Next-generation SABR for prostate cancer across Ireland
INSPIRE: INnovative SABR for Prostate Cancer All IREland
This test uses focused high-dose stereotactic radiotherapy (SABR) with urethra-sparing, a rectal spacer, and nerve preservation for men with low-, intermediate-, or selected high-risk prostate cancer to try to control the tumor while reducing side effects.
Quick facts
| Phase | Phase 2 |
|---|---|
| Study type | Interventional |
| Enrollment | 136 (estimated) |
| Ages | 18 Years and up |
| Sex | Male |
| Sponsor | Cancer Trials Ireland Research network |
| Locations | 3 sites (Dublin, Leinster and 2 other locations) |
| Trial ID | NCT07552168 on ClinicalTrials.gov |
What this trial studies
This is a single-arm, multi-centre Phase II study delivering next-generation prostate SABR that prioritises the dominant intraprostatic lesion (DIL) while sparing the urethra, bladder trigone, rectum, and neurovascular bundles. Planned dosing delivers a DIL boost (40–50 Gy in 5 fractions) with lower-dose coverage to the whole prostate CTV/PTV and constrained urethral doses, and peri-rectal hydrogel spacers are placed before simulation to lower rectal dose. Treatment uses advanced image guidance with fiducials and protocol-defined dosimetric constraints, and selected intermediate/high-risk patients may receive 6–12 months of androgen-deprivation therapy at physician discretion. Patients are followed for clinical outcomes and toxicity to determine whether this approach maintains cancer control with reduced genitourinary, rectal, and sexual side effects.
Who should consider this trial
Good fit: Men aged 18 or older with biopsy-proven prostate adenocarcinoma (Gleason ≤ 4+3), clinical stage T1c–T3a, PSA ≤ 30 ng/mL, and classified as low risk, intermediate risk, or selected high-risk who are suitable for SABR and peri-rectal spacer/fiducial placement are eligible.
Not a fit: Patients with very high-risk or metastatic disease, neuroendocrine differentiation, Gleason > 4+3, PSA above eligibility limits, or who cannot undergo spacer/fiducial placement are unlikely to benefit from this protocol.
Why it matters
Potential benefit: If successful, this approach could maintain or improve cancer control while substantially reducing urinary, rectal, and sexual side effects compared with less-targeted radiotherapy.
How similar studies have performed: Previous SABR series and recent work such as the Desai POTEN-C trial have shown promising control and tolerable toxicity, but the specific combination of DIL boosting with urethra/trigone sparing and neurovascular preservation is relatively novel and being further tested.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria:
1. Written informed consent obtained prior to any study-related procedures
2. Males ≥ 18 years of age
3. ECOG performance status (PS) 0-2
4. Biopsy-proven prostate adenocarcinoma without neuro-endocrine differentiation (within 18 months prior to registration, unless on active surveillance and re-biopsy not clinically indicated)
5. Gleason score ≤ 4+3
6. Clinical and/or MRI stage T1c-T3a, N0-X, M0-X
7. PSA ≤ 30 ng/ml (within 60 days prior to registration / prior to starting androgen-deprivation therapy (ADT/hormone therapy) \[PSA ≤ 15 ng/ml for patients on 5-alpha reductase inhibitors\]
8. Patients belonging to one of the following risk groups:
* Low risk - patients meeting all of the following criteria:
* Gleason ≤ 6
* Clinical stage T1c-T2a
* PSA \< 10 ng/ml (within 60 days prior to registration)
* Intermediate risk - patients meeting any of the following criteria, assuming no high-risk features apply:
* Gleason 7 (3+4 or 4+3)
* MRI stage T2b-T2c (N0, M0-X)
* PSA 10-20 ng/ml (within 60 days prior to registration)
* High risk - patients with tumours that meet a maximum of one of the following criteria:
* MRI stage T3a (N0, M0)
* PSA \>20 - ≤30 ng/ml (within 60 days prior to registration)
Exclusion Criteria:
1. Previous malignancy within the last 2 years (except basal cell carcinoma (BCC) or squamous carcinoma of the skin), or if previous malignancy is expected to significantly compromise 5 year survival
2. Prior pelvic radiotherapy
3. Any prior active treatment for prostate cancer (with the exception of ADT). Patients previously on active surveillance are eligible if they continue to meet all other eligibility criteria.
4. Life expectancy \<5 years.
5. Bilateral hip prostheses or any other implants/hardware that would introduce substantial CT artefacts
6. Medical conditions likely to make radiotherapy inadvisable e.g. inflammatory bowel disease, significant urinary symptoms.
7. Anticoagulation with warfarin/bleeding tendency making fiducial placement or surgery unsafe in the opinion of the clinician. Note: Anti-platelet agents e.g. aspirin, clopidogrel and DOACs such as apixaban, rivaroxaban are not contraindications to trial entry.
8. Participation in another concurrent treatment protocol for prostate cancer (not including QoL, survivorship, exercise or registry studies).
Where this trial is running
Dublin, Leinster and 2 other locations
- St Luke's Centre for Radiation Oncology at Beaumont Hospital — Dublin, Leinster, Ireland (Not_yet_recruiting)
- Bon Secours - UPMC Hillman — Cork, Ireland (Recruiting)
- Northern Ireland Cancer Centre (NICC) — Belfast, Ulster, United Kingdom (Not_yet_recruiting)
Study contacts
- Study coordinator: Cancer Trials Ireland
- Email: info@cancertrials.ie
- Phone: +35316677211
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.