Predictors of outcome of non-muscle-invasive and muscle-invasive bladder cancer

Bladder cancer is a major cause of morbidity and mortality. At initial diagnosis, 75% of patients present with non-muscle-invasive disease and 25% of patients have muscle-invasive or metastatic disease. Patients with noninvasive disease suffer from a high rate of recurrence and 10-30% will have disease progression. Patients with muscle-invasive disease are primarily treated with radical cystectomy, but frequently succumb to their disease despite improvements in surgical technique. In non-muscle-invasive disease, multiplicity, tumor size, and prior recurrence rates are the most important predictors for recurrence, while tumor grade, stage, and carcinoma in situ are the most important predictors for progression. The most common tool that clinicians use to predict outcomes after radical cystectomy is still the tumor-node-metastasis (TNM) staging system, with lymph node involvement representing the most important prognostic factor. However, the predictive accuracy of staging and grading systems are limited, and nomograms incorporating clinical and pathologic factors can improve prediction of bladder cancer outcomes. One limitation of current staging is the fact that tumors of a similar stage and grade can have significantly different biology. The integration of molecular markers, especially in a panel approach, has the potential to further improve the accuracy of predictive models and may also identify targets for therapeutic intervention or patients who will respond to systemic therapies.