EVERiST: Impact of Image Detected Accessory Pudendal Artery on Erection Recovery After Nerve Sparing Prostatectomy

EVERiST: Erectile Function Recovery After Bilateral neuroVascular Bundle Sparing Robot Assisted Radical prostatEctomy in Patients With or Without an Accessory Pudendal aRtery Detected on diagnoSTic Multiparametric MRI: A Feasibility Study

Prostate cancer is the most common cancer amongst men in the United Kingdom, and two common curative treatments are surgery to remove the prostate (radical prostatectomy) or radiotherapy. Both treatments can affect quality of life, mainly because of problems with erections and urinary leakage. Many men feel disappointed or regret their treatment choice because of changes in their sexual function. Surgeons often use a 'nerve-sparing' technique to reduce the risk of erectile dysfunction (ED), but many men still experience erection problems afterwards. A way to improve erectile function recovery after surgery further would be to identify accessory (additional) arteries to the penis. Up to one in three men have an extra artery called the accessory pudendal artery (APA). Preserving this artery during surgery may improve recovery of erections by protecting blood flow and reducing the risk or severity of ED. Until recently, surgeons could only try to see these arteries during the operation, and no study has tested whether they are preserved or whether this makes a difference. This has changed with the advent of imaging. Men already have an advanced MRI scan (called a multiparametric MRI) before prostate cancer treatment. These scans can also show whether an APA is present. In addition, robotic surgery, now the gold standard for radical prostatectomy, allows operations to be video recorded. This allows comparison of what was seen on the scan with what happened during surgery and then monitoring of recovery afterwards. Early research suggests that men with an APA have better erections before surgery. This study will test whether preserving the APA during surgery helps erections recover afterwards.

In this first phase of the research (Phase 1), a feasibility study will be carried out at University College London Hospital. The study will invite 20-40 men with good sexual function before surgery, who are having robotic prostatectomy with a nerve-sparing approach. Multiparametric MRI scans will be used to identify whether an APA is present and video recordings will be collected to see if the artery was preserved. Participants will complete simple questionnaires on erections and quality of life before and after surgery up to 1 year. To assess whether the artery was preserved, an extra MRI scan will be organised after surgery for those with an APA, as well as penile ultrasound to assess erectile machinery. Ethical approval has already been obtained from the regulatory bodies, and the study is ready to start recruiting participants.

The results will allow planning of a larger, national study (Phase 2). That study will test whether preserving the APA improves erectile recovery, reduces the severity of ED, and improves quality of life. If confirmed, this research could lead to modification in surgical approach, more personalised counselling before surgery, and reduced long-term need for costly ED treatments within the NHS.

Prostate cancer is the most common cancer among men in the UK and the second leading cause of cancer-related deaths, with over 55,000 new cases diagnosed each year. It is a major health concern, but when caught early, localized prostate cancer can often be treated successfully. Treatments such as surgery (radical prostatectomy) or radiotherapy aim to cure the disease. Over the years, imaging techniques have advanced significantly. A specialized scan called multi-parametric MRI (mpMRI) is now routinely used to diagnose prostate cancer and to guide biopsies, allowing doctors to precisely target areas of concern.

Despite these advances, prostate cancer surgery, even with modern robotic-assisted techniques, can have long-lasting side effects. These include erectile dysfunction (ED) and urinary incontinence, both of which can have a significant impact on a patient's quality of life. In fact, poor sexual function is one of the most commonly reported problems after surgery, affecting many patients' mental and emotional wellbeing. Every year, around 8,000 men undergo radical prostatectomy in England through the NHS, and the majority experience some degree of these side effects.

Surgical techniques such as neurovascular bundle (NVB) sparing are designed to protect the nerves and blood vessels around the prostate that are critical for erectile function. However, recovery of erectile function after NVB-sparing surgery is unpredictable, and many patients do not regain their full sexual function. The reasons for this are not fully understood. Some experts believe that erectile dysfunction may be due to damage to blood vessels, while others suggest nerve damage is the primary cause. It's likely that both factors play a role.

One overlooked issue might be variations in pelvic anatomy. In up to 38% of men, the blood vessels that supply the penis-such as the accessory pudendal arteries (APAs)-can be in different locations than expected. These variations are often not considered during conventional nerve-sparing procedures, which focus on preserving structures behind the prostate. If these additional arteries are damaged or removed during surgery, it could contribute to erectile dysfunction.

Fortunately, new tools offer the potential to address this. High-resolution mpMRI scans, which are already part of the standard diagnostic process for prostate cancer, can map the location of these blood vessels before surgery. Additionally, robotic-assisted surgery allows surgeons to record the entire operation in detail. By analyzing these recordings alongside the pre-surgery MRI scans and post-surgery outcomes, researchers can better understand how preserving these arteries affects recovery of erectile function.

This is feasibility study aims to explore whether identifying and preserving accessory pudendal arteries during surgery can improve erectile function outcomes for prostate cancer patients. The goal is to assess whether it's feasible to incorporate these imaging and surgical techniques into regular practice. If successful, this research could guide surgeons in refining their methods, help patients make better-informed decisions, and ultimately improve recovery outcomes for men undergoing prostate cancer surgery.

This is a prospective, single-centre, non-interventional feasibility study evaluating functional and imaging outcomes in patients with localized prostate cancer undergoing bilateral neurovascular bundle (NVB)-sparing robotic-assisted radical prostatectomy (RARP) at University College London Hospitals.

The study will recruit 20-40 sexually active men, aged 18 years or older, with good baseline erectile function (IIEF-EF ≥24). All procedures will be performed by one of four designated surgeons (Mr Zafer Tandogdu, Mr Ben Lamb, Mr Ashwin Sridhar, Prof Greg Shaw) to minimise surgical variability.

Data collection: Demographics, medical history, and preoperative multi-parametric MRI (mpMRI) parameters will be recorded. Functional outcomes will be assessed using validated Patient-Reported Outcome Measures (PROMs) at baseline, 6 weeks, 6 months, and 12 months post-surgery. Standard UCLH andrology follow-up will continue, with optional telephone consultations instead of clinic visits.

Additional assessments:

• 3-month follow-up mpMRI will be performed only in participants with an accessory pudendal artery (APA) identified on their baseline mpMRI, to assess vessel patency.
• Penile Doppler ultrasound (optional) will be offered to participants considering intracavernosal injections for erectile dysfunction, both before and after surgery.

Surgical quality assessment: Intraoperative videos (routine recordings made for training) will capture only the operative field, excluding identifiable patient features. These anonymised recordings will be securely stored and reviewed by high-volume surgeons for assessment of surgical technique. Theatre staff consent procedures have been implemented to address GDPR and confidentiality.

Participation is entirely voluntary. The aim is to assess the feasibility of recruitment, data collection, and follow-up procedures to inform a larger future study.

The aim of this project is to assess the feasibility and acceptability of conducting a full-scale observational study that investigates whether imaging-detected accessory pudendal arteries (APAs) influence erectile function outcomes following nerve-sparing robot-assisted radical prostatectomy (RARP).

In other words, the main goal of this feasibility study is to test whether it is possible and practical to run a larger future study. The investigators will explore whether men can be successfully recruited and followed up, and whether imaging and surgical data can be collected and analysed in a reliable way. This will lay the groundwork for a definitive study on whether preserving APAs affects erectile recovery after prostate surgery.

Inclusion Criteria:

• Men diagnosed with cT2-T3a N0 M0 PCa aged between 18 and 79 from all ethnic backgrounds.
• Patients who underwent a prostate mpMRI before prostate biopsy.
• Medically fit to undergo RARP.
• Diagnostic quality prostate biopsies concordant with a diagnostic quality prostate mpMRI adequate to provide a surgical plan.
• Scheduled for RARP with a recommendation of NVB spare based on multidisciplinary meetings informed by mpMRI, biopsy result and clinical factors.
• Sexually active men with no to mild ED at baseline based on IIEF-EFD (>=24) questionnaire.
• Preference to preserve erectile function for sexual intercourse.
• Ability to read English sufficiently to understand PIS and able to give informed consent.

Exclusion Criteria:

• Established moderate/ severe ED (IIEF-EFD <24)
• Patients who received neo-adjuvant androgen deprivation therapy.
• Patients with previous surgery for benign prostatic enlargement
• Patients who received previous treatment for prostate cancer: External beam radiotherapy, brachytherapy, focal therapy, chemotherapy.
• Previous pelvic or penile fracture
• Previous surgery for ED
• Poor quality prostate mpMRI or biparametric MRI (no contrast)
• Established vascular disease (ischaemic heart disease, cerebrovascular disease, peripheral vascular disease)