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Prostate CancerEF-PRESERVENCT07916779

Erectile Function PRESERVation in Definitive Radiotherapy for Prostate Cancer by MRI-Enhanced Adaptive Sparing of the Neurovascular Bundle

A study testing Daily Adaptive MR-Enhanced SBRT with Neurovascular Bundle Sparing in people with Prostate Cancer and Localized Prostate Carcinoma, run by University of Zurich at 1 site in Switzerland.

Not yet recruiting

Opening soon. The study is approved but enrolment has not started yet. Sites may already take enquiries.

Sites and contacts
Official record
Search all trials

Trial summary

Radiotherapy is a standard and highly effective treatment for prostate cancer that is confined to the prostate gland. One modern approach, called stereotactic body radiotherapy (SBRT), delivers treatment in just five sessions and has been shown to control prostate cancer as well as longer treatment schedules. Read more about this study

Who is it for?
Ages 18 years and older, men only
What is being tested?
Daily Adaptive MR-Enhanced SBRT with Neurovascular Bundle Sparing
Could I receive a placebo?
No, everyone receives an active treatment
How many people
48 participants
Where
1 siteSwitzerland
Study dates
1 Dec 2026to 1 Dec 2033
Phase
Interventional
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • Men only
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Age ≥18 years
  • Histologically confirmed, low- or intermediate risk localized prostate cancer eligible for definitive prostate SBRT according to NCCN criteria as (Appendix 1):
  • cT1-cT2 and
  • PSA <20 ng/ml and
  • Gleason <8
  • At least at one side the DIL ≥5 mm from the NVB
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  • WHO/ECOG performance status 0-2
  • Sexually active patients (i.e. satisfactory penetrative intercourse over the last 4 weeks)
  • Life expectancy >5 years
  • If ADT planned during radiotherapy:
  • Only short-course ADT for in total ≤6 months using oral GnRH-antagonists (e.g. Relugolix) for rapid testosterone recovery.

Who cannot join

  • DIL within <5 mm to NVB at both sides
  • High risk localized prostate cancer according to NCCN criteria as:
  • cT3-cT4 or
  • PSA ≥20 ng/ml or
  • Gleason ≥8
  • Non-localized prostate cancer (i.e. cN1 or cM1)
Show all 15Show fewer
  • Insufficient erectile function preventing satisfactory penetrative intercourse (i.e. erectile dysfunction CTCAE (v6.0) Grade 3)
  • Sexually inactive patients (i.e. no penetrative intercourse over the last 4 weeks).
  • Previous pelvic radiotherapy (at any time)
  • Previous definitive treatment for prostate cancer (radiotherapy or prostatectomy at any time)
  • Contraindication to repeated MRI
  • Unable to lie in a supine position for estimated 30 min
  • Inability or contraindications to undergo the investigated intervention,
  • Clinically significant concomitant diseases,
  • Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Tiuri Kroese, MD PhD contact

+41 44 255 41 32

tiuri.kroese@usz.ch

Matthias Guckenberger, Prof. Dr. med contact

+41 44 255 29 30

Switzerland1 site

  • University Hospital Zurich

    Zurich

    Tiuri Kroese, MD PhD, +41 44 255 41 32, tiuri.kroese@usz.ch

Other trials in Switzerland

About this study

Radiotherapy is a standard and highly effective treatment for prostate cancer that is confined to the prostate gland. One modern approach, called stereotactic body radiotherapy (SBRT), delivers treatment in just five sessions and has been shown to control prostate cancer as well as longer treatment schedules. Large clinical studies have demonstrated excellent cancer control rates after SBRT.

Although SBRT is effective, some men experience worsening erectile function after treatment. Researchers believe that reducing radiation exposure to the nerves and blood vessels involved in erections, known as the neurovascular bundles (NVBs), may help preserve sexual function.

The EF-PRESERVE study is evaluating whether a specialized MRI-guided treatment approach can safely reduce radiation dose to these structures while still delivering effective treatment to the prostate cancer.

Read the detailed description

Stereotactic body radiotherapy (SBRT) has evolved from an experimental modality into a guideline-supported treatment option for localized prostate cancer. Initial pooled consortium data across 1,100 patients demonstrated high efficacy and acceptable toxicity, which was subsequently confirmed by prospective phase III trials. The HYPO-RT-PC trial established the non-inferiority of 42.7 Gy in seven fractions, while PACE-B showed that 5-fraction SBRT without androgen deprivation therapy (ADT) achieved equivalent 5-year biochemical or clinical failure-free survival compared to conventional or moderately hypofractionated schedules (95.8% vs. 94.6%). Nevertheless, erectile dysfunction remains a frequent late toxicity, with clinician-reported CTCAE Grade more than 2 erectile dysfunction rising from 18% at baseline to 26.4% five years post-SBRT in PACE-B.

To mitigate this functional decline, the EF-PRESERVE study incorporates daily adaptive magnetic resonance imaging (MRI). Because standard cone-beam computed tomography (CBCT) lacks sufficient soft-tissue resolution to visualize structures like the neurovascular bundle (NVB), the ARTEMIS workflow acts as a scaleable alternative to integrated MR-linacs.

Patients are scanned on a dedicated MRI simulator to adjust target and NVB contours daily, then transferred via a dedicated shuttle system directly to a CE-marked CBCT linear accelerator for radiotherapy delivery.

Being tested
Daily Adaptive MR-Enhanced SBRT with Neurovascular Bundle Sparing
Keywords
Stereotactic Body Radiotherapy (SBRT), Adaptive Radiotherapy (ART), MRI-Enhanced Radiotherapy, Cone-Beam Computed Tomography (CBCT), Neurovascular Bundle Sparing (NVB-Sparing), CTCAE Erectile Dysfunction
Medical subject headings
Prostatic Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Daily Adaptive MR-Enhanced SBRT with Neurovascular Bundle SparingRadiation

    Patients receive daily adaptive ultra-hypofractionated SBRT (5 fractions) utilizing the ARTEMIS workflow. Before each fraction, patients undergo low-field MRI to adapt target and neurovascular bundle (NVB) contours based on daily anatomical changes. Patients are transferred in treatment position to a standard CBCT linear accelerator via a shuttle system. Radiotherapy intentionally spares the NVB (unilaterally or bilaterally depending on tumor proximity) to preserve erectile function, while ensuring the dominant intraprostatic lesion (DIL) receives at least 40Gy. Additional erection-related structures (internal pudendal artery, penile bulb, corpus cavernosum) are contoured for dosimetric analysis. Concurrent short-course ADT (not more than 6 months), if indicated, is restricted to oral GnRH antagonists (Relugolix) to allow rapid testosterone recovery.

Study groups in NCT07916779
Study groupRoleWhat they receive
Adaptive MR-Enhanced SBRT with NVB SparingExperimentalParticipants undergo ultra-hypofractionated stereotactic body radiotherapy (SBRT) delivered in 5 fractions. Prior to each fraction, patients are imaged on a MRI simulator to evaluate and adapt target volumes and neurovascular bundle (NVB) contours. Using the ARTEMIS transfer shuttle system, patients are moved directly to a standard C-arm CBCT linear accelerator. The NVB will be spared during radiotherapy delivery while maintaining a minimum target dose of 40 Gy to the dominant intraprostatic lesion (DIL). If clinically indicated, concurrent short-course androgen deprivation therapy (under 6 months) is limited strictly to oral GnRH antagonists (e.g., Relugolix).
Receives: Radiation: Daily Adaptive MR-Enhanced SBRT with Neurovascular Bundle Sparing

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Proportion of Patients with CTCAE v6.0 Grade ≥2 Erectile Dysfunction at 1 Year Post-SBRT

    Evaluates the proportion of sexually active patients who develop clinician-reported moderate to severe erectile dysfunction (defined as CTCAE v6.0 Grade ≥2) 1 year following the completion of adaptive MR-enhanced prostate SBRT with neurovascular bundle (NVB) sparing. The rate will be evaluated against historical controls from the PACE-B trial benchmark.

    Measured: 1 year post-SBRT

Secondary outcomes (2)

  1. Patient-Reported Erectile Function Change via IIEF-5 Score

    Evaluates changes in patient-reported erectile function using the 5-item International Index of Erectile Function (IIEF-5) questionnaire. Scores range from 5 to 25, with lower scores indicating more severe erectile dysfunction (ED). The mean score change from baseline, the proportion of patients maintaining potency, and the proportion experiencing a clinically meaningful decline (≥4 point drop in IIEF-5 score) will be evaluated across time points.

    Measured: Baseline, every 3 months for the first 1 year, and annually thereafter up to 5 years post-SBRT

  2. Biochemical progression-free survival

    Measurement of PSA, biochemical progression is defined according to phoenix criteria.

    Measured: Baseline, every 3 months for the first 1 year, and annually thereafter up to 5 years post-SBRT

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted4 Nov 2026
  2. Study start1 Dec 2026 (estimated)
  3. Primary completion1 Dec 2029 (estimated)
  4. Study completion1 Dec 2033 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
48 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07916779
Sponsor's protocol ID
EF-PRESERVE
Acronym
EF-PRESERVE
Status last verified
Oct 2026
First submitted
29 Oct 2026
Last updated
4 Nov 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Undecided

Publications

  • Tutrone R, Saad F, George DJ, Tombal B, Bailen JL, Cookson MS, Saltzstein DR, Hanson S, Brown B, Lu S, Fallick M, Shore ND. Testosterone Recovery for Relugolix Versus Leuprolide in Men with Advanced Prostate Cancer: Results from the Phase 3 HERO Study. Eur Urol Oncol. 2024 Aug;7(4):906-913. doi: 10.1016/j.euo.2023.11.024. Epub 2023 Dec 23.

    PubMed 38143206

  • Shore ND, Saad F, Cookson MS, George DJ, Saltzstein DR, Tutrone R, Akaza H, Bossi A, van Veenhuyzen DF, Selby B, Fan X, Kang V, Walling J, Tombal B; HERO Study Investigators. Oral Relugolix for Androgen-Deprivation Therapy in Advanced Prostate Cancer. N Engl J Med. 2020 Jun 4;382(23):2187-2196. doi: 10.1056/NEJMoa2004325. Epub 2020 May 29.

    PubMed 32469183

  • Wilke L, Christ SM, Bello RD, Denney E, Fabiano S, Gabrys HS, Kefer K, Mayinger M, Nilo I, Perryck S, von der Grun J, Guckenberger M, Tanadini-Lang S. Safety in MR-enhanced daily adaptive SBRT Radiotherapy using a conventional C-arm linear accelerator: An FMEA approach. Z Med Phys. 2025 Nov;35(4):423-427. doi: 10.1016/j.zemedi.2025.05.002. Epub 2025 Jun 3.

    PubMed 40461359

  • Teunissen FR, Wortel RC, Hes J, Willigenburg T, de Groot-van Breugel EN, de Boer JCJ, van Melick HHE, Verkooijen HM, van der Voort van Zyp JRN. Adaptive magnetic resonance-guided neurovascular-sparing radiotherapy for preservation of erectile function in prostate cancer patients. Phys Imaging Radiat Oncol. 2021 Sep 21;20:5-10. doi: 10.1016/j.phro.2021.09.002. eCollection 2021 Oct.

    PubMed 34604553

  • Brand DH, Tree AC, Ostler P, van der Voet H, Loblaw A, Chu W, Ford D, Tolan S, Jain S, Martin A, Staffurth J, Camilleri P, Kancherla K, Frew J, Chan A, Dayes IS, Henderson D, Brown S, Cruickshank C, Burnett S, Duffton A, Griffin C, Hinder V, Morrison K, Naismith O, Hall E, van As N; PACE Trial Investigators. Intensity-modulated fractionated radiotherapy versus stereotactic body radiotherapy for prostate cancer (PACE-B): acute toxicity findings from an international, randomised, open-label, phase 3, non-inferiority trial. Lancet Oncol. 2019 Nov;20(11):1531-1543. doi: 10.1016/S1470-2045(19)30569-8. Epub 2019 Sep 17.

    PubMed 31540791

  • van As N, Griffin C, Tree A, Patel J, Ostler P, van der Voet H, Loblaw A, Chu W, Ford D, Tolan S, Jain S, Camilleri P, Kancherla K, Frew J, Chan A, Naismith O, Armstrong J, Staffurth J, Martin A, Dayes I, Wells P, Price D, Williamson E, Pugh J, Manning G, Brown S, Burnett S, Hall E. Phase 3 Trial of Stereotactic Body Radiotherapy in Localized Prostate Cancer. N Engl J Med. 2024 Oct 17;391(15):1413-1425. doi: 10.1056/NEJMoa2403365.

    PubMed 39413377

  • Nilsson P, Gunnlaugsson A, Beckman L, Widmark A, Fransson P, Hoyer M, Lagerlund M, Kindblom J, Johansson B, Bjornlinger K, Ginman C, Olsson M, Agrup M, Kjellen E, Zackrisson B, Tavelin B, Franzen L, Anderson H, Thellenberg Karlsson C. Ultra-hypofractionated versus conventionally fractionated radiotherapy for localised prostate cancer (HYPO-RT-PC): 10-year outcomes of an open-label, randomised, phase 3, non-inferiority trial. Lancet Oncol. 2026 Mar;27(3):293-301. doi: 10.1016/S1470-2045(25)00656-4. Epub 2026 Feb 5.

    PubMed 41655576

  • King CR, Freeman D, Kaplan I, Fuller D, Bolzicco G, Collins S, Meier R, Wang J, Kupelian P, Steinberg M, Katz A. Stereotactic body radiotherapy for localized prostate cancer: pooled analysis from a multi-institutional consortium of prospective phase II trials. Radiother Oncol. 2013 Nov;109(2):217-21. doi: 10.1016/j.radonc.2013.08.030. Epub 2013 Sep 20.

    PubMed 24060175

  • Spratt DE, Srinivas S, Adra N, Ahmed B, An Y, Bitting R, Chapin B, Cheng HH, Cho SY, D'Amico AV, Desai N, Dorff T, Eastham JA, Farrington TA, Gao X, Gupta S, Ippolito JE, Karnes RJ, Kishan A, Kuettel MR, Lang JM, Lee D, Lotan T, McDonald A, Morgan T, Pessoa R, Rais-Bahrami S, Roach M 3rd, Robin T, Rosenfeld S, Scarpato KR, Shabsigh A, Szmulewitz R, Teply BA, Tward J, Valicenti R, VanderWeele D, Wong JK, Kovach E, Freedman-Cass D. Prostate Cancer, Version 3.2026, NCCN Clinical Practice Guidelines In Oncology. J Natl Compr Canc Netw. 2025 Nov;23(11):469-493. doi: 10.6004/jnccn.2025.0052.

    PubMed 41213253

Questions about this trial

What is this clinical trial studying?

A study testing Daily Adaptive MR-Enhanced SBRT with Neurovascular Bundle Sparing in people with Prostate Cancer and Localized Prostate Carcinoma, run by University of Zurich at 1 site in Switzerland.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 11 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: opening soon, as of the sponsor's last update on 4 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Tiuri Kroese, MD PhD (+41 44 255 41 32, tiuri.kroese@usz.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Proportion of Patients with CTCAE v6.0 Grade ≥2 Erectile Dysfunction at 1 Year Post-SBRT (time frame: 1 year post-SBRT). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07916779, which also lists 9 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Nov 2026.

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