Natural history of superficial bladder cancer. Prognostic features and long-term disease course.

Superficial bladder cancer or, more accurately, stages Ta, T1, and Tis encompass a spectrum that ranges from innocuous to life-threatening lesions. There is growing evidence that Ta grade 1 tumors rarely become invasive; although when there is associated carcinoma in situ or severe dysplasia, the risk of invasiveness increases. Carcinoma in situ is treacherous, with unpredictable behavior. Predictors of recurrence and progression are beginning to be identified for the various superficial tumors.