for nitrate, nitrite and nitrosamines in comparison to 20 control volunteers. After a mean observation of 14 years 7 months (1 to 46 years) 64.5% of the patients had bilaterally normal kidneys without any previous complications, 77.5% of the renal units being normal. Sigmoidoscopic biopsy revealed 3 carcinomas at the ureterocolonic junction resulting in an 8.5 to 10.5-fold increased risk of colon carcinoma compared to the general population. The excretion of nitrite and N-nitrosamines was increased, and nitrate excretion was decreased compared to healthy control volunteers, suggesting endogenous formation of nitrosamines by bacterially reduced nitrate and endogenous amines. The urological long-term results of ureterosigmoidostomy are similar to those of conduits. However, the increased incidence of colon carcinoma is not yet proved to be higher than in conduits.

PURPOSE: The occurrence of neoplasia after ureterosigmoidostomy is well-documented in the literature. Because of its rarity, few general surgeons will gain significant exposure to this entity, and colorectal surgeons are likely to be involved with the care of these patients. The purpose of this article is to apprise colorectal surgeons about the management of neoplasia after ureterosigmoidostomy and to familiarize them with the unique anatomy of the reconstructed pelvis. METHODS: We performed a MEDLINE search to identify articles on ureterosigmoid tumors. The theories regarding the cause and pathology of these tumors were critically analyzed. A consensus was developed for screening patients with ureterosigmoidostomy and for treatment of neoplasia. RESULTS: The incidence of carcinoma after ureterosigmoidostomy ranges from 2 to 15 percent. Polyps are more common, and it seems that these tumors also follow the sequence of adenocarcinoma that is seen in the common variety of colorectal neoplasia. Neoplastic changes begin with the interaction of urine and feces and the healing colonic mucosa. Both production of nitrosamines by the action of bacteria on urine and DNA damage caused by reactive oxygen radicals produced by neutrophils at the healing anastomosis have been implicated in the pathogenesis of neoplasia. The latent period between formation of ureterosigmoidostomy and the appearance of carcinoma is between 20 and 26 years. Obstructive urinary symptoms that develop more than two years after ureterosigmoidostomy should be viewed with suspicion. The patient should be investigated with a CT scan and colonoscopy, and a barium enema may be required to delineate the anatomy further. If a benign tumor is encountered during colonoscopy, it may be removed by snare polypectomy. For a malignant tumor the segment of colon with ureteric implants should be excised, along with its lymphatic drainage. Bowel continuity is restored primarily, and the ureters are implanted in an ileal conduit. CONCLUSIONS: Patients with ureterosigmoidostomy should be followed closely for the rest of their lives. The aim of screening is to identify and treat neoplasia before malignancy develops. Furthermore, early detection of neoplasia by close screening will improve survival. Although urine cytology and occult blood are inexpensive tests, colonoscopy remains the criterion standard for follow-up of these patients. Annual colonoscopic surveillance should be started soon after the ureterosigmoidostomy but not later than five to six years after the procedure. Patients who are noncompliant with the vigorous follow-up schedule should be offered the option of resection of the colonic segment at risk with urinary diversion.