The US Food and Drug Administration (FDA) has approved the production and use of 11C choline, an agent shown to be effective in detecting recurrent prostate cancer during positron emission tomography (PET) imaging.
PET imaging with 11C choline is performed in patients previously treated for prostate cancer who have elevated prostate-specific antigen (PSA) levels. A rising PSA can signal a recurrence even when computerized tomography (CT) imaging shows no sign of disease.
11C choline “provides an important imaging method to help detect the location of prostate cancer in patients whose blood tests suggest recurrent cancer when other imaging tests are negative,” said Charles Ganley, MD, director of the office of drug evaluation at the FDA, in a press release.
The results of four independent studies led to the approval of 11C choline as an imaging agent. In total, 98 patients with elevated PSA levels, but no sign of prostate cancer recurrence during CT scans, underwent PET imaging with 11C choline. Biopsies were performed on all abnormalities found during the PET scan.
Roughly 50% of patients biopsied within each study were ultimately found to have recurrent prostate cancer. False positives varied by study, ranging from 15% to 47% of patients, confirming the need for biopsies. Other than a mild skin reaction at the site of injection, no side effects were reported.
The Mayo Clinic PET Radiochemistry Facility in Rochester, Minnesota is the first facility approved for manufacturing 11C choline, which must be administered to patients shortly after production.