Non-inferiority Study Comparing Salvage Pelvic Radiotherapy in 25 Fractions (62.5 Gy/25) Versus 20 Fractions (52.5 Gy/20) for Recurrent Prostate Cancer After Surgery.

Study Overview This research compares two types of post-operative salvage radiotherapy (SRT) for men with prostate cancer who have had surgery but show signs of recurrence (detectable PSA). The goal is to see if a shorter treatment schedule is as safe and effective as the standard schedule. Why is this study important? After prostate surgery, cancer can return in up to 70-80% of high-risk patients. Radiotherapy helps control this, but the best way to deliver it-especially the number of sessions and whether to treat the pelvic area-is still being studied. Shorter treatments could mean less time in therapy and better quality of life, if such treatments are proven safe. What is being compared? Standard treatment (Arm A): 25 sessions (about 5 weeks) Prostate bed: 62.5 Gy Pelvis: 45 Gy Shorter treatment (Arm B): 20 sessions (about 4 weeks) Prostate bed: 52.5 Gy Pelvis: 43 Gy Both groups may also receive hormone therapy (ADT) for 6-24 months. Main Goal To check if the shorter treatment causes no more side effects (urinary or bowel problems) than the standard treatment, while keeping cancer control similar. Other Things to be Measured Cancer control (PSA levels, spread of disease) Survival Quality of life (urinary, bowel, sexual health questionnaires) Who can join? Men who: Had prostate surgery Have a detectable PSA (≥0.2 ng/mL) No distant metastasis Are in good general health (ECOG 0-2) How long will the study last? About 12 years total: 2 years to enroll patients 10 years of follow-up

NCT Number	NCT07483658
Lead Sponsor	CHU de Quebec-Universite Laval Collaborators: TerSera Therapeutics LLC
Conditions	Reccurent/Metastatic Solid Tumor Disease, Prostate Cancer (Post Prostatectomy), Prostate Cancer, Prostatic Neoplasms, Neoplasm Recurrence, Local, Biochemical Recurrence of Malignant Neoplasm of Prostate
Enrollment	434 participants
Start Date	2026-05-13
Primary Completion	2029-12 (estimated)
Study Completion	2036-02 (estimated)
Updated on ClinicalTrials.gov	2026-07-01