Salvage Therapy With Bicalutamide 150 mg in Nonmetastatic Castration-resistant Prostate Cancer

ObjectivesTo evaluate the rate and duration of prostate-specific antigen (PSA) response to high-dose bicalutamide (150 mg) in nonmetastatic castration-resistant prostate cancer patients and its impact on metastasis-free survival.MethodsThis single center, prospective study included 38 prostate cancer patients surgically or medically castrated who had PSA increases above their nadir after previous antiandrogen manipulation and in absence of bone metastases. Patients were given daily dose of bicalutamide 150 mg. Clinical evaluations and serum PSA testing were performed every 3 months. Response was defined according to PSA decline from baseline as if ≥ 50% or ≥ 85%. The duration of response was the time from entering into study until PSA increased ≥ 25% or ≥ 2 ng/ml from the nadir. Bone scintigraphy was repeated at PSA increase or at symptom appearance.ResultsThe mean follow-up was 34.5 months (range, 3-75.2). A PSA decline was observed in 17 of 38 patients (44.7%): 7 (18.4%) ≥ 85% and 10 (26.3%) ≥ 50 but < 85% responders. The median duration of response was 18.5 months for partial and 37.4 months for complete responders. The median time to metastasis was 52.5 months for responders and 15.7 months for nonresponders (Log-Rank test 9.3, P = .002).ConclusionsHigh-dose bicalutamide can induce a second response in almost half of castration-resistant prostate cancer patients without metastasis. The duration of response is more than 1.5 years on average and responders have prolonged metastasis-free survival.