Prostate cancer is the most common solid cancer affecting male patients worldwide. When diagnosed early, it can usually be cured with surgery (radical prostatectomy), but this procedure is associated with side effects such as urinary incontinence and erectile dysfunction. If the nerves that surround the prostate are left intact (nerve-sparing), the risk of developing these side effects decreases. However, since these nerves are in intimate contact with the prostate there is a chance of leaving cancer cells behind, with the subsequent need for additional treatments. Sadly, the current methods surgeons use to select patients who can safely be offered nerve-sparing are not very accurate in predicting where the tumour is extending outside the prostate.

NeuroSAFE is a technique that can inform the surgeon if there are tumour cells on the surface of the prostate and indicate the need for removing more tissue during the same operation. However, it requires a specialised team to process the sample in a reasonable amount of time that does not excessively prolong the surgery. Therefore, many centres are not able to perform it.

A new technology called fluorescence confocal microscopy (LaserSAFE) can be used to examine the surface of the prostate and can identify when cancer is present. Critically, it requires minimal training and resources to produce results in a few minutes and the microscope can be placed in the operating room.

The investigators aim to recruit a group of 20 patients who will undergo radical prostatectomy as a treatment for prostate cancer. The prostate specimen will be analysed using both techniques, but decisions on how much tissue to resect during surgery will depend on the results of NeuroSAFE. This feasibility study will allow us to understand the challenges associated with performing both techniques. This will allow us to plan a larger study to evaluate the accuracy of LaserSAFE.

This trial will be a multi-site, single-blinded, prospective, feasibility study. 20 participants will be recruited from 2 centres that have experience performing the NeuroSAFE technique. Participants will undergo a robotic-assisted radical prostatectomy with nerve-sparing guided by the NeuroSAFE technique. Before the prostate is sent for evaluation the LaserSAFE technique will be used to analyse the corresponding posterolateral surfaces of the prostate. Participating pathologists involved in interpreting the results of NeuroSAFE will be blinded to the LaserSAFE results, to avoid influencing standard patient treatment, management, and progression outcomes after radical prostatectomy.

Inclusion Criteria:

• Patients diagnosed with operable cT2-T3a N0 M0 prostate cancer.
• Patients who underwent a multiparametric magnetic resonance imaging (MRI) before or after prostate biopsy.
• Medically fit to undergo radical prostatectomy.
• Scheduled for robot-assisted radical prostatectomy with a recommendation against nerve sparing on at least 1 side based on multidisciplinary meetings informed by MRI, biopsy result and clinical factors.
• Ability to read English sufficiently to understand the patient information sheet and to give informed consent.

Exclusion Criteria:

• • Patients who received neo-adjuvant treatment.

  • Patients in whom preoperative imaging shows rectal involvement or seminal vesicle invasion in which nerve sparing is deemed not feasible due to safety concerns.
  • Patients who received previous treatment for prostate cancer: External beam radiotherapy, brachytherapy, focal therapy, chemotherapy.

There are currently no plans to share individual participant data as this is a feasibility study with low number of participants

After LaserSAFE, images are acquired, they will be annotated with the study identifier only. Images will be stored and kept until the end of recruitment. Once all specimens have been evaluated using paraffin analysis, a dedicated meeting with the evaluating pathologist will be carried out. A set of images without any patient identifier will be shown in random order. A purposely built document will allow the pathologist to report the images. This meeting will be repeated with every evaluating pathologist until all images have been analysed.