MRI-Guided Radiation Therapy for Prostate Cancer

(MARS Trial)

Age: 18+

Sex: Male

Trial Phase: Academic

Sponsor: Sunnybrook Health Sciences Centre

Must not be taking: Androgen deprivation therapy

Disqualifiers: Metastases, Previous radiotherapy, Poor urinary function, others

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

Compensation: Varies

Number of Visits: Unknown

Duration: 1 day

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 MRI technology to guide higher doses of radiation to the main cancer area. The aim is to determine if this method, called MRI Assisted Focal Boost with HDR Monotherapy (a type of radiation therapy), can target the tumor more effectively while minimizing harm to nearby healthy tissue. It is specifically for men diagnosed with certain types of prostate cancer who can undergo MRI scans and have a specific type of tumor visible on the MRI. Participants should not have had previous pelvic radiation or prostate surgery. As an unphased trial, this study offers a unique opportunity to contribute to innovative research that could lead to more precise and less harmful treatment options for prostate cancer.

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 not allow the use of androgen deprivation therapy. However, 5-alpha-reductase inhibitors are permitted.

What prior data suggests that this MRI-guided radiation therapy is safe for prostate cancer treatment?

Research has shown that using MRI to guide a focused boost of high-dose radiation therapy for prostate cancer is generally safe and well-tolerated. Studies have found that even with higher doses of radiation, patients did not experience severe side effects. Importantly, no serious bowel or urinary problems occurred, which are common concerns with radiation treatments. This method targets higher radiation doses directly at the cancer while protecting the surrounding healthy tissue. The goal is to better control the disease without adding significant risk. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about MRI-Guided Radiation Therapy for prostate cancer because it offers a more precise and targeted approach than traditional methods like external beam radiation or surgery. This treatment uses MRI technology to deliver high-dose-rate (HDR) radiation directly to the prostate gland and provides an additional focal boost to any intraprostatic nodules. This precision aims to maximize the destruction of cancer cells while sparing healthy tissue, potentially reducing side effects and improving patient outcomes. Moreover, the use of a single high-dose treatment (19Gy/1) could offer a more convenient and less time-consuming treatment option compared to the multiple sessions required with standard therapies.

What evidence suggests that MRI-assisted HDR monotherapy is effective for prostate cancer?

Research has shown that MRI-guided radiation therapy with a focused boost to the prostate may be promising for treating prostate cancer. Previous studies combined this method with high dose rate (HDR) monotherapy, which patients have tolerated well. However, while promising, it did not always significantly improve local cancer control. Early trials found that this treatment led to low side effects. Participants in this trial will receive MRI-assisted HDR monotherapy, which previous studies have shown to achieve a 36-month biochemical control rate of 54.4%, helping track cancer activity. This suggests potential benefits, but effectiveness can vary. ^{2 6 7 8 9}

Who Is on the Research Team?

Andrew Loblaw, MD

Principal Investigator

Sunnybrook Health Sciences Centre

Are You a Good Fit for This Trial?

This trial is for men with low to intermediate risk prostate cancer, characterized by specific clinical features (T1-T2c, Gleason score <7, PSA <20 ng/ml), a prostate size less than 60 cc, and no distant metastases. Participants must be able to undergo MRI scans and have not had certain previous treatments or conditions that would exclude them from MR imaging or radiotherapy.

Inclusion Criteria

Ability to undergo MR imaging

Identified MR nodule (PIRADs 4/5)

My prostate cancer diagnosis was confirmed through a tissue examination.

Exclusion Criteria

I have a health condition that makes general anesthesia risky for me.

I have had radiation therapy to my pelvic area before.

I have had surgery or HIFU treatment for prostate issues before.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive HDR monotherapy to the whole prostate gland with MRI assisted focal boost to intraprostatic nodule

1 day

Follow-up

Participants are monitored for acute GU and GI toxicities and quality of life changes

3 months for acute toxicities, 5 years for late toxicities and quality of life

What Are the Treatments Tested in This Trial?

Interventions

• MRI Assisted Focal Boost with HDR Monotherapy

Trial Overview The study is testing the safety and effectiveness of using high dose rate brachytherapy with an MRI-assisted focal boost on the whole gland in treating prostate cancer. The goal is to see if targeting higher radiation doses directly at the primary disease area can improve outcomes without increasing harm to surrounding tissues.

How Is the Trial Designed?

Group I: MRI assisted HDR monotherapy Experimental Treatment 1 Intervention

HDR monotherapy to the whole prostate gland (19Gy/1) with MRI assisted focal boost to intraprostatic nodule up to 22.5Gy

Who Is Running the Clinical Trial?

Sunnybrook Health Sciences Centre

Lead Sponsor

Trials

693

Recruited

1,569,000+

Published Research Related to This Trial

A planning study involving 30 patients suggests that delivering a single 19 Gy dose to recurrent prostate cancer lesions using a 1.5 Tesla MR-Linac system is feasible, with target dose coverage achieved in 57% of MR-Linac plans compared to 47% for traditional FS-HDR-BT.

The MR-Linac system showed comparable effectiveness in dose coverage while potentially reducing exposure to surrounding organs at risk, indicating it could be a safer alternative to invasive FS-HDR-BT for some patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Focal salvage treatment for radiorecurrent prostate cancer: A magnetic resonance-guided stereotactic body radiotherapy versus high-dose-rate brachytherapy planning study. Willigenburg, T., Beld, E., Hes, J., et al.[2022]

Citations

1. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/31564554/

MRI assisted focal boost integrated with HDR monotherapy ... Conclusions: Focal boost to the MRI-specified gross tumor was well tolerated, but did not adequately improve local control. Single-fraction HDR monotherapy to ...

2. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0167814019330956

MRI assisted focal boost integrated with HDR monotherapy ... We report the results of a phase II prospective trial of single-fraction 19 Gy HDR monotherapy with MRI-guided simultaneous focal boost.

3. brachyjournal.com brachyjournal.com/article/S1538-4721(17)30281-7/fulltext

Early Outcomes in a Prospective Phase I/II Trial of MRI ... A total of 37 patients have undergone HDR monotherapy treatment with an integrated DIL boost with a median follow up of 9 months. The median age was 69 years ( ...

4. ascopubs.org ascopubs.org/doi/10.1200/JCO.2017.35.6_suppl.120

Early toxicity in a prospective phase I/II trial of MRI-assisted ... Early toxicity in a prospective phase I/II trial of MRI-assisted focal boost integrated with HDR monotherapy for low- and intermediate-risk prostate cancer.

5. sciencedirect.com sciencedirect.com/science/article/pii/S0167814025045955

Updated results of MR-assisted focal salvage HDR ... Our updated analysis of 59 patients undergoing focal salvage HDR brachytherapy showed a 36-month biochemical control rate of 54.4 % with encouragingly low ...

6. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/32918971/

Single-fraction HDR brachytherapy as monotherapy in low ... Conclusions: MRI-guided focal boost was safe and well tolerated, but did not improve local control after 19 Gy single-fraction HDR monotherapy, ...

7. thegreenjournal.com thegreenjournal.com/article/S0167-8140(24)00651-0/fulltext

Prostate high dose-rate brachytherapy as monotherapy for ... We report on the efficacy of a randomized Phase II trial comparing HDR monotherapy delivered as 27 Gy in 2 fractions vs. 19 Gy in 1 fraction with a median ...

8. mdpi.com mdpi.com/2072-6694/15/19/4888

Focal Boost in Prostate Cancer Radiotherapy: A Review of ... MRI assisted focal boost integrated with HDR monotherapy study in low and intermediate risk prostate cancer (MARS): Results from a phase II clinical trial.

9. aapm.onlinelibrary.wiley.com aapm.onlinelibrary.wiley.com/doi/10.1002/mp.15713

AAPM task group report 303 endorsed by the ABS: MRI ... MRI assisted focal boost integrated with HDR monotherapy study in low and intermediate risk prostate cancer patients (MARS) (NCT02623933) ...