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Clinical trial Recruiting at 1 site Interventional Ages 18 and up Men only

Adaptive stereotactic body radiotherapy with pelvic treatment and focal dose boost for high-risk prostate cancer

Official title: Phase III Study of Adaptive Stereostactic Body Radiotherapy With Dose-escalation on the Dominant Intraprostatic Lesion for High-risk Prostate Cancer: ORION Trial Protocol

Run by Center Eugene Marquis · NCT07189598 · Data updated 2026-11-12

This trial will try an adaptive form of focused high-dose radiation to the prostate and pelvic lymph nodes, with an extra dose to the main tumor area, for men with high-risk prostate cancer to see if it improves outcomes and cost-effectiveness compared with standard radiotherapy.

More High-risk Prostate Cancer trials

Quick facts

Study typeInterventional
Ages18 Years and up
SexMen only
Enrollment390 (estimated)
SponsorCenter Eugene Marquis
Academic / other
Locations1 site (Rennes)
StatusRecruiting
StartedMarch 2, 2026
Main results expectedApril 1, 2033
Study endsApril 1, 2033
Registry record updatedApril 30, 2026
Trial IDNCT07189598 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Adult men (≥18) with newly diagnosed, non-metastatic high or very high-risk prostate adenocarcinoma, ECOG 0–2, normal pre-treatment testosterone, able to undergo PSMA PET/CT and pelvic MRI, and willing to attend centre-based treatment and follow-up.

Probably not a fit

Patients with nodal or distant metastases, stage T4 disease, prostate volume >80 cm3, severe urinary symptoms (IPSS >19), or prior local prostate treatment are excluded and unlikely to benefit from this protocol.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This phase III randomized trial compares an adaptive stereotactic body radiotherapy (SBRT) approach that combines whole pelvic radiotherapy (WPRT) with dose escalation to the dominant intraprostatic lesion (DIL) against standard conventional or moderately hypofractionated radiotherapy. Eligible men have newly diagnosed, non-metastatic high or very high-risk prostate adenocarcinoma confirmed by PSMA PET/CT and pelvic MRI, and will receive protocol-defined imaging and hormone therapy as appropriate. The study will measure oncologic outcomes, safety, urinary and sexual function, and includes a 5-year cost-utility analysis using trial data plus the National Health Data System (NHDS). Treatments and follow-up imaging are delivered at Centre Eugène Marquis with scheduled visits to monitor efficacy and side effects.

Why it matters

Potential benefit: If successful, this approach could improve cancer control while shortening treatment time and may be more cost-effective than standard radiotherapy.

How similar studies have gone: Smaller trials and observational studies have shown promising results for SBRT and focal DIL boosting, but randomized phase III evidence specifically combining whole pelvic RT with adaptive DIL dose escalation is limited.

Who can join: the full rules

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Male.
* Age ≥ 18 years
* ECOG (Eastern Cooperative Oncology Group) performance status 0-2
* Histologically proven prostate adenocarcinoma, not previously treated
* High-risk or very high-risk according to the National Comprehensive Cancer Network (NCCN) :

  * T3a / T3b (proximal extension only),
  * and/or ISUP (International Society of Urological Pathology) grade 4-5,
  * and/or PSA (Prostate-Specific Antigen) 20ng/mL
* Non-metastatic, as proven by Prostate Specific Membrane Antigen (PSMA) positron emission tomography/computed tomography (PET/CT) and pelvic MRI (Magnetic Resonance Imaging) less than 2 months before starting hormone therapy
* Normal testosterone levels prior to hormone therapy
* Ability to give consent for inclusion in the study
* Acceptance of treatment and monitoring modalities

Exclusion Criteria:

* Presence of nodal or distant metastases
* Stage T4.
* Prostate volume \> 80 cm3.
* IPSS \>19/35.
* Previous local treatment of prostate adenocarcinoma (HIFU (High-Intensity Focused Ultrasound), cryotherapy)
* Previous TransUrethral Resection of the prostate (PTUR)).
* Previous pelvic radiotherapy.
* Chronic inflammatory bowel disease.
* Active cardiovascular comorbidities (e.g. myocardial infarction or ischemic stroke within the last 6 months).

Where it's running

  • Centre Eugène Marquis
    Rennes, France     Recruiting

Study contacts

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
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Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.