Evaluation of Gallium-68 PSMA PET/CT imaging in individuals with biochemical recurrence following radical prostatectomy
Prostate specific membrane antigen (PSMA) is a transmembrane protein that is highly expressed in most prostate cancers, thus presenting a unique imaging target for the detection of prostate cancer recurrence. This study aimed to investigate the correlation between prostate specific antigen (PSA) level and positive findings on the Ga-68 PSMA PET/CT (PSMA PET) scan in patients with biochemical recurrence following radical prostatectomy.
We conducted a chart review of our institutional prospective database to identify patients with post-prostatectomy biochemical recurrence who underwent 68Ga-PSMA PET/CT (PSMA PET). We then analysed the probability of a positive scan finding for PSMA avid prostate cancer recurrence to the PSA level.
A total of 391 patients were identified for analysis. The median PSA of all individuals included in the study was 2.05ng/ml. Please refer to table 1 and 2.
The probability of PSMA avid lesions detected on a Ga-68 PSMA PET/CT are correlated to the PSA levels in post-prostatectomy patients with biochemical recurrence. Even at low PSA levels (<0.2ng/ml) there is a 42% probability of detecting a PSMA avid lesion, this increases to greater than 90% when PSA levels are >2.0ng/ml. Further studies are required to investigate how detection of PSMA avid lesions will influence the management of these patients with early disease recurrence.