Androgen depletion and repletion as a means of potentiating the effect of cytotoxic chemotherapy in advanced prostate cancer

Seventy-five patients with stage D-2 prostate cancer refractory to orchiectomy have been entered in a controlled trial to test whether androgen priming enhances the efficacy of chemotherapy. All patients are treated with aminoglutethimide and hydrocortisone as a means of achieving medical adrenalectomy and are given cyclic i.v. chemotherapy with cytoxan, adriamycin and 5-fluorouracil. Patients in the stimulation arm (N = 39) receive, in addition, fluoxymesterone (5 mg p.o. b.i.d.) for 3 days before and on the day of chemotherapy. A similar response rate was observed in the stimulation and control arm (83% vs 74% respectively) when the analysis was restricted to evaluable patients. When all patients were included, a significantly higher response rate was observed in the control arm (64% vs 49%, P less than 0.05) as a result of the larger fraction of unevaluable patients in the stimulation arm (41% vs 14%). Median duration of response is 9 months in the stimulation and 10 months in the control arm. Median overall survival in the stimulation and control group is 12 months and 16 months respectively. Significant toxicity consisting of exacerbation of bone pain and, in two patients, development of reversible spinal cord compression was observed following androgen priming. Our results suggest that combined medical adrenalectomy and chemotherapy are highly effective in the treatment of advanced prostate cancer. Thus far, no additional benefit has been observed with androgen priming.

Hormone stimulation and chemotherapy in advanced prostate cancer: interim analysis of an ongoing randomized trial

We report here in the interim analysis of an ongoing randomized clinical trial designed to test whether androgen priming enhances tumor chemosensitivity in men with stage D prostate cancer refractory to orchiectomy. All patients are continuously treated with aminoglutethimide and hydrocortisone, to lower adrenal androgen secretion, and are given cyclic chemotherapy. Patients in the stimulation arm receive also the synthetic androgen, fluoxymesterone, for 3 days before and on the day of chemotherapy. Of 57 patients entered to date, 41 have received adequate treatment to be evaluable. Response to therapy (objective remissions + stabilizations of disease) occurred in 17 of 18 evaluable patients (94%) randomized to the stimulation arm, and in 16 of 23 evaluable patients (70%) in the control group (p less than 0.025). Duration of response was not significantly different in the two groups (median: 9 months in the stimulation and 12 months in the control arm). With 30% of the total of 57 patients still alive, survival is not significantly different in the stimulation (median: 13 months) and control arm (median: 16 months). As expected, patients who responded to treatment lived significantly longer than those who failed to benefit. Two episodes of reversible spinal cord compression occurred during androgen administration. (The risk of this serious side effect may be reduced by performing a screening myelogram to rule out subclinical spinal metastasis). Our preliminary data suggest that androgen priming may enhance the tumoricidal effect of cytotoxic drugs in advanced prostate cancer. The lack of improvement in duration of response and survival may be explained by the large fraction of hormone-independent cells probably present in patients with tumors refractory to orchiectomy.

Evaluation of CEA and GCDFP-15 plasma level during hormonally induced cancer stimulation

Preliminary clinical trials indicate that transient stimulation of breast and prostate cancer growth by hormonal means may enhance tumor sensitivity to chemotherapy. In none of these studies, however, has an attempt been made to measure parameters that might reflect perturbations in cell kinetics induced by the treatment schedules. While conducting two, controlled, randomized clinical trials in advanced breast cancer and prostate cancer using a similar approach, we have measured plasma levels of two tumor markers, carcinoembryonic antigen (CEA) and breast gross cystic disease fluid protein (GCDFP-15). These served as a possible means of monitoring hormonal stimulation of tumor growth. Both markers failed to increase following administration of estrogens to patients with breast cancer and of androgens to men with prostatic carcinoma. In contrast, transient stimulation of tumor growth probably occurred as shown by exacerbation of symptoms and, in patients with prostate cancer, rise in acid phosphatase. We conclude that CEA and GCDFP-15 are not useful for monitoring pertubations in tumor cell kinetics induced by hormone stimulative protocols.