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.

Summary

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

Conditions

• Reccurent/Metastatic Solid Tumor Disease
• Prostate Cancer (Post Prostatectomy)
• Prostate Cancer
• Prostatic Neoplasms
• Neoplasm Recurrence, Local
• Biochemical Recurrence of Malignant Neoplasm of Prostate

Interventions

RADIATION

Standard Fractionation Post-Operative Salvage Radiotherapy (25 fractions)

Type: Radiation Description: External beam radiotherapy delivered to the prostate bed and pelvis using VMAT/IMRT techniques. Dose and Schedule: Prostate bed: 62.5 Gy in 25 fractions Pelvis: 45 Gy in 25 fractions Duration: Approximately 5 weeks

RADIATION

Hypofractionated Post-Operative Salvage Radiotherapy (20 fractions)

Type: Radiation Description: External beam radiotherapy delivered to the prostate bed and pelvis using VMAT/IMRT techniques. Dose and Schedule: Prostate bed: 52.5 Gy in 20 fractions Pelvis: 43 Gy in 20 fractions Duration: Approximately 4 weeks

DRUG

Androgen Deprivation Therapy (ADT)

Type: Drug Description: Hormonal therapy with a luteinizing hormone-releasing hormone (LHRH) agonist (e.g., goserelin) ± short-term anti-androgen. Duration: 6 to 24 months, at physician's discretion. Additional Notes: Patients with pelvic nodal disease may receive abiraterone and prednisone for 24 months as per STAMPEDE protocol.

Sponsors & Collaborators

• TerSera Therapeutics LLC

  collaborator INDUSTRY

• CHU de Quebec-Universite Laval

  lead OTHER

Principal Investigators

• Eric Vigneault, MD, MSc · CHU de Québec-Université Laval

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

MALE

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-02-28

Primary Completion

2029-12-31

Completion

2036-02-29

Countries

• Canada

Study Locations