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).

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.