Magnetic Resonance (MR) Linear Accelerator (linac) prostate radiotherapy trial

A clinical trial exploring MR guided adaptive stereotactic radiotherapy boost to the prostate combined with stereotactic radiotherapy to the whole pelvis

Status

Not yet recruiting

Phases

Phase 2

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12623000919617

Acronym

MR-PROTEUS

Enrollment

Registered

2023-08-28

Start date

2023-10-01

Completion date

2026-10-01

Last updated

2023-09-04

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

This study aims to assess where a type of radiotherapy technique called stereotactic body radiotherapy (SBRT) can be delivered using a machine called a linear accelerator which uses magnetic resonance (MR) images and is safe for patients. The machine is also known as an MR-linac, and is a newer type of linear accelerator which is available in Australia. Standard linear accelerators use Computed Tomography (CT) images to guide treatment. MR images create better quality images of the body and can therefore better guide radiotherapy treatment. The SBRT technique for delivering radiotherapy has been used on standard linear accelerators to treat both the prostate and pelvis, as well as on the MR-linac to treat the prostate. However this study is the first time that SBRT for both the prostate and pelvis will be tested on the MR-linac. Who is it for? You may be eligible for this study if you are an adult older than 18 years of age, you have been diagnosed with a localised intermediate or high risk prostate cancer and you are planned to undergo radiotherapy treatment for your cancer. If you are unable to have an MRI for any reason e.g. pacemaker, claustrophobia etc. then you will not be able to take part. Study details Participants who choose to enrol in this study will receive SBRT on the MR-linac to their prostate and pelvis. They will be randomly allocated to receive one of the two treatment protocols available in the study. They are: Arm 1: SBRT to the prostate given in two treatments, followed by the pelvis in five treatments. Treatments will be once per week. Arm 2: SBRT to the prostate given in one treatment, followed by the pelvis in five treatments and then one last treatment to the prostate. Participants will be followed up regularly for a total of 3 years after they complete the study radiotherapy. During this time, treatment related side effects and prostate specific antigen (PSA) outcomes will be tracked, as well as patient reported outcomes or quality of life. It is hoped this research will determine whether SBRT to both the prostate and pelvis delivered using the MR-linac is feasible and safe for patients. This will help to design better radiotherapy treatment options for prostate cancer patients in the future.

Interventions

Stereotactic pelvic radiotherapy combined with dose escalation to the prostate via a Stereotactic Body Radiotherapy (SBRT) boost will be delivered using an magnetic resonance (MR) Linear Accelerator (Linac). Participants will be randomised to receive either: Arm 1: Prostate SBRT: 10Gy per fraction in 2 treatments, 1 fraction per week (a minimum of 7 and a maximum of 11 days apart) delivered before pelvic SBRT. Pelvic SBRT: 25Gy in 5 fractions (5Gy per fraction), 1 fraction per week over 5 weeks. Should commence between 7 to 11days after the second SBRT fraction. Arm 2: Prostate SBRT: 10Gy per fraction in 1 treatment 7 to 11 days before pelvic SBRT and 10Gy per fraction in 1 treatment 7 to 11 days after pelvic SBRT. Pelvic SBRT: 25Gy in 5 fractions (5Gy per fraction) treated weekly over 5 weeks. Should commence between 7 to 11 days after the first SBRT fraction. Trial radiotherapy will be delivered by radiation therapists under the direction of the treating radiation oncologist according to the research protocol and standard clinical operating procedures of the clinic. Each SBRT treatment will take approximately 40 minutes.

Study design

Allocation

Randomised controlled trial

Intervention model

Parallel

Primary purpose

Treatment

Masking

Open (masking not used)

Eligibility

Sex/Gender

Male

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

1. Patient capable of giving informed consent 2. Histological diagnosis of prostate cancer 3. Intermediate or High-risk disease respectively defined by any one of: a. Baseline Prostate Specific Antigen (PSA) 10-20, Gleason grade 7 disease, Clinical stage T2b-c OR b. Baseline PSA equal to or more than 20, Gleason grade 8-10 disease, Clinical stage T3 4. For high-risk patients, conventional staging (in the form of any of the below) negative for extra pelvic disease: a. PSMA PET scan OR b. Tc99m whole body bone scan AND c. Either CT of the abdomen and pelvis or MRI pelvis 5. No previous pelvic radiotherapy

Exclusion criteria

1. ECOG performance status more than 1 2. Inability to have an MRI due to: a. Implanted magnetic metal eg intraocular metal b. Pacemaker or Implantable defibrillator c. Extreme claustrophobia 3. Clinical stage T4 (tumour invasion into adjacent anatomical structures) 4. Inflammatory bowel disease 5. Severe obstructive urinary symptoms 6. Inability to meet planning objectives 7. Severe Claustrophobia 8. Contraindication to MRI

Outcome results