Effects of continued androgen-deprivation therapy and other prognostic factors on response and survival in phase II chemotherapy trials for hormone-refractory prostate cancer: a Southwest Oncology Group report

Abstract

Purpose: To assess the impact of prognostic factors, including continued (orchiectomy) versus discontinued androgen-suppression (nonorchiectomy) therapy, on chemotherapy response and survival of patients with hormone-refractory prostate cancer.

Methods: Analysis of five consecutive Southwest Oncology Group (SWOG) phase II chemotherapy trials was undertaken.

Results: Two hundred five hormone-refractory patients were evaluated. Eighty-four percent had been orchiectomized. The median survival durations for the nonorchiectomy and orchiectomy patients were 6 and 7 months, respectively (P = .73). In a univariate analysis, orchiectomy patients had a significantly longer median time from diagnosis to first hormone therapy (1.1 v 0.1 years, P = .003), were more likely to have had chemotherapy initiated > or = 2 years from diagnosis (75% v 56%, P = .03), had a lower incidence of liver metastases (16% v 30%, P = .05), and had lower likelihood of being black (8% v 18%, P = .05) when compared with the nonorchiectomy group. Orchiectomy patients had a marginally significant longer median time from initial hormone treatment, more prior endocrine manipulations, lower median baseline alkaline phosphatase levels, and a lower likelihood of response to chemotherapy when compared with the nonorchiectomy group. Absence of liver metastases (P = .004), hemoglobin level > or = 10 g/dL (P < .001), acid phosphatase level > or = 1.2 IU/L (P = .05), response to chemotherapy (P = .001), and > or = 2 years from initial hormone treatment (P = .01) are important factors for survival.

Conclusion: This study failed to show obvious advantages in response to chemotherapy or survival for patients with continued gonadal suppression. A prospective randomized trial is suggested to evaluate the effect of this factor on progression-free and overall survival of patients with hormone-refractory prostate cancer receiving chemotherapy.