NCT07516210

Adaptive Radiotherapy for Safe Hypofractionation

Adaptive Radiotherapy for Safe Hypofractionation (ART-Hypo): A Bayesian Registry-Based Randomized Controlled Trial

• Status: Not Yet Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 264 (estimated)
• Sponsor: Centre hospitalier de l'Université de Montréal (CHUM) · Academic / Other
• Sex: All
• Age: —
• Healthy volunteers: Not accepted

Summary

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.

Conditions

• Cancer
• Endometrial Cancer
• Prostate Cancer
• Cervical Cancer
• Rectal Cancers

Interventions

Type	Name	Description
RADIATION	Adaptive Hypofractionated Radiotherapy	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.
RADIATION	Standard-of-care Radiotherapy	Planned radiotherapy delivered according to physician discretion, without daily online contour adaptation or plan re-optimization prior to treatment delivery.

Timeline

• Start date: 2026-05-01
• Primary completion: 2030-05-01
• Completion: 2030-05-01
• First posted: 2026-04-07
• Last updated: 2026-04-07

Locations

1 site across 1 country: Canada