Positron Emission Tomography and Magnetic Resonance Imaging for Prostate Cancer

A Pilot Study of 11C-Acetate Positron Emission Tomography (PET) and 3 Telsa Magnetic Resonance Imaging (MRI) in Men With Prostate Cancer Undergoing Prostatectomy

Background:

• Prostate cancers are difficult to see on most imaging studies such as X-rays, computed tomography (CT) scans, conventional magnetic resonance imaging (MRI) scans and conventional positron emission tomography (PET) scans.
• An experimental radioactive tracer called 11C-acetate accumulates in prostate tumor cells and may help find prostate cancers more accurately than other imaging methods.

Objectives:

• To determine the accuracy of prostate tumor imaging using the tracer 11C-acetate.

Eligibility:

• Patients 18 years of age and older who are undergoing surgery for localized prostate cancer at the National Institutes of Health (NIH) Clinical Center.

Design:

• Patients have a positron emission tomography (PET scan). For this test, an intravenous (IV) line is placed in the patient's arm and the patient lies on a table inside the donut shaped scanner. (11)C-acetate is injected into the vein through the catheter and images of the lower pelvis and abdomen are obtained over 30 minutes.
• Patients have an endorectal coil MRI scan. For this test, a tube is placed in the rectum, just behind the prostate, to increase the amount of signal received by the magnetic resonance (MR) unit. Other coils may be wrapped around the pelvis to further improve the quality of the scan. The patient lies on the scanning table for about 75 to 90 minutes while images are obtained. During the scan, a contrast agent called gadolinium is injected through an intravenous (IV) line to brighten the images.

Background:

• Accurate localization of prostate cancer (PC) is important in developing targeted minimally invasive therapies. While T2 weighted imaging, dynamic contrast enhanced (DCE) imaging, diffusion weighted imaging (DWI), and magnetic resonance (MR) spectroscopy imaging performed at 3T is a useful technique for localizing prostate cancer, it has limitations both in sensitivity and specificity.
• Positron emission tomography (PET) radiopharmaceuticals are more sensitive than magnetic resonance imaging (MRI) for the detection of cancers; however, the resolution of PET is inferior to MRI. Therefore, a combined PET/MR approach might be desirable.
• We propose to evaluate the utility of a PET radiopharmaceutical, (11C) acetate ((11C)AC) for the detection of PC within the prostate and compare its distribution with T2 weighted imaging, dynamic contrast enhanced (DCE) imaging, diffusion weighted imaging (DWI), and MR spectroscopy imaging preformed at 3T.
• Unlike fludeoxyglucose F18(18F)FDG, a routinely used PET radiopharmaceutical which is excreted by the urinary system and accumulates in the bladder, limiting its utility in pelvic imaging, (11C)AC has low physiologic distribution in the pelvis. Several studies involving small numbers of patients have demonstrated that (11C)AC PET imaging can localize in pelvic nodes involved with prostate cancer (PC).
• Dynamic (11C)AC PET/CT examination will be performed in patients with biopsy proven prostate cancer (estimated enrollment 40) who will also undergo prostate/pelvic 3T endorectal coil MR/magnetic resonance spectroscopic imaging (MRSI) followed by surgical resection (+/- pelvic lymphadenectomy).
• Histological comparison with the PET/CT and MRI results will be conducted. This study of (11C)AC in PC will permit the direct comparison of MR/MRSI and (11C)AC PET/CT in the detection of prostate cancer within the prostate.

Objectives:

Primary Objective:

- To compare the biodistribution of (11C) acetate ((11C)AC) PET/CT imaging in tumor and non-tumorous regions of the prostate in patients with known prostate cancer.

Secondary Objective:

• To examine the diagnostic accuracy of the standardized uptake value (SUV) of (11C)AC obtained using PET/CT imaging for detecting region (sextant)-specific malignancy using receiver operating curves (ROC).
• To examine whether pelvic biodistribution of (11C)AC PET/CT imaging predicts sextant-specific malignancy better than T2 weighted imaging, dynamic contrast enhanced (DCE) imaging, diffusion weighted imaging (DWI), and MR spectroscopy (MRS) imaging performed at 3T.
• To evaluate for potential physiological effects of (11C)AC
• To correlate the intensity of (11C)AC uptake with histopathologic Gleason Grade
• Tabulate the incidence of extraprostatic lesions accumulating(11C)AC PET/CT detection which are suspicious for extraprostatic disease by comparing suspicious lesions on (11C)AC PET/CT with standard of care diagnostic imaging modalities, additional biopsy results, or clinical follow-up performed at the discretion of the referring physician.

Eligibility:

• Participants must be scheduled to undergo standard of care prostatectomy for presumed localized prostate cancer at the National Institutes of Health (NIH) Clinical Center.
• Recent (within 12 months of study entry) biopsy indicating the presence of adenocarcinoma of the prostate gland
• Participant must be 18 years or older
• Serum creatinine within 1 week prior to MR imaging less than or equal to 1.8mg/dl AND epidermal growth factor receptor (eGFR) must be greater than 30 ml/min/1.73m^2
• Eastern Cooperative Oncology Group (ECOG) Performance score of 0 or 1
• Participants may not have received androgen deprivation therapy or pelvic radiation therapy

Design:

• Participants with prostate cancer scheduled for prostatectomy at the NIH Clinical Center will undergo 30-minute dynamic (11C)AC PET/CT imaging, and endorectal coil/pelvic T2 weighted, DCE, DWI, and MRS imaging performed at 3T.
• We will accrue 40 participants to this study.

• INCLUSION CRITERIA:
• Participant must be scheduled to undergo standard of care prostatectomy for presumed localized prostate cancer at the National Institutes of Health (NIH) Clinical Center.
• Recent (within 12 months of study entry) trans-rectal biopsy indicating the presence of adenocarcinoma of the prostate gland in which at least sextant biopsies were obtained. Knowledge of the location of each specimen is required for inclusion.
• Participant must be 18 years or older.
• Serum creatinine within 1 week prior to magnetic resonance (MR) imaging less than or equal to 1.8mg/dl AND epidermal growth factor receptor (eGFR) must be greater than 30 ml/min/1.73 m^2
• Eastern Cooperative Oncology Group (ECOG) Performance score of 0 or 1.
• Ability to provide 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.

EXCLUSION CRITERIA:

• Known allergy to gadolinium or acetate.
• Participants for whom participating would significantly delay the scheduled standard of care therapy.
• Participants with any coexisting medical or psychiatric condition that is likely to interfere with study procedures and/or results are excluded.
• Participants with severe claustrophobia.
• Patients with contraindications to magnetic resonance imaging (MRI)
• Patients weighing greater than 136 kg (weight limit for scanner table).
• Patients with pacemakers, cerebral aneurysm clips, shrapnel injury, or other implanted electronic devices or metal not compatible with MRI.
• Patients with contraindication to endorectal coil placement
• Severe hemorrhoids.
• Surgically absent rectum.
• Other medical conditions deemed by the principal investigator (PI) or associates to make the patient ineligible for protocol procedures.
• Patients who have previously received radiation therapy to the pelvis.
• Patients who have received androgen deprivation therapy.