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

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 less than 0.001). In Ta-Tl tumours M/V index predicted progression independently (p less than 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 less than 0.0001), M/V index (p less than 0.0001), WHO grade (p less than 0.0001), papillary status (p less than 0.0001) and nuclear factors (p less than 0.0001) were significant predictors. In papillary tumours, clinical stage (p less than 0.0001), M/V index (p less than 0.0001), WHO grade (p less than 0.0001) and nuclear factors (p = 0.0001-0.0133) were related to survival. In a multivariate analysis T-category (p less than 0.001), WHO grade (p less than 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 less than 0.001) and M/V index (p less than 0.001) were independent predictors. If tumours with pelvic lymph-node metastases or distant metastases at diagnosis were excluded from the analysis, T-category (p less than 0.001), M/V index (p less than 0.001) and WHO grade (p less than 0.001) were independent predictors. In papillary tumours T-category (p less than 0.001), M/V index (p less than 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.