Mitotic activity and prognosis in prostatic adenocarcinoma.

Mitotic figures were quantitated by two different methods (number of mitotic figures in 10 high power fields, MI; number of mitotic figures/mm2 of neoplastic epithelium, M/V) in a series of 303 prostatic adenocarcinomas, and the results were related to clinical and histological features as well as to prognosis. Gleason score and mitotic indices were significantly interrelated. Invasive T3-4 tumors showed higher mitosis counts than did the local ones, and metastasis at the time of diagnosis was related to mitotic indices as well. Progression and progression-free survival were related significantly to Gleason score and mitotic indices. In univariate survival analysis, T-category, M-category, Gleason score, MI, and M/V were significant prognostic factors. In multivariate analysis, independent predictors of survival were M-category, T-category, Gleason score, patient age, and the M/V index. If the Gleason score was not included, M/V included all the available prognostic information in T1-2M0 carcinomas. The results show that, in addition to the conventional Gleason grading system, mitotic indices are useful prognostic parameters while evaluating the long-term prognosis in prostatic adenocarcinoma.