Radiotherapy Image Guided

The goal of this clinical trial is to evaluate whether the addition of pelvic radiotherapy to androgen deprivation therapy (ADT) can delay disease progression and improve survival outcomes in patients with pathologically confirmed regional lymph node-positive (pN1) prostate cancer after radical prostatectomy. The main questions it aims to answer are: * Does ADT combined with pelvic radiotherapy improve biochemical recurrence-free survival (bRFS) compared with ADT alone in pN1 patients? * Does the addition of pelvic radiotherapy improve clinical progression-free survival, metastasis-free survival, overall survival, and prostate cancer-specific survival without unacceptable toxicity? Researchers will compare ADT plus pelvic radiotherapy with ADT alone to see if combined treatment improves disease control and long-term clinical outcomes. Participants with positive lymph nodes after prostatectomy will be randomly assigned in a 2:1 ratio to receive ADT plus pelvic radiotherapy, or ADT alone. ADT will be administered for 2 years. Patients with radiologically detectable pelvic recurrence or distant metastases after radical prostatectomy will be excluded. Safety, adverse events, and health-related quality of life will be assessed during follow-up.

This study will evaluate the feasibility of using this novel patient position monitoring system for patients receiving radiation therapy to targets involving the chest or upper abdomen, as these are the most affected by respiratory motion. This motion monitoring system will be incorporated with standard of care on-board CT imaging to confirm that the respiratory position is tracking the tumor target appropriately.