To effectively treat prostate cancer, doctors need an accurate view (via X-rays) of the
prostate gland during radiation therapy. To help improve this view, doctors may insert gold
markers called fiducials into the prostate by placing hollow gold needles through the rectum
and moving a fiducial through each needle. The purpose of the study is to determine whether
an MRI scan can help doctors improve their placement of these needles.
Fifteen men will participate in this study. Patients will take the antibiotic levofloxacin
for two days prior to the placement of the fiducials, then will have a small enema and
another dose of the antibiotic on the morning of the procedure. After being anesthetized,
patients will have an antenna-like tube placed into the rectum and have MRI images taken of
the area. The doctor will then use these scans to place four fiducials into the prostate. The
procedure will require approximately 45 minutes. Patients will be allowed to go home the same
day of the procedure, which will be followed by a seven-week course of standard radiation
Prior to their participation in this study, patients will undergo the following evaluations:
a physical exam, blood work, urine tests, and, if appropriate, an MRI or bone scan.
Effective image-guided prostate therapies require excellent visualization of the prostate and
surrounding anatomy, such that cancerous tissue can be treated while avoiding nearby neural
and vascular structures. As such, Magnetic Resonance Imaging is well suited for
image-guidance because of its excellent soft tissue contrast, multiplanar capabilities, and
the potential to yield spectral/biological tumor mapping. Despite the potential for
MRI-guided prostate therapies, there are currently no techniques that allow for precise
trans-rectal intraprostatic needle placement in patients.
In this pilot study we seek to validate the accuracy and tolerability of a new system and
technique that allows for accurate placement of needles within the prostate based upon MR
images. The method is very similar to transrectal ultrasound guided biopsy of the prostate,
except that it is applicable within a closed high-field MRI scanner. Four gold fiducial
markers will be placed within the prostate under needle guidance in a series of patients with
localized prostate cancer before external beam radiotherapy. Fifteen patients will be
enrolled onto this study with sample size determined to obtain reasonably precise estimates
of mean placement accuracy. The accrual period is expected to be less than a year.
While placement of the fiducial markers has no direct therapeutic benefit for the patient,
intraprostatic radiopaque fiducial markers (placed under ultrasound) have shown value in
assessing daily setup errors and off-line organ motion during external beam radiation therapy
for prostate cancer. Therefore, a secondary objective is to gain experience using these
intraprostatic fiducial markers for daily assessment and adjustment of external radiation
beam targeting. These markers can also be utilized to aid in CT-MRI fusion and results in
better target delineation for treatment planning. In this way, prostate cancer patients who
are receiving external-beam radiation therapy may benefit from participation.
- INCLUSION CRITERIA:
- Pathologically confirmed adenocarcinoma of the prostate gland.
- 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).
Patients with contraindication to transrectal needle placement:
- Bleeding disorder;
- PT/PTT greater than 1.5.times the upper limit of normal;
- Platelets less than 50K;
- Artificial heart valve.
Patients with contraindications to MRI:
- Patients weighing greater than 136 kg (weight limit for scanner table);
- Patients with pacemakers, cerebral aneurysm clips, shrapnel injury, or implanted
- Patients with chronic inflammatory bowel disease.
- Patients with distant metastatic disease.
- Patients with a prior history of pelvic or prostate radiotherapy.
- Cognitively impaired patients who cannot give informed consent.
- Other medical conditions deemed by the PI or associates to make the patient ineligible
for protocol investigations, procedures, and high-dose external beam radiotherapy.