A Phase II Study of the Use of MRI-defined Focal Boosts With Stereotactic Body Radiotherapy for Localized Prostate Cancer
External beam radiotherapy combined with androgen deprivation therapy is a standard treatment option for localized prostate cancer. The current standard involves delivering radiotherapy uniformly throughout the prostate gland in daily fractions, five days per week, for approximately four weeks. In this study, radiotherapy will be delivered using an ultra-hypofractionated approach in three larger fractions on alternating days over one week Multiparametric magnetic resonance imaging will be used to guide focal dose escalation to parts of the gland harboring tumor, which could potentially reduce the risk of cancer recurrence compared to standard dose of radiotherapy. The aim of this study is to confirm that this approach can be delivered safely, that is, with rates of urinary and bowel side effects at 1 year of follow-up that are not significantly greater than the current standard.
• Histologically confirmed adenocarcinoma of the prostate
• Unfavourable intermediate-risk or high-risk localized disease
• Unfavourable intermediate-risk prostate cancer is defined as intermediate-risk prostate cancer \[that is, no high-risk features and one or more intermediate-risk factors: T2b-T2c, Gleason 3+4 (grade group 2) or Gleason 4+3 (grade group 3), or PSA 10-20 μg/L\] and one or more of the following: 2 or 3 intermediate-risk factors; Gleason 4+3 (grade group 3); ≥ 50% biopsy cores positive
• High-risk localized prostate cancer is defined as at least one of the following: T3a-T3b; Gleason ≥ 8 (grade group 4 or grade group 5); PSA \> 20 μg/L
• 3 Tesla prostate MRI done no more than 12 months prior to enrollment
• ECOG performance status 0-2
• Age ≥ 18 years
• Written informed consent
• The participant has planned androgen deprivation therapy that meets one of the following criteria:
• Patients with intermediate-risk localized prostate cancer who have planned androgen deprivation therapy consisting of up to 6 months of triptorelin with or without bicalutamide; OR patients with high-risk localized prostate cancer who have planned androgen deprivation therapy consisting of up to 24 months of triptorelin with or without bicalutamide.
• Completion of all appropriate investigations prior to enrollment