Prognostic Value of the WHO1973 and WHO2004/2016 Classification Systems for Grade in Primary Ta/T1 Non–muscle-invasive Bladder Cancer: A Multicenter European Association of Urology Non–muscle-invasive Bladder Cancer Guidelines Panel Study

In the current European Association of Urology (EAU) non-muscle-invasive bladder cancer (NMIBC) guideline, two classification systems for grade are advocated: WHO1973 and WHO2004/2016.To compare the prognostic value of these WHO systems.Individual patient data for 5145 primary Ta/T1 NMIBC patients from 17 centers were collected between 1990 and 2019. The median follow-up was 3.9 yr.Univariate and multivariable analyses of WHO1973 and...