[Bladder urothelial carcinoma stage T1: substaging, invasion morphological patterns and its prognosis significance].

Since 1990 when the first series on substaging were published, they have published numerous publications on the invasion sublevel of high degree T1 carcinomas. The deep invasion entails a high risk of progression (around 30-35% of cases progress) as opposed to the cases of superficial invasion over "muscularis mucosae", in which the progression is around 10%, reason why most authors consider subT1, in patient management. In this revision the more exhaustive series that have evaluated substaging are shown and also the different methods to carry out this staging considering the inherent difficulty to the samples that come from transurethral resection (RTU).