Chemoprevention of superficial bladder cancer

Prevention of Bladder Cancer: A Review

INTRODUCTION

Bladder cancer represents an ideal tumor model to test and apply cancer prevention strategies. In addition to reviewing the epidemiology of transitional cell carcinoma (TCC), we review the current status and the future directions of bladder cancer prevention.

MATERIALS AND METHODS

A literature review of peer-reviewed articles which address bladder cancer prevention was performed.

RESULTS

Pre-clinical and limited clinical data suggest that bladder cancer is responsive to efforts to delay or prevent its development in at-risk patients, and in reducing the risk of recurrence in patients with established disease. Many epidemiologic studies, however, investigating natural products, such as vitamins and herbal compounds, lack conclusive evidence of their chemopreventive effects.

CONCLUSIONS

While many agents hold promise in the prevention of bladder cancer, none currently can be recommended as proven chemoprevention strategies. Improving the accuracy of patient risk assessment and identification of surrogate endpoint biomarkers are crucial to the testing of these strategies. Efficient study design will ensure rapid and substantial advances in the chemoprevention of bladder cancer.

Origin of multifocal carcinomas of the bladder and upper urinary tract: molecular analysis and clinical implications

The simultaneous or metachronous development of multifocal tumors with identical or variable histological features in the urothelial tract in a single patient is a well-known characteristic of urothelial cancer. To explain this phenomenon, two distinct concepts have been proposed: the 'field defect' hypothesis according to which urothelial cells in patients are primed to undergo transformation by previous carcinogenic insults and the 'single progenitor cell' hypothesis, which asserts that the multifocal development is caused by the seeding or intraepithelial spread of transformed cells. Results of recent molecular genetic studies support the 'single progenitor cell' hypothesis, and indicate that the genetic and phenotypic diversity observed in multifocal urothelial tumors is a consequence of clonal evolution from a single transformed cell. An understanding of the mechanism of the heterotopic recurrence of urothelial cancer may provide new prospects for early molecular detection and prevention of heterotopic recurrence of urothelial cancer.

Chemoprevention of superficial bladder cancer

Patients who have bladder cancer with superficial disease are at high risk for recurrence but low risk for progression to muscle invasive disease and are regularly monitored with cystoscopy to detect recurrent tumors. This clinical setting (high recurrence rate, excellent surveillance, and low risk of progression in stage) provides an ideal setting for secondary chemoprevention. Vitamins, difluoromethylornithine, and cyclooxygenase inhibitors have demonstrated activity in preclinical models of bladder cancer. Limited clinical data suggests that vitamins and their analogs may be useful for decreasing the rate of tumor recurrence in patients with superficial bladder cancer. Ongoing clinical trials are exploring the roles of fenretinide, difluoromethylornithine, and celecoxib in the treatment of patients with a history of superficial bladder cancer.