Abiraterone With Discontinuation of Gonadotropin-Releasing Hormone Analogues in Metastatic Prostate Cancer

Inclusion Criteria: * The patient must be able to provide study-specific informed consent prior to study entry * Age ≥ 18 * Eastern Cooperative Oncology Group (ECOG) Performance Status 0-2 * Pathologically proven diagnosis of prostate adenocarcinoma * Patients must have metastatic prostate cancer * Patients may have mCRPC or may have metastatic castration-sensitive disease. * Patients must be maintained on a GnRH analogue (agonist (leuprolide, goserelin, triptorelin, histrelin, deslorelin) or antagonist (degarelix)) * The patient and the investigator have decided that the next line of cancer therapy will be abiraterone plus prednisone and the initial dose of abiraterone will be 1000 mg daily. Or patients may already be on abiraterone with prednisone at a dose of 1000 mg daily along with a GnRH analogue. * Lab values meeting the following criteria * Total testosterone level of \<50 ng/dl * Total bilirubin \< 2.0 X Upper Limit of Normal (ULN) * Aspartate aminotransferase (AST) ≤ 3 X ULN * Alanine aminotransferase (ALT) ≤ 3 X ULN * Absolute Neutrophil Count \> 1.5 K/mm3 * Platelets \> 100 K/mm3 * Hemoglobin ≥ 9.0 g/dL * Calculated creatinine clearance ≥ 30 mL/min Exclusion Criteria: * History of bilateral orchiectomy * History of hypopituitarism * For patients not yet started on abiraterone with prednisone, uncontrolled hypertension (systolic blood pressure \>170 mm Hg or diastolic blood pressure \>100 mm Hg) * Patients must not have New York Heart Association Class III or IV…