Androgen suppression combined with elective nodal irradiation and dose escalated prostate treatment: A non-inferiority, phase III randomized controlled trial of stereotactic body radiation therapy versus brachytherapy boost in patients with unfavourable risk localized prostate cancer (ASCENDE-SBRT; CCTG PR24; NCT06235697).
Background: External beam radiotherapy (EBRT), brachytherapy boost and androgen deprivation therapy (ADT) is the evidence-based standard of care for unfavourable (unfavourable intermediate, high and very high) risk non-metastatic prostate cancer. Preliminary data demonstrate that treatment with 5 fractions of stereotactic body radiotherapy (SBRT) delivered to the pelvis and prostate with ADT is efficacious and tolerable in this patient population (Murthy Int J Rad Onc Biol Phys 2025) Other potential advantages associated with this treatment strategy include fewer treatment visits, lower cost, avoidance of a general anesthetic and decreased resource utilization. Rigorous evaluation of this treatment strategy within a clinical trial is required to inform adoption in practice. Methods: PR24 is a Canadian Cancer Trials Group led, intergroup, randomized phase III, non-inferiority study comparing pelvic EBRT + brachytherapy boost to SBRT (5 fractions delivering 40Gy to prostate and 25Gy to pelvis) in brachytherapy eligible, unfavourable risk, non-metastatic prostate cancer patients. All patients will receive risk-adapted duration of ADT. The primary objective is to determine if SBRT is non-inferior to conventional EBRT with brachytherapy boost in terms of disease progression free survival (PFS). Secondary objectives include a comparison between arms of: safety and tolerability; efficacy including PSA response rate at 4 years, metastasis-free survival, prostate cancer cause-specific survival, overall survival; patient-reported and economic outcomes. Biobanking for future correlative studies is included in study design. Statistical design: The target accrual is 710 patients over 3.6 years with 5-year follow-up up to rule out a target HR 1.65 (6.5% inferiority difference at 5-years) in PFS, using type 1 error rate 5% (one sided) and 80% power with 5% lost to follow-up. Conduct to Date: Study activation - March 2024. First patient enrolled - April 2024. Accrual to date: 45. Supported by CIHR grant #183644, NCTN grant #CA180863 and CCS grant #707213.
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Author Details
Andrew Loblaw
Sunnybrook Health Sciences Centre, Toronto, ON, Canada
Abstract Details
Meeting
2025 ASCO Annual Meeting
Session Type
Poster Session
Session Title
Genitourinary Cancer—Prostate, Testicular, and Penile
Track
Genitourinary Cancer—Prostate, Testicular, and Penile
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