Tond Velde Bogsrud, MD PhD, from the Oslo University Hospital in Olso, Norway presented new data at the 2016 Society of Nuclear Medicine and Molecular Imaging annual meeting.
The study was conducted to determine whether FACBC PET can help disease staging prior to selection of definitive primary treatment.
The Oslo University researcher designed a retrospective analysis of 86 biopsy-proved prostate cancer patients of which 55 are high-risk (D’Amico). Patients underwent PET-CT scanning in a single timepoint (3-5 minutes) after an intravenous injection of about 10 mCi of FACBC. The primary disease site, metastases as well as pelvic lymph node involvement were determined from the PET-CT. Standard-of-truth (histology) was available for prostate biopsy in 61/86 patients, for pelvic LN in 55 patients and for distant metastases in 31 patients. PET-evaluation was qualitative and no standardized uptake value (SUV) range or scale was incorporated in the study.
For analysis at the regional level, the Positive Predictive Value (PPV) of FACBC for prostate tumor site determination was 100% and 91.8% detection rate. Detection rate/sensitivity for outside of prostate was 37.3% while the PPV and NPV (Negative Predictive Value) for pelvic LN detection were both 69%. For analysis at the subject level, the PPV was 100% and sensitivity was 93.4%. The authors concluded that FACBC PET-CT is predictive of regional lymph node and distant metastases in high-risk prostate cancer patients.
F-18 FACBC (AXUMIN) has gained approval from the US FDA since May 2016 for the detection of recurrent prostate cancer in patients with elevated PSA. Its use in the detection of primary prostate cancer and metastases, although intuitively favorable, still needs further scrutiny. Furthermore, although reader-training programs to interpret FACBC PET-CT are effective (poster #1556), it will indeed take some time (like months) for imagers to train to widely adapt F-18 FACBC PET for the care of prostate cancer patients.
Upon questioning, the author answered that SUV was not evaluated. The use of standard imaging parameters such as SUV in FACBC PET still needs to be evaluated.
Presented by Tond Velde Bogsrud, MD. PhD, at the 2016 Society of Nuclear Medicine and Molecular Imaging annual meeting in San Diego, CA, USA. Abstract #520.