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

Sex

Male

Minimum age

18 Years

Inclusion Criteria:

* Histologically confirmed prostate adenocarcinoma.
* Prior radical prostatectomy with detectable PSA (≥0.2 ng/mL).
* No evidence of distant metastasis (confirmed via bone scan and CT/MRI or TEP-PSMA if PSA is above 0.5 ng /ml).
* Patient with Nodal recurrence within the pelvis are eligible
* ECOG performance status 0-2.
* Age ≥ 18 years.
* Adequate baseline renal, hepatic, and hematologic function.

Exclusion Criteria:

* Prior pelvic radiotherapy.
* Macroscopic local relapse on imaging
* Presence of metastatic disease.
* Active inflammatory bowel disease or other GI conditions predisposing to radiation toxicity.
* Uncontrolled comorbidities affecting study participation.
* Prior systemic therapy for recurrent prostate cancer (except ADT within 6 months).

• BACKGROUNDPollack A, Karrison TG, Balogh AG, Gomella LG, Low DA, Bruner DW, Wefel JS, Martin AG, Michalski JM, Angyalfi SJ, Lukka H, Faria SL, Rodrigues GB, Beauchemin MC, Lee RJ, Seaward SA, Allen AM, Monitto DC, Seiferheld W, Sartor O, Feng F, Sandler HM. The addition of androgen deprivation therapy and pelvic lymph node treatment to prostate bed salvage radiotherapy (NRG Oncology/RTOG 0534 SPPORT): an international, multicentre, randomised phase 3 trial. Lancet. 2022 May 14;399(10338):1886-1901. doi: 10.1016/S0140-6736(21)01790-6. PMID 35569466
• BACKGROUNDShipley WU, Seiferheld W, Lukka HR, Major PP, Heney NM, Grignon DJ, Sartor O, Patel MP, Bahary JP, Zietman AL, Pisansky TM, Zeitzer KL, Lawton CA, Feng FY, Lovett RD, Balogh AG, Souhami L, Rosenthal SA, Kerlin KJ, Dignam JJ, Pugh SL, Sandler HM; NRG Oncology RTOG. Radiation with or without Antiandrogen Therapy in Recurrent Prostate Cancer. N Engl J Med. 2017 Feb 2;376(5):417-428. doi: 10.1056/NEJMoa1607529. PMID 28146658
• BACKGROUNDParker CC, Kynaston H, Cook AD, Clarke NW, Catton CN, Cross WR, Petersen PM, Persad RA, Pugh CA, Saad F, Logue J, Payne H, Bower LC, Brawley C, Rauchenberger M, Barkati M, Bottomley DM, Brasso K, Chung HT, Chung PWM, Conroy R, Falconer A, Ford V, Goh CL, Heath CM, James ND, Kim-Sing C, Kodavatiganti R, Malone SC, Morris SL, Nabid A, Ong AD, Raman R, Rodda S, Wells P, Worlding J, Parulekar WR, Parmar MKB, Sydes MR; RADICALS investigators. Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial. Lancet. 2024 Jun 1;403(10442):2416-2425. doi: 10.1016/S0140-6736(24)00549-X. Epub 2024 May 16. PMID 38763153
• BACKGROUNDPetersen PM, Cook AD, Sydes MR, Clarke N, Cross W, Kynaston H, Logue J, Neville P; Patient Representative; Payne H, Parmar MKB, Parulekar W, Persad R, Saad F, Stirling A, Parker CC, Catton C. Salvage Radiation Therapy After Radical Prostatectomy: Analysis of Toxicity by Dose-Fractionation in the RADICALS-RT Trial. Int J Radiat Oncol Biol Phys. 2023 Nov 1;117(3):624-629. doi: 10.1016/j.ijrobp.2023.04.032. Epub 2023 May 6. PMID 37150260