- Patients on bisphosphonates for any cancer or on hormone therapy for prostate cancer will not need to discontinue this therapy to be eligible. However, patients with prostate cancer will need to have metastatic prostate cancer that has progressed despite hormonal therapy. Castrate testosterone levels occur within hours after castration and within 2 to 3 weeks of a luteinizing hormone-releasing hormone agonist. The current standard is to continue androgen suppression despite progressive disease.