The FDA has approved c11 choline Injection, a Positron Emission Tomography (PET) imaging agent, for use in men to detect prostate cancer recurrences and to locate specific body sites for follow-up tissue sampling, testing and treatment.

The indicated use for c11 choline injection is men with elevated prostate specific antigen (PSA) levels after earlier primary treatment for prostate cancer. c11 choline should not intended as a replacement for tissue testing and sampling prior to additional treatment.

Based on this approval, the Mayo Clinic PET Radiochemistry Facility is the first and only FDA approved c11 choline PET manufacturing facility in the United States. Since c11 choline has an extremely short half life it must be administered immediately after production. Thus, the only place it can be obtained “on label” is at the Mayo Clinic.

c11 choline Injection provides a new imaging contrast to help detect the location of prostate cancer tumors in survivors whose blood tests suggest recurrent cancer while other imaging tests are negative. Other PET scans have not been successful in detecting prostate cancer recurrences until there are much larger masses of cancer cells. c11 choline scans are more sensitive and should allow much earlier detection of potential recurrent tumors, allowing for earlier treatment.

The FDA decided to approve c11 choline Injection after it reviewed data from a meta-analysis of four independent studies involving a total of 98 men with elevated PSA levels, but without any signs of recurrent prostate cancer on CT scans. Not advertised by the doctors using the new contrast is that false positives were observed in 15% to 47% of study participants who underwent c11 choline Injection PET scans, depending on the study. This little known fact confirms the need to have confirmatory tissue sampling for abnormalities detected on all PET scans.

The only adverse events noted with c11 choline were mild injection site reactions.

Joel T Nowak, M.A., M.S.W.