Independent clinical, histological and quantitative prognostic factors in transitional‐cell bladder tumours, with special reference to mitotic frequency

Abstract

A cohort of 537 transitional‐cell bladder cancers (TCC) was followed up for a mean of 9 years. Clinical stage, WHO grade, papillary status, 6 nuclear factors and volume‐corrected mitotic index (M/V index) were related to progression and survival. Classic and quantitative prognostic factors were significantly interrelated (p < 0.001). In Ta‐TI tumours M/V index predicted progression independently (p < 0.001) and in the entire cohort progression was related independently to the M/V index (p = 0.0001) and to the WHO grade (p = 0.0022). In survival analysis, clinical stage (p < 0.0001), M/V index (p < 0.0001), WHO grade (p < 0.0001), papillary status (p < 0.0001) and nuclear factors (p < 0.0001) were significant predictors. In papillary tumours, clinical stage (p < 0.0001), M/V index (p < 0.0001), WHO grade (p < 0.0001) and nuclear factors (p = 0.0001–0.0133) were related to survival. In a multivariate analysis T‐category (p < 0.001), WHO grade (p < 0.001), M/V index (p = 0.002) and papillary status (p = 0.034) predicted survival independently in the entire cohort whereas in papillary tumours T‐category (p < 0.001) and M/V index (p < 0.001) were independent predictors. If tumours with pelvic lymphnode metastases or distant metastases at diagnosis were excluded from the analysis, T‐category (p < 0.001), M/V index (p < 0.001) and WHO grade (p < 0.001) were independent predictors. In papillary tumours T‐category (p < 0.001), M/V index (p < 0.001) and WHO grade (p = 0.048) predicted survival. The results emphasize the importance of mitotic activity as a most important histological prognostic factor in TCC, second only to clinical stage. In Ta‐TI tumours quantitative mitotic frequency analysis includes all the available independent prognostic information. Accordingly, TCC can be graded by mitotic frequency analysis in place of subjective grading systems.