PSMA-PET Guided Radiotherapy

PSMA PET/CT has demonstrated higher sensitivity in detecting metastases than current imaging standard of care (CT and bone scan). \[18F\]DCFPyL is a promising high-sensitivity second generation PSMA-targeted urea-based PET probe. The hypothesis is that definitive radiotherapy (RT) informed by PSMA-PET findings will lead to improved cancer control outcomes compared to RT guided by conventional staging only. This study utilizes cmRCT design in companion to PERA (Partnership initiative for the Evaluation of technological innovation in Radiotherapy).

Sex

All

Minimum age

18 Years

Inclusion Criteria:

1. Enrolled in PERA (CHUM CER 17.0.32) and consented to contact for investigational trials.
2. Histological diagnosis of prostate cancer planned for curative-intent radiotherapy.
3. ECOG 0-1
4. Charlson Cormobidity Index ≤ 4
5. High-risk of distant metastases as defined by any of:

   1. Oligometastases (≤5) (regional or distant) identified on conventional staging, with ≤ 3 metastasis in any non-bone organ. For a spine metastasis, direct involvement of adjacent spinal segments would still be considered as "one" tumour. For nodal metastases, more than one involved lymph node in the same ipsilateral nodal region/chain would still count as "one" tumour. Defined nodal regions for this protocol include inguinal, external iliac, internal iliac, common iliac, retroperitoneal, hilar/mediastinal, anterior cervical, posterior cervical, and axillary. Metastases in all other organs that are within 1cm of each other will be considered as "one" tumour.
   2. Subjects with newly diagnosed high-risk (NCCN) localized prostate cancer and CAPRA score 6-10.
   3. Subjects with a prior history of treated prostate cancer (RP or RT), and biochemical failure (Phoenix-RT or\>0.2ng/ml-RP)
6. Standard staging (bone scan, CT pelvis) within 12 weeks of consent.

Exclusion Criteria:

1. Prior androgen deprivation therapy terminated \< 12 months prior to enrollment.
2. Prior or planned PET scan.

• DERIVEDBelliveau C, Saad F, Duplan D, Petit C, Delouya G, Taussky D, Barkati M, Lambert C, Beauchemin MC, Clavel S, Mok G, Igidbashian L, Gauthier-Pare AS, Nguyen TV, McLaughlin PY, Keu KV, DaSilva JN, Juneau D, Menard C. Prostate-Specific Membrane Antigen PET-Guided Intensification of Salvage Radiotherapy After Radical Prostatectomy: A Phase 2 Randomized Clinical Trial. JAMA Oncol. 2025 Dec 1;11(12):1431-1438. doi: 10.1001/jamaoncol.2025.3746. PMID 41037308
• DERIVEDPetit C, Delouya G, Taussky D, Barkati M, Lambert C, Beauchemin MC, Clavel S, Mok G, Pare AG, Nguyen TV, Duplan D, Keu KV, Saad F, Juneau D, Menard C. PSMA-PET/CT-Guided Intensification of Radiation Therapy for Prostate Cancer (PSMAgRT): Findings of Detection Rate, Effect on Cancer Management, and Early Toxicity From a Phase 2 Randomized Controlled Trial. Int J Radiat Oncol Biol Phys. 2023 Jul 15;116(4):779-787. doi: 10.1016/j.ijrobp.2022.12.055. Epub 2023 Jan 11. PMID 36639035