More than two-thirds of patients diagnosed with bladder cancer have tumor confined to the mucosa or lamina propria. These patients have non-muscle-invasive bladder cancer (NMIBC) amenable to interventions that preserve the bladder. This definition guides the initial management of NMIBC; however, it inadequately characterizes the natural history of the disease. Currently, up to one-third of patients with NMIBC will progress to muscle-invasive disease and have a higher risk of death from bladder cancer than those who do not progress [1].