Evaluation of the Change in PSMA Expression in Prostate Cancer in Response to Hormonal Therapy

This study is using a specialized imaging scan called a PSMA PET scan to track changes in prostate cancer before and after starting hormone therapy. PSMA is a protein found on prostate cancer cells that lights up on this scan. By taking two scans — one before and one after hormone treatment begins — researchers hope to learn how hormone therapy changes the cancer's biology, which could help doctors make better treatment decisions in the future. **You may be eligible if:** - You are a man aged 18 or older with confirmed prostate cancer - Your cancer shows uptake on an initial PSMA PET scan - You are about to start hormone therapy within 8 weeks - You fall into one of two groups: castration-resistant prostate cancer (cancer that has returned despite hormone suppression) or castration-sensitive prostate cancer (not yet treated with hormone suppression) **You may NOT be eligible if:** - Your cancer does not show uptake on PSMA PET imaging - You are not planning to start hormone therapy - You have already received certain hormone-blocking drugs recently (depending on which group applies to you) - Your life expectancy is less than 3 months Talk to your doctor to see if this trial is right for you.