Comparison between 1973 and 2004/2016 WHO grading systems in patients with Ta urothelial carcinoma of urinary bladder

To compare the 1973 WHO and the 2004/2016 WHO grading systems in patients with urothelial carcinoma of urinary bladder (UCUB), since no consensus has been made which classification should supersede the other and since both are recommended in clinical practice.Newly diagnosed patients with Ta UCUB treated with transurethral resection of bladder tumour were abstracted from the Surveillance, Epidemiology and End Results database (2010-2016)....