Malignancy associated with ureterosigmoidostomy: detection by mucosa ornithine decarboxylase

Secondary Tumors After Urinary Diversion

It has been known that urinary diversions juxtaposing the urinary and intestinal tracts lead to increased incidence of secondary malignancies. Although tumorigenesis in ureterosigmoidostomies follows the typical course from adenomas to adenocarcinomas, secondary malignancies arising from isolated intestinal diversions are much more heterogeneous. Research over the last half century has unveiled patterns of incidence and progression, while also uncovering possible mechanisms driving the neoplastic changes. In this review, we summarize the current understanding of these unique tumors, with the hope that the knowledge gained may shed light on the etiologies of other cancers arising from the urinary and intestinal tracts.

Animal models in urinary diversion

We set out to critically assess the value of animal experimentation in urinary diversion through intestinal segments, as some authors question the effectiveness of animal research, criticising the methodological quality, lack of standardization, inadequate reporting and the few systematic reviews in this field. Based on a comprehensive MEDLINE literature search (MeSH database; search terms: urinary diversion, urinary reservoirs, continent, rat, dog, animal models) we retrieved and evaluated all full-length papers published in English, German, French, and Spanish languages from 1966 to 2011 reporting the use of animal models in the setting of urinary diversion. Studies were stratified according to the addressed research question. Within each category species, gender, number of animals, age at procedure, type of diversion, mortality, length of follow-up, experimental procedure and outcome were recorded and tabulated. In all, 159 articles were judged to be relevant and while there are numerous animal models only a few have been used in more than one study. Animals were used for the systematic study of new surgical techniques (93 articles) or metabolic and functional consequences of urinary reconstruction (66 articles). For the latter purpose, the most often used animal is the rat, whereas the dog model is preferred for technical experimentation. In many studies, the validity of the model is at least questionable. Animal experiments have repeatedly been conducted addressing the same question, often with striking discrepancies in outcome. Animal studies were even performed after a surgical technique had been pioneered in humans. The use of animal models in urinary diversion is far from standardized rendering the results less than ideal for comparison across studies. Due to differences in anatomy and physiology, the applicability of findings in animal experiments to clinical urology is limited. Continued effort is needed to optimise the use of animal models in experimental urology.

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.

Neoplasia after ureterosigmoidostomy

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.

Carcinogenesis. The fate of intestinal segments used in urinary reconstruction

The actual mechanism for risk of developing cancer in intestinal segments used for urinary diversion remains uncertain. The clinical and laboratory experiences are reviewed in this article. The pathogenesis is multifaceted, involving initiators and promoters of carcinogenesis. Molecular genetic technology may provide the key to decoding the mechanisms involved.

Late malignancy in bowel segments exposed to urine without fecal stream

OBJECTIVES

This study was constructed so as to screen malignant transformation after uroenteric reconstructions using bowel segments exposed to urine without fecal stream for more than 10 years.

METHODS

Follow-up data were available for 186 patients who underwent various uroenteric reconstructions using bowel segments exposed to urine without fecal stream for more than 10 years. There were 68 eligible patients with isolated rectosigmoid bladder, 23 with bladder augmentations (15 ileocystoplasty and 8 colocystoplasty), 57 with ileal ureter, and 38 with ileal loop conduit. Besides routine laboratory and radiologic investigations, urine for cytology was obtained from all patients. Moreover, endoscopy and random biopsy of the part of bowel exposed to urine were carried out in all patients.

RESULTS

Uroenteric malignancy was diagnosed in 4 patients (2%): 2 adenocarcinoma in an isolated rectosigmoid bladder, 1 transitional cell carcinoma following augmentation colocystoplasty, and 1 squamous cell carcinoma after ileal ureter. None of the patients developed tumors in ileal loop conduits.

CONCLUSIONS

Malignant changes do not only occur after ureterosigmoidostomy but are also observed after different uroenteric reconstructions not exposed to fecal stream. Hematuria, ureteral obstruction, and abnormal urine cytology are warning signs of malignancy. Routine cytology is recommended at least yearly beginning 10 years after surgery.

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.

Histological and bacteriological findings in long-term ileocystoplasty and colocystoplasty in the rat

The long-term effects of bladder reconstruction using bowel were studied in rats. Bladder surgery consisted of cystotomy and closure, ileo- or colocystoplasty, or placement of a reverse serosal (Thal) patch of ileum. At least one-third of all groups received prophylactic cefaclor, postoperatively. Monthly urine cultures were obtained, and survivors were sacrificed at 1 year. Antimicrobial therapy markedly reduced the incidence of chronic colonization after cystoplasty. However, the majority of rats in the Thal patch group remained colonized because of acquired vesicoileal fistulae. Vesical stones were often present in this group and were also seen in 6 of 43 (14%) and 3 of 33 (9%) in the ileocystoplasty and colocystoplasty groups, respectively. Transitional cell papillomas and/or hyperplasia was seen at 20 of 42 (48%) uroileal and 20 of 31 (64%) urocolonic anastomoses (p = .15). Hyperplastic lesions could not be correlated with bacteriuria. Focal nonpapillary transitional cell carcinoma was seen once in the colocystoplasty group, and low grade papillary transitional cell tumors were noted once in each of the cystostomy and ileocystoplasty groups and twice in Thal patch rats with ileovesical fistulae. These findings suggest that the rat uroenteric anastomosis is susceptible to proliferative change which is rarely malignant in nature and occurs in the presence or absence of bacteriuria.

Synchronous adenocarcinoma and transitional cell carcinoma of the bladder associated with augmentation: case report and review of the literature

We report a case of synchronous transitional cell carcinoma and adenocarcinoma in an augmented bladder 8 years after cecocystoplasty. We discuss the clinical presentation as well as current clinical and basic research concepts, and suggest that the anastomotic zone in such cases may be at risk for malignant transformation.

Mucosal proliferation characteristics in ureterosigmoidostomy: effect of calcium supplement

Ureterosigmoidostomy, frequently performed in children for urinary diversion, is a known premalignant condition. Dietary calcium supplements have been shown to normalize mucosal proliferative patterns in other human premalignant colonic conditions, which might decrease the risk of cancer. However, calcium supplementation has not been investigated in ureterosigmoidostomy. We used a rat model to study the effects of increased dietary calcium on the progression to carcinoma in ureterosigmoidostomy. Twenty-five Wister rats underwent ureterosigmoidostomy by anastomosis of bladder trigone and ureters to sigmoid, and were divided into two groups: group 1, regular diet (14); and group 2, calcium supplemented (2%) diet (11). All animals received the diet for 9 months. At death the anastomosis was weighed and examined histologically. In addition, ornithine decarboxylase (ODC), an enzyme involved in polyamine synthesis that becomes elevated in neoplastic and proliferative disorders, was determined at the anastomosis and 8 cm proximal (normal colon). All animals developed proliferative metaplastic polyposis at the anastomosis. Tumor weights were 2.6 +/- 1.1 g for group 1 and 4.8 +/- 1.2 g for group 2 (P less than .05). The ODC levels were: group 1, normal colon 78.2 +/- 15.6 and tumor 321.3 +/- 58.8 (P less than .002); and group 2, normal colon 425.8 +/- 65.4 and tumor 568.0 +/- 40.9 (P = NS). The difference between group 1 normal colon and group 2 normal colon was significant (P less than .001), as was group 1 tumor and group 2 tumor (P less than .02).(ABSTRACT TRUNCATED AT 250 WORDS)