PROSTATE-SPECIFIC ANTIGEN AFTER GONADAL ANDROGEN WITHDRAWAL AND DEFERRED FLUTAMIDE TREATMENT

Purpose: We assess the impact of deferred flutamide treatment on the serum prostate specific antigen (PSA) level in patients with localized or metastatic cancer, Materials and Methods: The study included 45 patients with localized cancer and 50 with metastatic cancer with an increasing (87) or stable (8) PSA level after gonadal androgen withdrawal. Results: Of 40 evaluable patients with localized cancer and 50 with metastatic cancer 32 (80%) and 27 (54%), respectively, had a PSA decrease of 50% or more of baseline during flutamide treatment (p = 0.014). Among patients with localized cancer actuarial analysis of freedom from PSA elevation during flutamide treatment favored those with a 50% or greater PSA decrease (p = 0.006) but in patients with metastatic cancer the analysis revealed no significant difference. Conclusions: The relative density of tumor cells that are dependent on adrenal androgen after gonadal androgen withdrawal may be greater in patients with localized cancer and deferred flutamide treatment may enhance cancer control in those with localized disease.