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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT04718987
Recruitment Status : Recruiting
First Posted : January 22, 2021
Last Update Posted : May 17, 2022
Information provided by (Responsible Party):
Lawson Health Research Institute

Brief Summary:
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.

Condition or disease Intervention/treatment Phase
Prostate Cancer Radiation: Low dose rate (LDR) brachytherapy Not Applicable

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.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 10 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Intervention Model Description: Prospective, single-arm clinical trial to enroll a total of 10 low- or favourable intermediate-risk prostate cancer patients.
Masking: None (Open Label)
Primary Purpose: Prevention
Official Title: Potency pReservation In Prostate cAncer Patients Treated With UltraSound-guided Low-dose Rate Brachytherapy
Actual Study Start Date : June 1, 2021
Estimated Primary Completion Date : December 2022
Estimated Study Completion Date : December 2025

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Prostate Cancer

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.

Primary Outcome Measures :
  1. 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

Secondary Outcome Measures :
  1. 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

  2. Post-procedure PSA dynamic [ Time Frame: 6, 12, 18, 24, 36, 48, 60 months post intervention ]
    PSA curve post procedure

  3. 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.

  4. 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)

  5. Local recurrence [ Time Frame: Until study completion with 5 years of follow up ]
    To assess the rate of biopsy-proven local recurrence

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   18 Years to 75 Years   (Adult, Older Adult)
Sexes Eligible for Study:   Male
Gender Based Eligibility:   Yes
Gender Eligibility Description:   Male only because this study trying to preserve the Penis erection in patients undergoing Radiation treatment for their prostate cancer.
Accepts Healthy Volunteers:   No

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)

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT04718987

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Contact: Robin Sachdeva, PhD 519-685-8500 ext 54005

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Canada, Ontario
London Regional Cancer Program Recruiting
London, Ontario, Canada, N6A 5W9
Contact: Robin Sachdeva, PhD    519-685-8500 ext 54005   
Principal Investigator: Lucas Mendez, MD, PhD         
Sponsors and Collaborators
Lawson Health Research Institute
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Principal Investigator: Lucas Mendez, MD London Health Sciences Centre- London Regional Cancer Program

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Responsible Party: Lawson Health Research Institute Identifier: NCT04718987    
Other Study ID Numbers: PRIAPUS
First Posted: January 22, 2021    Key Record Dates
Last Update Posted: May 17, 2022
Last Verified: May 2022
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Lawson Health Research Institute:
Low Dose Rate
Additional relevant MeSH terms:
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Prostatic Neoplasms
Genital Neoplasms, Male
Urogenital Neoplasms
Neoplasms by Site
Prostatic Diseases