LDR Brachytherapy for Prostate Cancer

(PRIAPUS Trial)

Overseen By Robin Sachdeva, PhD

Age: 18+

Sex: Male

Trial Phase: Academic

Sponsor: London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's

Must not be taking: 5 alpha-reductase inhibitors

Disqualifiers: Older than 75, Metastases, Inflammatory bowel disease, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 2 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 2

Duration: 1 month

10 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests a new method for treating prostate cancer using a specialized radiation therapy called brachytherapy. The goal is to employ an advanced imaging technique to target the cancer more precisely while avoiding important nerves and blood vessels near the prostate, potentially reducing side effects. It is designed for men with low- or favorable intermediate-risk prostate cancer that has not spread beyond one side of the prostate. Participants should have no or mild erectile function issues and be sexually active. This trial offers a potential option for those seeking precise treatment with possibly fewer side effects. As an unphased trial, it provides an opportunity to explore innovative treatment options that may offer significant benefits.

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications, but it does exclude those using cytoreductive prostate treatments, including 5 alpha-reductase inhibitors.

What prior data suggests that this technique is safe for prostate cancer patients?

Studies have shown that low-dose rate (LDR) brachytherapy, a type of radiation treatment, is generally safe and effective for prostate cancer. Research indicates that this treatment targets the prostate gland while minimizing exposure to nearby organs, resulting in fewer side effects.

Other studies reported good cancer control with low levels of harmful effects. Some patients experienced urinary problems, but these were expected and manageable.

Overall, LDR brachytherapy is well-tolerated, with a strong safety record in treating prostate cancer. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about UltraSound-guided Low-dose Rate Brachytherapy for prostate cancer because it offers a more precise and targeted approach compared to traditional treatments like surgery or external beam radiation therapy. This technique involves placing radioactive seeds directly into or near the tumor, minimizing damage to surrounding healthy tissue. This precise targeting can potentially lead to fewer side effects and a quicker recovery, making it an attractive option for patients with low- or favorable intermediate-risk prostate cancer.

What evidence suggests that this technique is effective for prostate cancer?

Studies have shown that Low-Dose-Rate (LDR) brachytherapy, which participants in this trial will receive, effectively treats prostate cancer. Research indicates that it can maintain low cancer markers in 75–95% of patients with intermediate-risk prostate cancer. This treatment delivers a high dose of radiation directly to the prostate, limiting exposure to nearby organs. This precision helps reduce potential side effects. Overall, LDR brachytherapy is a well-established option for managing prostate cancer. ^{2 3 6 7 8}

Who Is on the Research Team?

Lucas Mendez, MD

Principal Investigator

London Health Sciences Centre- London Regional Cancer Program

Are You a Good Fit for This Trial?

Men with biopsy-confirmed prostate cancer, where the disease is contained in one lobe of the prostate. They should have good erectile function and be sexually active, without severe urinary symptoms or any prior high-risk treatments for prostate cancer. Participants must be fit for anesthesia, under 75 years old, and not have inflammatory bowel disease or certain other medical conditions.

Inclusion Criteria

No or mild erectile function impairment (score ≥18 in International Index of Erectile Function- 5 [IIEF-5] without PDE-5 inhibitor assistance)

My prostate cancer is confined to one lobe, or a recent scan shows a major lesion there.

My prostate cancer was confirmed by a biopsy.

Exclusion Criteria

My prostate cancer is at an intermediate or high risk level.

Significant artifact on MR-Scan (e.g. caused by hip prosthesis)

You are unable to undergo an MRI scan due to certain medical conditions.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive MR fusion 3D Ultrasound guided Low dose rate brachytherapy to treat prostate cancer

1 month

1 visit (in-person)

Follow-up

Participants are monitored for safety, effectiveness, and erectile function post-treatment

60 months

Regular visits at 1, 6, 12, 18, 24, 36, 48, 60 months post intervention

Long-term follow-up

Participants are monitored for long-term outcomes including local recurrence and biochemical failure

5 years

What Are the Treatments Tested in This Trial?

Interventions

• UltraSound-guided Low-dose Rate Brachytherapy

Trial Overview The trial is testing a new way to do LDR brachytherapy that uses MR fusion with 3D Ultrasound guidance. The goal is to treat prostate cancer while sparing important nerves and vessels near the prostate and penile bulb to preserve sexual function.

How Is the Trial Designed?

Group I: Prostate Cancer Patients Experimental Treatment 1 Intervention

Low- or favourable intermediate-risk prostate cancer patients

UltraSound-guided Low-dose Rate Brachytherapy is already approved in United States, European Union for the following indications:

Approved in United States as Low-dose Rate Brachytherapy for:

• Localized prostate cancer
• Low-risk prostate cancer
• Favorable intermediate-risk prostate cancer

Approved in European Union as Low-dose Rate Brachytherapy for:

• Localized prostate cancer
• Low-risk prostate cancer
• Favorable intermediate-risk prostate cancer

Who Is Running the Clinical Trial?

London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's

Lead Sponsor

Trials

678

Recruited

421,000+

London Health Sciences Centre Research Institute and Lawson Research Institute of St. Joseph's

Lead Sponsor

Trials

686

Recruited

427,000+

Lawson Health Research Institute

Lead Sponsor

Trials

684

Recruited

432,000+

Published Research Related to This Trial

In a study of 102 patients undergoing prostate low-dose-rate brachytherapy, the estimated intrarectal dose rates from radioactive seeds were found to be higher for (103)Pd compared to (125)I immediately after implantation, with average rates of 2.5 cGy/h and 2.1 cGy/h, respectively.

Radiation exposure from (103)Pd decreases more rapidly than from (125)I, suggesting that patients should limit receptive anal intercourse for 2 months after (103)Pd treatment and for 6 months after (125)I treatment to minimize radiation exposure.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Radiation safety of receptive anal intercourse with prostate cancer patients treated with low-dose-rate brachytherapy. Nasser, NJ., Cohen, GN., Dauer, LT., et al.[2018]

Low-dose rate brachytherapy (LDR-BT) showed similar biochemical recurrence-free survival rates compared to radical prostatectomy (RP) after 5 years, indicating that both treatments are equally effective in preventing cancer recurrence in localized prostate cancer.

LDR-BT had a significant advantage over RP in terms of urinary incontinence (0% vs. 18% incidence), while RP was associated with more urinary irritation (80% vs. 4.5% incidence), highlighting the differing side effect profiles of these treatments.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Low-dose rate brachytherapy for men with localized prostate cancer. Peinemann, F., Grouven, U., Hemkens, LG., et al.[2022]

In a study of 201 patients treated with low-dose-rate (LDR) brachytherapy for localized prostate cancer, there was a significant and persistent decline in prostate-specific antigen (PSA) levels over time, indicating effective cancer control.

After 10 years of follow-up, only 9 patients experienced tumor recurrence, and while some urinary symptoms were noted initially, they significantly decreased after 18 months, suggesting that LDR brachytherapy is both safe and effective with manageable side effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Low-dose-rate brachytherapy as a minimally invasive curative treatment for localised prostate cancer has excellent oncological and functional outcomes: a retrospective analysis from a single centre. D'hulst, P., Mattelaer, P., Darras, J., et al.[2022]

A study involving 2237 patients with early-stage prostate cancer showed that low-dose-rate brachytherapy (LDR-BT) is highly effective, with 5-year disease-specific survival rates at 99% and overall survival rates at 94%.

The quality of the treatment, indicated by the volume of the target receiving the prescribed dose (V100), was linked to better biochemical failure-free survival, especially in patients with low-risk cancer, highlighting the importance of careful patient selection and treatment planning.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Low dose rate brachytherapy (LDR-BT) as monotherapy for early stage prostate cancer in Italy: practice and outcome analysis in a series of 2237 patients from 11 institutions. Fellin, G., Mirri, MA., Santoro, L., et al.[2022]

Low dose rate (LDR) prostate brachytherapy is a highly effective radiation treatment for non-metastatic prostate cancer, showing excellent oncologic outcomes and low rates of severe side effects (1% to 4% for late grade 3 or 4 toxicity).

This technique, which uses precise image guidance for radioactive source placement, is endorsed by expert consensus groups for all risk groups and can be performed as a same-day procedure, making it both cost-effective and convenient.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Low dose rate prostate brachytherapy. Stish, BJ., Davis, BJ., Mynderse, LA., et al.[2020]

In a study of 195 patients treated with low-dose rate brachytherapy (LDR-BT) for low-risk prostate cancer, the five-year biochemical failure-free survival (BFFS) rate was an impressive 95.7%.

The study found that the dose delivered to the prostate (D90%) was significantly linked to BFFS, indicating that a dose range of 170-180 Gy leads to excellent treatment outcomes with manageable side effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Low-dose rate brachytherapy with I-125 seeds has an excellent 5-year outcome with few side effects in patients with low-risk prostate cancer. Rasmusson, E., Gunnlaugsson, A., Kjellén, E., et al.[2022]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC9953871/

A Contemporary Report of Low-Dose-Rate Brachytherapy ... This study describes the outcomes of 149 men with prostate cancer treated at a single center with Iodine-125 low dose rate brachytherapy ...

2. sciencedirect.com sciencedirect.com/science/article/pii/S2287888223000041

The oncologic and safety outcomes of low-dose-rate ... LDR brachytherapy has several advantages over EBRT such as a higher prescribed dose to the prostate gland while avoiding unnecessary irradiation of organs at ...

3. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC6043740/

Low dose rate prostate brachytherapy - PMC Additionally, LDR brachytherapy often results in biochemical control of 75–95% in patients with intermediate risk disease.

4. clinicaltrials.gov clinicaltrials.gov/study/NCT07210502

Side Effects of Low Dose Rate Brachytherapy and Ultra ... The LDR BURST trial will compare the side effects of two radiotherapy treatments for men with localised prostate cancer.

5. redjournal.org redjournal.org/article/S0360-3016(25)00303-7/abstract

A Randomized Comparison of High-Dose-Rate and Low ... This single-center randomized trial compared health-related Quality of Life for men with unfavorable localized prostate cancer treated with combined pelvic ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10513906/

The oncologic and safety outcomes of low-dose-rate ... LDR brachytherapy has several advantages over EBRT such as a higher prescribed dose to the prostate gland while avoiding unnecessary irradiation of organs at ...

7. sciencedirect.com sciencedirect.com/science/article/abs/pii/S1538472125000017

Safety and early outcomes of proton therapy and low-dose ... At 45 months' follow-up time, treatment with PT and LDR boost led to high control rates and low toxicity for men with prostate cancer.

8. eu-openscience.europeanurology.com eu-openscience.europeanurology.com/article/S2666-1683(24)01426-5/fulltext

Predicting Urinary Function Outcomes Following Low-dose ... We created a tool to predict the likelihood of urinary problems after a type of radiotherapy called brachytherapy for prostate cancer. The size ...