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

60 Participants Needed

Trial Summary

What is the purpose of this trial?

Radiation therapy plays an important role in the management of prostate cancer. In recent years it has become evident that higher doses of radiation are required to optimize disease control. The limiting factor of escalating dose to the prostate is the surrounding normal tissue. Despite advances in escalating radiation therapy, failures still occur in 20-30% of patients most often at the site of the original primary disease. As such there is growing interest in further dose escalating to the area of primary disease burden.The aim of this work is to look at the feasibility and toxicities of an integrated focal boost to whole gland prostate treatment using high dose rate brachytherapy.

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 data supports the effectiveness of the treatment MRI Assisted Focal Boost with HDR Monotherapy for prostate cancer?

Research shows that using MRI to guide high-dose-rate brachytherapy (a type of internal radiation) is feasible for targeting prostate cancer, which suggests it could effectively focus treatment on cancerous areas while sparing healthy tissue. ^{1 2 3 4 5}

Is MRI-guided radiation therapy for prostate cancer safe?

Research shows that MRI-guided radiation therapy for prostate cancer, including methods like focal boost and HDR monotherapy, has been studied for safety. A phase 2 trial reported on the treatment's toxicity (side effects) and quality of life, indicating that it is generally safe for humans, though some side effects may occur. ^{1 3 6 7 8}

How is MRI-Guided Radiation Therapy for Prostate Cancer different from other treatments?

This treatment is unique because it uses MRI (magnetic resonance imaging) to guide high-dose-rate brachytherapy (a type of internal radiation) with a focal boost, allowing for precise targeting of cancerous areas in the prostate, potentially improving effectiveness while minimizing damage to surrounding healthy tissue. ^{1 3 8 9 10}

Research Team

Andrew Loblaw, MD

Principal Investigator

Sunnybrook Health Sciences Centre

Eligibility Criteria

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

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

Treatment Details

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.

Participant Groups

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+

Findings from Research

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]

References

1. United States pubmed.ncbi.nlm.nih.gov

IMRT boost dose planning on dominant intraprostatic lesions: gold marker-based three-dimensional fusion of CT with dynamic contrast-enhanced and 1H-spectroscopic MRI. [2019]

2. England pubmed.ncbi.nlm.nih.gov

The influence of MRI scan position on image registration accuracy, target delineation and calculated dose in prostatic radiotherapy. [2021]

3. Ireland pubmed.ncbi.nlm.nih.gov

Dosimetric feasibility of ablative dose escalated focal monotherapy with MRI-guided high-dose-rate (HDR) brachytherapy for prostate cancer. [2018]

4. France pubmed.ncbi.nlm.nih.gov

[Magnetic resonance imaging for delineation of prostate in radiotherapy: monocentric experience and review of literature]. [2012]

5. United States pubmed.ncbi.nlm.nih.gov

MR imaging-controlled transurethral ultrasound therapy for conformal treatment of prostate tissue: initial feasibility in humans. [2012]

6. United States pubmed.ncbi.nlm.nih.gov

Toxicity and Patient-Reported Quality-of-Life Outcomes After Prostate Stereotactic Body Radiation Therapy With Focal Boost to Magnetic Resonance Imaging-Identified Prostate Cancer Lesions: Results of a Phase 2 Trial. [2023]

7. England pubmed.ncbi.nlm.nih.gov

MRI-guided focal boost to dominant intraprostatic lesion using volumetric modulated arc therapy in prostate cancer. Results of a phase II trial. [2023]

8. Ireland pubmed.ncbi.nlm.nih.gov

MRI assisted focal boost integrated with HDR monotherapy study in low and intermediate risk prostate cancer (MARS): Results from a phase II clinical trial. [2020]

9. Netherlands 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. [2022]

10. United States pubmed.ncbi.nlm.nih.gov

MRI simulation: effect of gradient distortions on three-dimensional prostate cancer plans. [2019]