[How to apply follow-up in relation to risk group]

The term 'Non-muscle invasive bladder cancer' identifies a heterogeneous disease due to different natural history of its various appearances. T1 stage represents a non-predictable population, which might respond to non-operative treatment strategies or to the need of a more aggressive treatment, in order to avoid the progression to invasive, and possibly to metastatic stages. In the first year following transurethral resection of bladder (TURB), tumor recurrence is seen in up to 45% of the population; of this, 15% may progress to muscle invasive or metastatic disease, or both. In order to control the recurrence and progression and identify invasive tumors at the earliest possible stage, it is strongly necessary to define individual patient risk assessment follow-up. To obtain exact staging, besides a proper transurethral resection of bladder, a restaging transurethral resection of bladder should be performed in T1 patients. Data from literature support the immediate postoperative intravesical instillation of different chemotherapeutic agents in low-risk patients. Multifocal papillary lesions might require a more intensive adjuvant regimen, whereas intravesical immunotherapy using Bacillus Calmette-Guérin is recommended in patients at high risk of progression. Early cystectomy should be considered in patients with recurrent T1 tumors or refractory carcinoma in situ to avoid unfavorable tumor progression.