Bladder cancer: imperatives for personalized medicine

Abstract

Although the age-adjusted incidence of urothelial carcinoma has stabilized or declined in developed nations as a result of tobacco and environmental regulations, the rising numbers of the elderly and the shift in the tobacco epidemic to underdeveloped and rapidly industrializing nations with less stringent environmental controls augur a major growth in the worldwide burden of this disease. Current understanding of the molecular pedigree of urothelial carcinoma indicates that the disease follows a two-pathway model. The first of these, the common non-muscle-invasive papillary disease (Ta) defined by fibroblast growth factor receptor 3 (FGFR3) mutations and Ras pathway signaling, is characterized by a very low (< 5%) incidence of progression to invasive disease and very low disease-specific mortality.The second, or more lethal form is characterized by carcinoma in situ and invasive (lamina propria or deeper) tumors featuring p53 and Rb defects with a high risk of disease-specific mortality. For high-risk non-muscle-invasive disease, optimized intravesical therapeutics, including adequate transurethral resection, peri-operative intravesical chemotherapy, adjuvant intravesical bacille Calmette-Guérin and/or timely cystectomy, are needed to minimize disease-specific mortality and maximize quality of life. In muscle-invasive organ-confined disease, surgery remains the standard of care, with neoadjuvant chemotherapy providing a survival benefit in a subset of patients. Research strategies that identify disease subsets of muscle-invasive bladder cancer that benefit or do not benefit from adjunctive chemotherapy are required to reduce the relatively high number-needed-to-treat associated with this approach. To facilitate major therapeutic progress in the disease, accelerated study of experimental therapeutics connected to a fuller portrait of the heterogeneous molecular pathophysiology of bladder cancer is needed. Effective multidisciplinary collaboration is imperative in order to implement existing knowledge, enable priority research, reduce costs, and improve on the clinically relevant endpoints of survival and quality of life.