As for many other tumors it is likely that depth of invasion is a major prognostic factor for disease recurrence and progression in high grade pT1 urothelial bladder cancer. To date nor pathological anatomy based neither dimensional subclassification proved reliable correlation with recurrence and progression, mainly considering the high interobserver variability in pT1 diagnosis, biased by the TURB resection technique intrinsic artifact (tangential sectioning, thermal crush, absence of muscularis mucosae in routine specimen). A novel procedure, En Bloc TURB, can both improve the sample evaluation, especially for what concern depth of tumor invasion and margins status, and allow accurate histological based risk stratification: the possibility to analyze perfectly oriented specimen, with easily recognizable lamina propria structure and no doubt in invasion assessment, is the only way to compare tumor, and validate or disprove the role of depth of invasion in bladder cancer. Comparison of measurements will eventually reveal statistical correlation between the depth of invasion measurement and other validated clinical parameters or assess a role as independent prognostic factor for the histological parameter.
