Adaptive Radiotherapy for Safe Hypofractionation

Sponsor
Centre hospitalier de l'Université de Montréal (CHUM)
Study ID
NCT07516210
Phase
PHASE2
Status
Not Yet Recruiting

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Conditions

Eligibility Criteria

Sex
ALL
Age
N/A - N/A
Healthy Volunteers
Not accepted

Interventions

  • Adaptive Hypofractionated Radiotherapy — RADIATION
    Adaptive Radiotherapy (ART) in this study is a real-time, online daily adaptation approach in which high-resolution on-table imaging (kV-CBCT or real-time MRI) is performed prior to each fraction, with the treatment plan immediately recalculated or re-optimized using reduced PTV margins before delivery if needed, enabling safe hypofractionation through tighter margins.
  • Standard-of-care Radiotherapy — RADIATION
    Planned radiotherapy delivered according to physician discretion, without daily online contour adaptation or plan re-optimization prior to treatment delivery.

Study Details

This phase II, registry-based cohort-multiple randomized controlled trial (cmRCT) evaluates whether daily online adaptive radiotherapy (ART) enables the safe delivery of hypofractionated, iso-biologically equivalent (EQD2) external beam radiotherapy compared with standard-of-care (SOC) fractionation. Conventional radiotherapy requires generous planning target volume (PTV) margins to account for inter-fraction anatomical variation, which increases radiation exposure to surrounding organs at risk (OARs) and may contribute to toxicity. Modern ART platforms using daily on-table imaging (kV-CBCT or MRI guidance) allow real-time contour adaptation and online plan re-optimization based on same-day anatomy. This approach enables margin reduction while maintaining target coverage and may permit safe hypofractionation. Eligible patients enrolled in an institutional prospective registry will be randomized (1:1) to receive either SOC radiotherapy or hypofractionated ART across multiple pelvic disease strata (post-prostatectomy prostate cancer, intact prostate cancer, endometrial cancer, cervical cancer, and rectal cancer). The primary objective is to demonstrate non-inferiority of hypofractionated ART compared with SOC in terms of cumulative incidence of Grade ≥2 toxicity (CTCAE v5). Secondary outcomes include acute and late toxicity, oncologic outcomes (progression-free survival, locoregional failure, distant metastases, overall survival), patient-reported outcomes, treatment efficiency, and dosimetric parameters. A Bayesian monitoring framework with pre-specified safety and futility stopping rules will be used to ensure patient safety and clinical equipoise throughout the trial.

Key Dates

Start date
May 31, 2026
Status verified
Mar 2026
Primary completion
May 31, 2030
Completion
May 31, 2030

Study Design

Enrollment
264 participants (estimated)
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT

Arms

  • Active Comparator: Standard-of-care Radiotherapy
  • Experimental: Adaptive Hypofractionated Radiotherapy (ART-Hypo)

Primary Outcome Measure

Physician-reported Grade 2+ toxicity [ Time Frame: 24 months ]

Central Contacts

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