Reducing radiation doses in prostate cancer treatment using advanced technology

A Feasibility Study of Dose De-escalation in Prostate Radiotherapy Using the Magnetic Resonance Linear Accelerator (MRL)

This study is testing whether using advanced technology can safely lower radiation doses in men with intermediate risk prostate cancer while still keeping their PSA levels under control.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 20 (estimated)
• Ages: 18 Years and up
• Sex: Male
• Sponsor: Royal Marsden NHS Foundation Trust (Academic / other)
• Locations: 1 site (Sutton, Surrey)
• Trial ID: NCT05709496 on ClinicalTrials.gov

What this trial studies

This feasibility study aims to evaluate the technical feasibility of dose de-escalation in radiotherapy for men with intermediate risk prostate cancer using a Magnetic Resonance Linear Accelerator (MR-linac). Participants will receive targeted radiotherapy with a total dose of 30Gy to the whole prostate and 45Gy to the dominant lesion, delivered in 5 fractions. The study will assess gastrointestinal and genitourinary toxicity as well as Prostate-Specific Antigen (PSA) control for up to 2 years post-treatment. A total of 20 men will be recruited, and the primary endpoint will be evaluated after 14 patients complete their treatment.

Who should consider this trial

Good fit: Ideal candidates are men aged 18 and older with intermediate risk localized prostate adenocarcinoma requiring radical radiotherapy.

Not a fit: Patients with advanced prostate cancer or those with a Gleason score higher than 4+3 may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could minimize radiation toxicity while effectively controlling prostate cancer.

How similar studies have performed: Other studies have shown promise in using advanced radiotherapy techniques, but this specific approach is novel.

Eligibility criteria

Inclusion Criteria:

* Men aged ≥18 years
* Histological confirmation of prostate adenocarcinoma requiring radical radiotherapy
* Gleason score 3+3, 3+4 or 4+3 (Grade groups 1, 2 or 3)
* MRI stage T2 or less (as staged by AJCC TNM 2018)
* MRI-visible tumour(s) of Prostate Imaging-Reporting and Data System (PIRADS) v2 grade 3 or higher on T2 and diffusion-weighted imaging and/or dynamic contrast-enhanced imaging with concordant pathology
* Tumour nodule visible on MRI occupying \<50% of prostate on any axial slice and \<50% total prostate volume
* PSA \<20 ng/ml prior to starting androgen deprivation therapy (ADT)
* Patients can be concurrently treated with androgen deprivation therapy if this would be standard of care. Luteinizing hormone-releasing hormone (LHRH) analogues or Bicalutamide are permitted. ADT is not mandatory where this would usually be omitted.
* World Health Organisation (WHO) Performance status 0-2
* Ability of the participant understand and the willingness to sign a written informed consent form.
* Ability/willingness to comply with the patient reported outcome questionnaires schedule throughout the study.

Exclusion Criteria:

* Contraindications to MRI (e.g. pacemaker, potentially mobile metal implant, claustrophobia)
* IPSS 19 or higher
* High grade disease (GG3) occult to MRI-defined lesion
* Post-void residual \>100 mls, where known
* Prostate volume \>90cc
* Comorbidities which predispose to significant toxicity (e.g. inflammatory bowel disease) or preclude long term follow up
* Unilateral or bilateral total hip replacement, or other pelvic metalwork which causes artefact on diffusion-weighted imaging
* Previous pelvic radiotherapy
* Patients needing \>6 months of ADT due to disease parameters.
* Previous invasive malignancy within the last 2 years excluding basal or squamous cell carcinomas of the skin, low risk non-muscle invasive bladder

Where this trial is running

Sutton, Surrey

• The Royal Marsden Hospital — Sutton, Surrey, United Kingdom (Recruiting)

Study contacts

• Study coordinator: Alison Tree, MBBS

Conditions Prostate Adenocarcinoma; Intermediate risk