FDA green-lights PET agent for recurrent prostate cancer detection
PET imaging with Choline C 11 Injection is performed in patients whose blood prostate specific antigen (PSA) levels are increasing after earlier treatment for prostate cancer. An elevated PSA result suggests that prostate cancer may have returned, even though conventional imaging tests, such as CT, have not shown any signs of cancer.
PET imaging is not a replacement for tissue sampling and testing, the FDA said in a press release. Choline C 11 Injection is administered intravenously to produce an image that helps to locate specific body sites for follow-up tissue sampling and testing in men with recurrent prostate cancer.
Choline C 11 Injection must be produced in a specialized facility and administered to patients shortly after its production. While PET imaging with Choline C 11 Injection has been performed at a few facilities over the past several years, none of these facilities were approved by the FDA to manufacture the agent.
The safety and effectiveness of Choline C 11 Injection were verified by a systematic review of published study reports. Four independent studies examined a total of 98 patients with elevated blood PSA levels but no sign of recurrent prostate cancer on conventional imaging. After PET imaging with Choline C 11, the patients underwent tissue sampling of the abnormalities detected on the PET scans.
In each of the four studies, at least half the patients who had abnormalities detected on PET scans also had recurrent prostate cancer confirmed by tissue sampling of the abnormal areas. PET scan errors also were reported. Depending on the study, false-positive PET scans were observed in 15 percent to 47 percent of the patients. These findings underscore the need for confirmatory tissue sampling of abnormalities detected with Choline C 11 Injection PET scans, according to the FDA.
The Mayo Clinic PET Radiochemistry Facility in Rochester, Minn., is the first FDA-approved facility to produce Choline C 11 Injection.
For more about prostate cancer, look for "Prostate Cancer: In the Eye of the Storm," in the September/October issue of Health Imaging.