Potency pReservation In Prostate cAncer Patients Treated With UltraSound-guided Low-dose Rate Brachytherapy (PRIAPUS)

May 16, 2022 updated by: Lawson Health Research Institute
The purpose of this study is to develop and evaluate a Magnetic Resonance (MR) fusion 3D Ultrasound (US) guided Low dose rate (LDR) brachytherapy technique that significantly spares prostatic neurovascular bundles (a bundle of nerves and vessels that run beside the prostate) and penile bulb (base of the penis), while still trying to effectively treat the prostate cancer.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Low dose rate (LDR) brachytherapy is an excellent treatment strategy for patients with prostate confined cancers, achieving high curative rates. However, LDR brachytherapy has been linked with long-term erectile dysfunction (ED), with a broad range of reported incidence in the literature.

The pathophysiology associated with ED is complex and variable among different prostate cancer treatment strategies. In the post radical prostatectomy (RP) setting, ED is usually an immediate phenomenon and associated with neuropraxia caused by trauma and inflammation (Nandipati 2006). On the contrary, external beam radiotherapy (EBRT) related ED frequently occurs between 6-24 months and is believed to be vasculogenic in nature and caused by veno-vascular luminal occlusion (Mulhall et al. 2005) that culminates into fibrosis of the corporal tissue. In the post brachytherapy setting, seems plausible that a combination of both nerve and vascular damage are involved in the ED pathogenesis as erectile scores seem to reduce in the first months post implant (likely due to trauma) followed by a subsequent recovery and then, a gradual decline (Mabjeesh 2005).

Despite a more complex pathophysiology, rates of ED post LDR brachytherapy seem to be lower than post EBRT or RP treatment (Crook 2010, Putora 2015). This may be associated with a significantly lower degree of trauma to the surrounding healthy tissue compared with trauma caused by RP and a more conformal dose around the prostate when contrasted with EBRT. In this regard, brachytherapy delivers a lesser dose to important structures previously correlated with an erectile function such as the internal pudendal artery (IPA), penile bulb, corpus cavernosum and possibly the neurovascular bundle.

Currently, some strategies have been developed in an attempt to minimize ED post radiotherapy. In the POTEN-C clinical trial (NCT03525262), 120 patients are being randomized to stereotactic ablative radiotherapy with or without neurovascular sparing (neurovascular bundle, IPA and penile bulb/corpus carvenosum) with ED as the primary endpoint. Although the concept is intriguing, LDR brachytherapy has superior dose conformality and hence, a better chance to reduce radiation dose to the surrounding structures involved in the erectile function while still effectively treating the prostate cancer.

Study Type

Interventional

Enrollment (Anticipated)

10

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • London, Ontario, Canada, N6A 5W9
        • Recruiting
        • London Regional Cancer Program
        • Principal Investigator:
          • Lucas Mendez, MD, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

14 years to 71 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Male

Description

Inclusion Criteria:

  • Biopsy-confirmed adenocarcinoma of the prostate
  • NCCN-defined low- or favourable intermediate-risk prostate cancer patients
  • All pathological cores confined to one lobe of the prostate (minimum of 12 cores sampled), unless a recent multiparametric prostate MR-scan (mpMR) (with < 6 months from the enrollment date) indicates a dominant intra-prostatic lesion (DIL) located at the prostatic lobe where a higher number of cores and Gleason score was found positive. PIRADS v2 score 3-5 lesions are considered DILs.
  • No or mild erectile function impairment (score ≥18 in International Index of Erectile Function- 5 [IIEF-5] without PDE-5 inhibitor assistance)
  • Sexually active
  • No contraindications to prostate LDR brachytherapy

Exclusion Criteria:

  • Core positivity in both lobes of the prostate with no DIL detected on mpMR
  • mpMR suggesting presence of DILs in both lobes of the prostate
  • Contraindications to receiving a MR-scan
  • Medically unfit for general and/or spinal anesthesia
  • IPSS score > 15
  • Inflammatory bowel disease
  • Prior abdominal-perineal resection
  • Presence of distant metastases and/or nodal disease
  • Older than 75 years of age
  • Use of cytoreductive prostate treatment (including 5 alpha-reductase inhibitors)
  • NCCN-defined unfavourable intermediate or high-risk prostate cancer
  • Signs of extra-capsular extension or seminal vesicle involvement on MR-scan
  • Prior TURP
  • > 3mm of median lobe protrusion to bladder measured in mpMR (Roeloffzen 2011)
  • Prior RT to the pelvis
  • Significant artifact on MR-Scan (e.g. caused by hip prosthesis)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Prostate Cancer Patients
Low- or favourable intermediate-risk prostate cancer patients
Radiation: Low dose rate (LDR) brachytherapy
Low dose rate (LDR) brachytherapy is a type of radiation treatment where doctor places the radioactive implants (seeds) inside patient's prostate gland and these seeds emits low dose radiation over a certain period of time. During low-dose-rate brachytherapy, a continuous low dose of radiation is released over time -from several hours to several days.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Rate of patients receiving this experimental brachytherapy technique and achieving acceptable dose distribution at 1-month post-implant.
Time Frame: 1 month after intervention

Acceptable dose distribution is defined as:

  1. Target volume (Prostate, excluding a 5 mm expansion of the Neurovascular bundle) D90 ≥ 140 Gy
  2. Contralateral neurovascular bundle median dose ≤ 50 Gy
  3. Prostatic bulb D10 dose ≤ 50 Gy (Chasseray 2019)
  4. Urethra D30 < 130% of the prescription dose
1 month after intervention

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of patient with preserved erectile function Erectile Function (IIEF) >= 18)
Time Frame: 1, 6, 12, 18, 24, 36, 48, 60 months post intervention

The IIEF classifies the severity of ED into five categories stratified by score

  • No ED.26-30
  • Mild.22-25
  • Mild to moderate.17-21
  • Moderate.11-16
  • Severe.6-10
1, 6, 12, 18, 24, 36, 48, 60 months post intervention
Post-procedure PSA dynamic
Time Frame: 6, 12, 18, 24, 36, 48, 60 months post intervention
PSA curve post procedure
6, 12, 18, 24, 36, 48, 60 months post intervention
Acute and long-term GU and GI toxicity
Time Frame: 1, 6, 12, 18, 24, 36, 48, 60 months post intervention
Evaluate acute and long-term G3 or larger toxicity based on NCI-CTCAE 5.0 score system. Grade 1 to Grade 5. Higher the grade more severe is the toxicity.
1, 6, 12, 18, 24, 36, 48, 60 months post intervention
Biochemical failure
Time Frame: 1, 6, 12, 18, 24, 36, 48, 60 months post intervention
Biochemical failure will be assessed according to the Phoenix criteria (nadir + 2.0ng/mL)
1, 6, 12, 18, 24, 36, 48, 60 months post intervention
Local recurrence
Time Frame: Until study completion with 5 years of follow up
To assess the rate of biopsy-proven local recurrence
Until study completion with 5 years of follow up

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Lawson Health Research Institute

Investigators

  • Principal Investigator: Lucas Mendez, MD, London Health Sciences Centre- London Regional Cancer Program

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 1, 2021

Primary Completion (Anticipated)

December 1, 2022

Study Completion (Anticipated)

December 1, 2025

Study Registration Dates

First Submitted

November 16, 2020

First Submitted That Met QC Criteria

January 19, 2021

First Posted (Actual)

January 22, 2021

Study Record Updates

Last Update Posted (Actual)

May 17, 2022

Last Update Submitted That Met QC Criteria

May 16, 2022

Last Verified

May 1, 2022

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PRIAPUS

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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