Prostate–Specific Antigen Levels and Clinical Response to Flutamide as the Second Hormone Therapy for Hormone–Refractory Prostate Carcinoma

Abstract

Background: Some authors have recently reported that maximum androgen block (MAB), in which the nonsteroidal anti–androgen, flutamide, is used together with conventional hormone therapy such as castration or luteinizing hormone–releasing hormone analogue, is more effective for prostate cancer than conventional methods. However, others have reported that the effect of MAB on survival is minimal, and definite conclusions concerning MAB remain unclear. Conversely, using flutamide as a second–line hormone therapy after recurrence is also considered, but few authors have reported whether this therapeutic option is effective or for which patients it is effective.Materials and Methods: 124 patients with prostate cancer were diagnosed and followed at Kobe City General Hospital between 1995 and 1997. Twenty–two of these cases developed recurrence during first–line hormone therapy, and flutamide was prescribed in these cases. The prognostic value and effectiveness of flutamide were evaluated by measurement of serum prostate–specific antigen (PSA) at diagnosis, posttreatment nadir PSA level, PSA at the time of flutamide use, histological grade, recurrence–free time after firstline hormone therapy and age at the time of diagnosis.Results: Six of 9 cases whose post–treatment nadir PSA levels after initial hormone therapy were within the normal limit (<4 ng/ml) achieved complete remission (CR) with flutamide use, but no patient whose post–treatment nadir PSA level remained elevated achieved CR. PSA at diagnosis and PSA at the start of flutamide use were significantly lower for patients with CR. However, the results of multivariate logistic regression analysis demonstrated that only the post–treatment nadir PSA level was significantly correlated with prognosis of flutamide use.Conclusions: Flutamide use as second–line hormone therapy should be limited to cases in which first–line hormone therapy has been highly effective and for whom the post–treatment nadir PSA level was within normal limits, and other patients should undergo other therapies. By limiting flutamide use to patients in whom the effect of flutamide is considered to be maximal, the incidence of complications and medication costs can be decreased.