The 1973 WHO and 2004 WHO grading systems are not equal in prediction of survival among stage T1 bladder cancer patients.

Abstract Introduction and Objectives The aim of this study was to analyse prognostic impact of tumour histological grade on survival differences between primary G2 and G3 WHO1973 stage T1 tumours which were graded as HG according to WHO2004 grading system. Patients or Materials and Methods Data from 481 patients with primary T1HG bladder cancer who were treated between 1986 and 2016 in two university centres were retrospectively reviewed. Log-rank test and Cox regression analysis was performed to compare the groups. Results 95 (19,8%) tumours were classified as G2 and 386 (80,2%) were G3. Median follow-up was 68 months. The recurrence was observed in 228 (47,5%), and progression in 109 patients (22,7%). Radical cystectomy was performed in 114 pts (23,7%) and there were 64 (13,3%) cancer specific deaths. Recurrence-free rates at 5-years follow-up for G2, G3 and all patients were 68,7%, 51,2% and 56,3% and progression-free rates were 89,3%, 73,2% and 78,1% respectively. For total observation period patients with G3 tumours presented also worse recurrence-free, and progression-free survival levels than patients with G2 tumours. In multivariate analysis, after adjustment for clinical features, the risk of recurrence and progression for G3 tumours was 1,65 and 2,42 fold higher than for G2 tumours. Conclusions It was shown that G3 T1 tumours are characterized by worse recurrence free and progression free survivals when compared to G2 cancers.