Magnetic Resonance-Guided High-Dose Brachytherapy (Short-Range Radiation Therapy) for Prostate Cancer
Condition: Prostate Cancer
MeSH terms: Prostatic Neoplasms
Study type: Interventional
Phase: Phase 2

Summary: 
      This study will evaluate the use of magnetic resonance imaging (MRI) for guiding placement of
      hollow needles into the prostate gland for delivering internal radiation therapy to patients
      with prostate cancer. Prostate cancer is often treated with a combination of external beam
      radiation therapy and brachytherapy (internal radiation delivered close to the tumor). This
      study will determine whether MRI is more accurate in guiding needle placement than
      ultrasound, which is currently used for this purpose. Patients will have one brachytherapy
      treatment followed by 5 weeks of external beam treatments and a second brachytherapy.

      Patients 18 years of age and older with prostate cancer that has not spread to the bone may
      be eligible for this study. Candidates will be screened with a physical examination, blood
      and urine tests, and a bone scan.

      To plan for radiation therapy, patients will have standard computed tomography (CT) and MRI
      scans of the pelvis and prostate. In addition, CT and MRI scans will be done to determine if
      the prostate is in a good position for brachytherapy. For these scans, patients will have an
      enema and a tube will be placed in the rectum. They will then lie still on their side for
      about 45 minutes during the scan. Patients who have blood in their urine will also undergo
      cystoscopy. This is an examination of the bladder using a small camera that is advanced
      through the penis into the bladder.

      Patients are given an antibiotic for 2 days before the brachytherapy and on the morning of
      the procedure. Before the test, they have a small enema and are given medicines through the
      vein and into the spine for relaxation and to decrease any discomfort. (The test is done
      under general anesthesia for patients who require it.) The patient is moved on a stretcher
      into the MRI scanner and a catheter is inserted into the bladder through the penis. The
      bladder is filled with water and a tube is placed in the rectum. With the help of a plastic
      guide placed against the skin, about 14 to 18 needles are then placed in the prostate. Some
      stitches are sewn to hold the needles and the guide in place, and the tube in the rectum is
      removed. The patient is the transferred from the MR scanner into the CT scanner, where the
      rectal tube is reinserted and the needles are adjusted. A cystoscopy is done to make sure the
      needles do not enter the bladder. When the needles are adjusted, the tube is removed from the
      rectum and the patient is moved to the radiation oncology clinic.

      After a few hours, when the radiation dose has been calculated, a radioactive substance
      called iridium is administered. The needles placed in the prostate are connected to a
      radiation machine, and thin wires with radioactive material on the tips are inserted into
      each needle and withdrawn a little at a time. The process takes about 20 to 30 minutes. The
      patient is then disconnected from the machine and undergoes another MRI scan to confirm the
      position of the needles. The needles and catheter are then removed and the patient is
      monitored for a while before going home. Patients then have 5 weeks of external beam therapy,
      followed by a second brachytherapy treatment.

      Patients return to the clinic at 1, 3, 6, 12, 18, 24, 36, 48, and 60 months after treatment
      for blood tests, physical examination, and review of symptoms.
    

Detailed description: 
      BACKGROUND

      Brachytherapy, the placement of a radioactive source close to a tumor, is rapidly becoming an
      important modality for patients with prostate cancer because higher and more conformal doses
      can be safely delivered compared with external beam radiotherapy.

      High dose rate (HDR) temporary implants offer several treatment and research based advantages
      over permanent seeds, including exceptionally complex and accurate dosimetry in reference to
      anatomic images.

      Needle placement in brachytherapy procedures requires detailed image guidance, traditionally
      obtained with trans-rectal ultrasound (TRUS). MRI offers a 3D dataset, arbitrary imaging
      planes, and unparalleled soft tissue resolution of the anatomy, making it the modality of
      choice for imaging the prostate gland.

      A real-time MR-guided prostate permanent seed implant technique that utilizes both real-time
      MRI and real-time dosimetry has been designed, implemented and reported. Results confirm that
      TRUS-guided implants may be improved upon by using MRI. To our knowledge, HDR implants have
      not yet been performed under MR guidance in a closed bore magnet.

      OBJECTIVES

      The primary objective is to determine the quality of prostate HDR brachytherapy implants
      performed under MR-guidance.

      Quality is defined by the percentage of the planning target volume (PTV) encompassed by a
      given percentage of the prescribed dose. In this study an implant will be of "acceptable"
      quality if 80% of the PTV is encompassed by the 100% isodose (V100 80%), in accordance with
      RTOG guidelines.

      ELIGIBILITY

      Pathologically confirmed prostate cancer with the following features:

        -  Gleason score greater than 6, or greater than T2a, or

        -  PSA greater than or equal to 10, and no evidence of bone metastases;

      Age greater than or equal to 18 years;

      ECOG performance status of 0 or 1

      DESIGN

      The study is designed with a "run-in" pilot phase with the objective of refining the
      technique.

      The evaluation phase is a two-stage optimal design to evaluate the quality of the implant
      with an early look for futility.

      This study has the potential to enroll a maximum of 27 patients.

      Radiation treatment parameters will be patterned after established guidelines in the
      literature such as those reported by the American Brachytherapy Society and the
      William-Beaumont Hospital. There will be no attempted dose escalation or attempts to
      prescribe the dose to unconventional target volumes in this phase of the project.
    

Intervention name(s): Brachytherapy
Intervention type(s): Radiation
Intervention description(s): Patients will receive two HDR brachytherapy implants (950-1050 cGy/implant) before and at the end of a course of external beam radiotherapy (4600 cGy, 2Gy/day).
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Radiation Therapy; Prostate; MRI; Brachytherapy; Phase II; Prostate Cancer