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.
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
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.
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
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
The study is designed with a "run-in" pilot phase with the objective of refining the
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.
- INCLUSION CRITERIA:
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
Age greater than or equal to 18 years
ECOG performance status of 0 or 1
Informed consent: All patients must sign a document of informed consent indicating their
understanding of the investigational nature and risks of the study before any protocol
related studies are performed (this does not include routine laboratory tests or imaging
studies required to establish eligibility).
History of prior pelvic or prostate radiotherapy
TURP within the last 6 months or large TURP defect
Contraindication to implant procedure:
- Bleeding disorder
- Active anticoagulation at the time of implant
- Artificial heart valve
Contraindication to MRI:
- Patients weighing greater than 136 kgs (weight limit for the scanner tables)
- Patients with pacemakers, cerebral aneurysm clips, shrapnel injury or implantable
Preexisting significant urinary obstructive symptoms as reflected by a high (greater than
18) International Prostate Symptom Score (IPSS)
Pubic arch interference or inadequate access to perineum as determined by preliminary MRI
Cognitively impaired patients who cannot give informed consent
Medically Unfit for Anesthesia as defined by an anesthesiology consultant
Other active malignancy (except for non-melanoma skin cancer or malignancy which was
treated with curative intent at least 3 years ago with no further evidence of recurrent
Other urinary or medical conditions deemed by the PI or associates to make the patient
ineligible for high dose rate brachytherapy and EBRT.