Pilot Study of Dose Escalation in Prostate Radiotherapy Using the MR-Linac (DESTINATION-MRL)

TRIAL POPULATION: Men with intermediate risk localized prostate cancer TRIAL TREATMENT: All radiotherapy will be delivered on the MR-linac. Intraprostatic dose will be varied according to risk of local recurrence, based on mpMRI, PSA and histology. The whole prostate will receive 30 Gy in 5 fractions and the dominant lesion plus intra-prostatic margin will receive an isotoxic 45 Gy prescription. Study rationale: The DESTINATION project aims to establish whether focusing radiation dose on the area most at risk of recurrence, and reducing the dose elsewhere, can produce a low level of side effects and maximize quality of life. This trial will assess technical feasibility of this approach. TRIAL DESIGN: DESTINATION is run as a single centre trial embedded within the Sunnybrook REB approved MOMENTUM collaboration. The MOMENTUM trial facilitates data sharing across participating institutes. Patients will be reviewed and complete toxicity assessments (CTCAE version 5) at the end of their radiation and then at 4 and 12 weeks after completion of treatment. They will thereafter be assessed at 6, 12 and 24 months with CTCAE version 5 and the patient reported IPSS assessment completed at each time point. Thereafter follow up will be as per standard care. Patient reported EPIC-26 will be measured at; baseline, 4 and 12 weeks, and 6, 12 and 24 months from the end of radiotherapy. IIEF-5 will be completed at months 6, 12 and 24. Scans will be taken before and during radiotherapy on the MR-linac. Patients will be followed up for recurrence/biochemical failure on protocol for 24 months and thereafter as per standard of care.