EREctile Function Preservation for Prostate Cancer Radiation Therapy (ERECT) (ERECT)

EREctile Function Preservation for Prostate Cancer Radiation Therapy (ERECT); a Prospective Phase II Trial

Single-arm phase II trial of 70 men with low- or intermediate-risk prostate cancer receiving magnetic resonance guided adaptive radiotherapy (MRgRT) in 5 fractions of 7.25 Gy, additionally sparing the neurovascular bundles, the internal pudendal arteries, the corpora cavernosa, and the penile bulb for erectile function preservation.

Study Overview

• Status: Recruiting
• Conditions: Prostate Cancer; Erectile Dysfunction Following Radiation Therapy
• Intervention / Treatment: Radiation: Neurovascular-sparing

Detailed Description

Rationale: Erectile dysfunction is a frequent side effect of external beam radiotherapy (EBRT) for prostate cancer. To date, anatomy-based treatments that are designed to spare relevant neurovascular structures such as the internal pudendal artery and neurovascular bundles have not yet been routinely implemented in clinical practice. The implementation of magnetic resonance imaging (MRI) in treatment planning and introduction of Intensity Modulated Radiotherapy (IMRT) and Volumetric Arc Therapy (VMAT) have improved treatment precision and enabled anatomy-based EBRT and neurovascular-sparing treatments. Spratt et al. have conducted a single-arm phase 2 study to investigate the effect of vascular-sparing IMRT treatments, and found a significantly improved 2-year erectile function (78%, 95% confidence interval [CI] 71-85%) compared to conventional radiotherapy (42%, 95% CI 38-45%; p<0.001) or nerve-sparing prostatectomy (24%, 95% CI 22-27%; p<0.001). In the UMCU, the state-of-the-art MRI linear accelerator (MR-Linac) has recently been introduced. This new system allows radiation delivery under high-precision MRI visualization. The MR-Linac is therefore the most suitable technique for neurovascularsparing external beam radiotherapy treatments. Such neurovascular-sparing treatments may substantially improve post-radiotherapy erectile function outcomes and can thus improve quality of life without substantially compromising oncologic outcome.

Objective: To investigate preservation of erectile function after MR-guided radiotherapy with neurovascular-sparing in patients with localized prostate cancer.

Study design: The EREctile function preservation for prostate Cancer radiation Therapy (ERECT) trial is a prospective, single-center, phase 2 trial. Patients will be treated with the MR-Linac up to 5 fractions of 7.25 Gy with neurovascular-sparing. All fractions will be delivered over the course of 2 and a half weeks.

Study population: Men with low- and intermediate-risk adenocarcinoma of the prostate, clinical stage T1c-T2c, and Gleason ≤7, and iPSA <20 µg/L (NCCN risk categories). Patients with pT1a/b tumor diagnosis after transurethral resection of the prostate (TURP) are included, patients with "bulky" iT3 tumor diagnosis are excluded. Baseline erectile function score according to the International Index of Erectile Function (IIEF-5) questionnaire of at least 17.

Intervention: All patients will receive MR-Linac treatment consisting of 5 fractions of 7.25 Gy with neurovascular sparing, Fractions will be delivered with an overall treatment time of two and a half weeks.

Main study parameters/endpoints:

Primary endpoint: the incidence of erectile dysfunction (ED) three years after treatment.

Secondary endpoints: relapse-free survival, acute and late genitourinary and gastrointestinal toxicity and patient reported quality of life.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Participants will receive neurovascular sparing MR guided radiation therapy (MRgRT) consisting of 5 fractions of 7.25 Gy. The number of fractions and duration of treatment is similar to conventional MRgRT consisting of 5 fractions of 7.25 Gy. No increase in toxicity is expected as the dose constraints for the organs at risk in the neurovascular sparing plan will be identical to the conventional plan (i.e. bladder, rectum, femoral head and anal sphincter). For neurovascular sparing treatment, the protocol is extended with dose constraints for newly identified organs at risk (i.e. neurovascular bundles (NVB), internal pudendal arteries (IPA), corpora cavernosa (CC) and penile bulb (PB)). Attention for these organs at risk during treatment planning may reduce erectile dysfunction for the neurovascular sparing treatment. The dose to the dorsolateral part of the prostate might be lower in the NVB sparing plan as the NVB lies in close proximity to this part of the prostate. A slight dose concession on the dorsolateral part of the prostate will only be permitted if the visible tumor on multiparametric MRI is not in vicinity of the NVB as underdosage of the dominant index lesion is undesirable for tumor control. A lower dose to the dorsolateral part of the prostate may have an impact on biochemical control for certain cases, but we do not expect that it will influence overall survival.

• Study Type: Interventional
• Enrollment (Estimated): 70
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Frederik R Teunissen, MD; Phone Number: +31 (0)887550474; Email: f.r.teunissen@umcutrecht.nl
• Study Contact Backup: Name: Jochem RN van der Voort van Zyp, MD PhD; Email: j.r.n.vandervoortvanzyp@umcutrecht.nl

Study Locations

• Netherlands
  • Utrecht
    • Utrecht, Utrecht, Netherlands, 3584CX
      • Recruiting
      • University Medical Center Utrecht
      • Contact: Frederik R Teunissen, MD; Email: f.r.teunissen@umcutrecht.nl
      • Principal Investigator: Ruud C Wortel, MD PhD
      • Sub-Investigator: Frederik R Teunissen, MD
      • Principal Investigator: Jochem RN van der Voort van Zyp, MD PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age ≥18 years
• Histologically proven adenocarcinoma of the prostate
• Low-risk or intermediate-risk prostate cancer according to NCCN risk categories (low risk: T1c-T2a, Gleason score ≤6, and PSA <10 µg/L; intermediate risk: T2b-T2c or Gleason score 7 or PSA 10-20 µg/L)
• Patients with pT1a/b tumor diagnosis after transurethral resection of the prostate (TURP)
• Domain score of 17-25 on the International Index of Erectile Function-5 (IIEF-5) questionnaire
• Karnofsky score of 70-100
• Written informed consent

Exclusion Criteria:

• Use of (neo-)adjuvant androgen deprivation therapy
• High-risk prostate cancer according to NCCN risk categories (T3a or Gleason score 8-10 or PSA >20 µg/L)
• Patients with "bulky" iT3 tumor diagnosis
• Previous pelvic irradiation or radical prostatectomy
• Clinical evidence of metastatic disease
• Patients who are unable to undergo MRI
• Patients who are incompetent to sign written informed consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Neurovascular-sparing 5x7.25 Gy MRgRT; MRgRT to the prostate in 5 fractions of 7.25 Gy, additionally sparing the neurovascular bundles, internal pudendal arteries, corpora cavernosa, and penile bulb	Radiation: Neurovascular-sparing; Dose reduction of the neurovascular bundles, internal pudendal arteries, corpora cavernosa, and penile bulb during 5x7.25 Gy MRgRT

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Erectile dysfuntion	Erectile function score of ≤11 on the International Index of Erectile Function (IIEF) -5 questionnaire (0=worst; 25=best)	3 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Relapse-free survival	Defined as biochemical relapse, or positive PSMA scan or clinical relapse whichever occurs first. Biochemical relapse is defined according to the Phoenix definition, i.e. a PSA greater than the current Nadir plus 2 ng/mL. Clinical relapse consists either of locoregional disease or distant metastases	3 years
Patient-reported quality of life	According to the Expanded Prostate Cancer Index Composite short form (EPIC-26) questionnaire	3 years
Acute and late gastrointestinal and genitourinary toxicity	According to the Common Terminology Criteria for Adverse Events version 5	3 years

Collaborators and Investigators

• Sponsor: UMC Utrecht
• Investigators: Principal Investigator: Jochem RN van der Voort van Zyp, MD PhD, UMC Utrecht

Publications and helpful links

General Publications

• Roy A, Green O, Brenneman R, Bosch W, Gay HA, Michalski JM, Baumann BC. Assessing Inter-Fraction Changes in The Size and Position of The Penile Bulb During Daily MR-Guided Radiation Therapy to The Prostate Bed: Do We Need to Adjust How We Plan Radiation in The Post-Radical Prostatectomy Setting to Reduce Risk of Erectile Dysfunction? Clin Genitourin Cancer. 2022 Jun;20(3):e227-e232. doi: 10.1016/j.clgc.2022.01.006. Epub 2022 Jan 11.

Study record dates

Study Major Dates

• Study Start (Actual): July 14, 2021
• Primary Completion (Estimated): August 10, 2027
• Study Completion (Estimated): August 10, 2027

Study Registration Dates

• First Submitted: April 22, 2021
• First Submitted That Met QC Criteria: April 22, 2021
• First Posted (Actual): April 27, 2021

Study Record Updates

• Last Update Posted (Actual): March 5, 2026
• Last Update Submitted That Met QC Criteria: March 3, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Prostatic Diseases; Male Urogenital Diseases; Prostatic Neoplasms
• Other Study ID Numbers: NL73192.041.20

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No