Combination chemotherapy following adrenal suppression in androgen- independent prostate cancer.

Abstract

Recent trials with modern chemotherapy have demonstrated activity in androgen-independent prostate cancer, but all focused on patients with progression following androgen suppression or antiandrogen withdrawal. Limited data are available on the activity of chemotherapy in androgen-independent, hormone-refractory (progressing following adrenal suppression) prostate cancer. We evaluated the activity of estramustine combined with vinblastine in this subset of androgen-independent prostate cancer. From January 1995 until April 1999, 19 patients with hormone-refractory prostate cancer received estramustine 140 mg p.o., three times daily along with weekly vinblastine 5 mg/m(2). A decrease in prostate-specific antigen of 50% or more was noted in 12 patients (63.1%, 95% CI 38.3-83.7%). The median decrease in prostate-specific antigen was 71.2% (range 50.5-85.2%). None of the 7 patients with measurable soft-tissue disease showed an objective response. The median survival from onset of chemotherapy was 6 (range 1.4-27.7) months and from initiation of adrenal suppression 16.9 (range 3.8-40. 5) months. The combination of estramustine and vinblastine is capable of inducing activity in androgen-independent prostate cancer progressing after adrenal suppression. In our small sample, the survival rate was low, and we obtained no response in soft-tissue sites. Future prospective trials are needed to determine the benefit of sequential versus simultaneous incorporation of adrenal suppression with chemotherapy in the management of androgen-independent prostate cancer.