BACKGROUND: Grade of non-muscle-invasive bladder cancer (NMIBC) is an important prognostic factor for progression. Currently, two World Health Organization (WHO) classification systems (WHO1973, categories: grade 1-3, and WHO2004 categories: papillary urothelial neoplasm of low malignant potential [PUNLMP], low-grade [LG], high-grade [HG] carcinoma) are used. OBJECTIVE: To ask the European Association of Urology (EAU) and International Society of Urological Pathology (ISUP) members regarding their current practice and preferences of grading systems. DESIGN SETTING AND PARTICIPANTS: A web-based, anonymous questionnaire with ten questions on grading of NMIBC was created. The members of EAU and ISUP were invited to complete an online survey by the end of 2021. Thirteen experts had previously answered the same questions. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The submitted answers from 214 ISUP members, 191 EAU members, and 13 experts were analyzed. RESULTS AND LIMITATIONS: Currently, 53% use only the WHO2004 system and 40% use both systems. According to most respondents, PUNLMP is a rare diagnosis with management similar to Ta-LG carcinoma. The majority (72%) would consider reverting back to WHO1973 if grading criteria were more detailed. Separate reporting of WHO1973-G3 within WHO2004-HG would influence clinical decisions for Ta and/or T1 tumors according the majority (55%). Most respondents preferred a two-tier (41%) or a three-tier (41%) grading system. The current WHO2004 grading system is supported by a minority (20%), whereas nearly half (48%) supported a hybrid three- or four-tier grading system composed of both WHO1973 and WHO2004. The survey results of the experts were comparable with ISUP and EAU respondents. CONCLUSIONS: Both the WHO1973 and the WHO2004 grading system are still widely used. Even though opinions on the future of bladder cancer grading were strongly divided, there was limited support for WHO1973 and WHO2004 in their current formats, while the hybrid (three-tier) grading system with LG, HG-G2, and HG-G3 as categories could be considered the most promising alternative. PATIENT SUMMARY: Grading of non-muscle-invasive bladder cancer (NMIBC) is a matter of ongoing debate and lacks international consensus. We surveyed urologists and pathologists of European Association of Urology and International Society of Urological Pathology on their preferences regarding NMIBC grading to generate a multidisciplinary dialogue. Both the "old" World Health Organization (WHO) 1973 and the "new" WHO2004 grading schemes are still used widely. However, continuation of both the WHO1973 and the WHO2004 system showed limited support, while a hybrid grading system composed of both the WHO1973 and the WHO2004 classification system may be considered a promising alternative.

Anatomic Pathology Champalimaud Clinical Center Lisbon Portugal

Department of Cellular Pathology University Hospital of Wales Cardiff UK

Department of Laboratory Medicine and Pathobiology University of Toronto Toronto ON Canada

Department of Morphological Sciences University of Cordoba Medical School Cordoba Spain

Department of Pathology and Laboratory Medicine Brown University Warren Alpert Medical School Lifespan Academic Medical Center and Legorreta Cancer Center at Brown University Providence RI USA

Department of Pathology and Molecular Medicine Queen's University Kingston ON Canada

Department of Pathology Aquesta Uropathology and University of Queensland Brisbane Australia

Department of Pathology Cleveland Clinic Cleveland OH USA

Department of Pathology Fundació Puigvert Universitat Autónoma de Barcelona Barcelona Spain

Department of Pathology Genomic Medicine Houston Methodist Hospital and Weill Cornell Medical College Houston TX USA

Department of Pathology Medical University Vienna Vienna General Hospital Vienna Austria

Department of Surgical Oncology Netherlands Cancer Institute Antoni van Leeuwenhoek Hospital Amsterdam The Netherlands

Department of Surgical Pathology Aichi Medical University Hospital Nagakute Japan

Department of Translational Medicine Lund University Malmö Sweden

Department of Urologic Sciences University of British Columbia Vancouver BC Canada

Department of Urology Amsterdam University Medical Centers Vrije Universiteit Amsterdam The Netherlands

Department of Urology Caritas St Josef Medical Center University of Regensburg Regensburg Germany

Department of Urology Città della Salute e della Scienza University of Torino School of Medicine Torino Italy

Department of Urology Comprehensive Cancer Center Medical University Vienna Vienna General Hospital Vienna Austria

Department of Urology Fundacio Puigvert Universitat Autònoma de Barcelona Barcelona Spain

Department of Urology Hospital Clínic de Barcelona Universitat de Barcelona Barcelona Spain

Department of Urology Pitié Salpétrière Hospital AP HP GRC n°5 ONCOTYPE URO Sorbonne University Paris France

Department of Urology Skåne University Hospital Malmö Sweden

Department of Urology Teaching Hospital Motol and 2nd Faculty of Medicine Charles University Praha Prague Czech Republic

Department of Urology The Stokes Centre for Urology Royal Surrey Hospital Guildford UK

Department of Urology Université de Paris APHP Saint Louis Hospital Paris France

Department of Urology University of Texas MD Anderson Cancer Center Houston TX USA

Division of Anatomic Pathology Precision Diagnostics and Therapeutics Program Sunnybrook Health Sciences Centre Toronto ON Canada

European Association of Urology Guidelines Office Board Arnhem The Netherlands

European Association of Urology Non Muscle Invasive Bladder Cancer Guidelines Panel Arnhem The Netherlands

Institute of Pathology Friedrich Alexander University of Erlangen Nürnberg Erlangen Germany

Kingston Health Sciences Centre Queen's University Kingston ON Canada

Laboratory Medicine Program University Health Network Princess Margaret Cancer Center University of Toronto Toronto Canada

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