Prognostic factors in WHO grade 2 transitional-cell bladder cancer (TCC); a novel two-grade classification system for TCC based on mitotic index.

A retrospective histological analysis has been carried out on 537 cases of transitional-cell bladder carcinoma, followed-up over a period of 9 years. In the first part of the study WHO grade 2 tumours were analysed and a number of independent factors predictive for survival identified. In a multivariate analysis the T category and M/V index (number of mitotic figures/mm2 neoplastic epithelium) were the most important prognostic factors. In a subsequent analysis of the whole series of 537 cases, overall the M/V index was not as important in predicting survival as the stage of the tumour. However, in superficial tumours (Ta-T1) subsequent analysis showed that the M/V index alone could be used to predict survival.