Objectives: Locally advanced and metastatic prostate cancer eventually progresses in spite of complete androgen blockade. Second-line therapy is usually disappointing, and further progression is the rule. Laboratory and clinical data have indicated that antiandrogen withdrawal may be a valuable strategy in the treatment of these patients. However, after antiandrogen withdrawal, controversial clinical results have been reported. Therefore every contribution to this therapeutic strategy is useful.
Methods: Herein we present our experience with antiandrogen discontinuation in a series of 44 patients with locally advanced or metastatic prostate cancer treated with complete androgen blockade (CAB).
Results: Prostate-specific antigen (PSA) decline was observed in 13 of 44 (29%) and in 11 of these patients the reduction was greater than 50%. No response or further progression after antiandrogen withdrawal was observed in 31 of the 44 patients (71%). Among these patients 14 died due to prostate cancer after a mean period of 5.6 months. No patient in the responding group has died.
Conclusions: Our data indicate that approximately 30% of patients with advanced prostate cancer treated with CAB respond to antiandrogen withdrawal with a reduction in serum PSA levels. Even though it is not clear whether this PSA reduction produces a benefit in terms of survival, we feel that antiandrogen withdrawal must be the first therapeutic maneuver in patients with advanced prostate cancer who progress after CAB. If there is no PSA response within 4 months, second-line treatment is necessary.