Clinical management intent of Ga68 PSMA PET/CT imaging in prostate cancer: an Australian multicentre study.

Objectives: Ga68-Prostate Specific Membrane Antigen (PSMA) PET/CT is being increasingly used in the assessment of patients with prostate cancer. The aim of this study was to determine its impact in the clinical management of patients with prostate cancer.

Methods: This prospective multicentre study assessed the management intent of patients undergoing Ga68 PSMA PET/CT in 4 Australian centres. Referring medical specialists completed a management intent survey prior to their patients undergoing Ga68 PSMA PET/CT scanning. A follow up survey was then completed by the referring specialist once the results of the Ga68-PSMA PET/CT results were made available. The primary question was to determine whether (and to what degree) their management plan would change based on the PSMA PET/CT scan findings.

Results: For the period between January 2015 and June 2016, 431 patients had pre- and post-Ga68 PSMA management plans completed by their referring specialists. Scans were performed for primary staging in 25% patients and for a rising PSA following surgery and/or radiotherapy in 75% of patients. On the post PSMA survey, the clinicians indicated that the scan led to a change in planned management in 51% of patients. A greater management change was noted for patients with an indication of biochemical recurrence (post-surgery 64%, post radiation therapy 69%), compared with primary staging (23%). Preliminary analysis showed that the PSMA scan detected disease that was not previously suspected in the prostate bed (30% of patients), locoregional lymph nodes (36% of patients) and distant disease (16% of patients).

Conclusion: Ga68 PSMA PET/CT scans detect previously unsuspected disease and change planned clinical management in a high proportion of patients with prostate cancer. The impact was much greater in patients with biochemical recurrence post surgery or radiation therapy, compared with primary staging. Research Support: