Phase III Adaptive Adaptive Stereostactic Body Radiotherapy (SBRT) With Dose Escalation for High-Risk Prostate Cancer

This study is testing a type of highly focused radiation treatment called SBRT (stereotactic body radiotherapy) for men with high-risk prostate cancer. Researchers want to see if adapting and potentially increasing the radiation dose improves cancer control. **You may be eligible if...** - You are male and 18 or older - You have been newly diagnosed with high-risk or very high-risk prostate cancer (based on tumor stage, Gleason/ISUP grade, or PSA level) - Your cancer has not spread to lymph nodes or other organs (confirmed by PSMA PET scan and MRI) - You have not had any prior prostate cancer treatment - You are well enough to participate (ECOG 0–2) **You may NOT be eligible if...** - Your cancer has spread to lymph nodes or distant sites - Your prostate is very large (greater than 80 cm³) - You have significant urinary symptoms (high IPSS score above 19) - You have had prior prostate procedures such as HIFU, cryotherapy, or a TURP - You have had prior pelvic radiation - You have chronic inflammatory bowel disease or recent serious heart problems Talk to your doctor to see if this trial is right for you.