RT Journal Article
SR Electronic
T1 Comparison between 1973 and 2004/2016 WHO grading systems in patients with Ta urothelial carcinoma of urinary bladder
JF Journal of Clinical Pathology
JO J Clin Pathol
FD BMJ Publishing Group Ltd and Association of Clinical Pathologists
SP 333
OP 337
DO 10.1136/jclinpath-2021-207400
VO 75
IS 5
A1 Collà Ruvolo, Claudia
A1 Würnschimmel, Christoph
A1 Wenzel, Mike
A1 Nocera, Luigi
A1 Califano, Gianluigi
A1 Tian, Zhe
A1 Shariat, Shahrokh F
A1 Saad, Fred
A1 Chun, Felix K H
A1 Briganti, Alberto
A1 Verze, Paolo
A1 Imbimbo, Ciro
A1 Mirone, Vincenzo
A1 Karakiewicz, Pierre I
YR 2022
UL http://jcp.bmj.com/content/75/5/333.abstract
AB Aims 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.Methods 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). Kaplan-Meier plots and multivariable Cox regression models (CRMs) tested cancer-specific mortality (CSM), according to 1973 WHO (G1 vs G2 vs G3) and to 2004/2016 WHO (low-grade vs high-grade) grading systems.Results Of 35 986 patients, according to 1973 WHO grading system, 8165 (22.7%) were G1, 17 136 (47.6%) were G2 and 10 685 (29.7%) were G3. According to 2004/2016 WHO grading system, 24 961 (69.4%) were low-grade versus 11 025 (30.6%) high-grade. In multivariable CRMs, G3 (HR: 2.05, p<0.001), relative to G1, and high-grade(HR: 2.13, p<0.001), relative to low-grade, predicted higher CSM. Conversely, G2 (p=0.8) was not an independent predictor. The multivariable models without consideration of either grading system were 74% accurate in predicting 5-year CSM. After addition of 1973 WHO or 2004/2016 WHO grade, the accuracy increased to 76% and 77%, respectively.Conclusions From a statistical standpoint, it appears that the 2004/2016 WHO grading system holds a small, although measurable advantage over the 1973 WHO grading system. Other considerations, such as intraobserver and interobserver variability may represent an additional matric to consider in deciding which grading system is better.Data are available upon reasonable request. The data were extracted from the Surveillance Epidemiology and End Results database. The statistical code used can be share upon reasonable request.