How to count mitoses in bladder cancer grading?

The prognostic value of volume corrected mitotic index (M/V index) was improved in bladder cancer by correcting the M/V index for mean nuclear area (NA) in a section as an estimate of cellularity. The clinical follow-up data of 265 patients were obtained from patient files. The M/V index was counted in the biopsy specimens from the primary tumours and the NA was measured by means of IBAS 1&2 image analyser. The analysis showed that both M/V index and nuclear area corrected M/V index (MAM/V index) were related significantly to histological grade, clinical stage, papillary and progression in T-, N-, and M-categories (p less than 0.0001). In survival analysis NAM/V index was a better prognosticator (X2 = 25.5, p less than 0.0001) than M/V index (X2 = 14.4, p = 0.0007), due to better prediction of large celled high grade tumours. Recurrence-free period (RFP) was related significantly to NAM(V index (p = 0.0006) and to M/V index (p less than 0.0823)0 in that order. In conclusion, the correction of M/V index for NA as an estimate of cellularity in a section does not improve the prognostic value of M/V index in superficial bladder tumours, but it gives better grading results than the original M/V index in advanced tumours.