Stratification of stage D2 prostate cancer patients by a disease aggressiveness score and its use in evaluating disease response and outcome to combination hormonal treatment (GnRH-A plus flutamide)

Abstract

Suppression of androgen levels of stage D2 prostate cancer patients has been the prominent treatment for advanced prostate cancer. An arithmetic formula expressing disease aggressivity computed by the pre-treatment levels of alkaline phosphatase (AP), degree of tumor differentiation and number of bone metastases correlated well with disease response and outcome in stage D2 patients treated by chronic administration of the gonadotropin-releasing hormone agonistic analogues (GnRH-As; buserelin) or orchiectomy. In the present study we analyzed retrospectively disease response and outcome in 262 previously untreated stage D2 prostate cancer patients who received combination hormonal treatment (GnRH-A plus flutamide) using this aggressiveness score. Mean value of this aggressiveness score between patients who were grouped with reference to type of disease response according to the criteria established by the National Prostatic Cancer Project (NPCP) was statistically different (Kruskal-Wallis, p > 0.001). Pairwise comparison documented that this was true between all but the stable and progression groups. Linear regression analysis documented significant correlation of this aggressiveness score with length of response and survival (r = 0.59, and 0.45, respectively: p > 0.0001). Analysis of slopes obtained by linear regressions between aggressiveness score and survival in patients treated with GnRH-A plus flutamide and with GnRH-A monotherapy documented that disease response and outcome was superior among patients who received combination hormonal treatment. These data indicate that this aggressiveness score correlated well type of disease response, length of response, and survival with patients given combination hormonal treatment, and as such it can be used as an objective tool for analyzing clinical data.