68 Ga‐prostate‐specific membrane antigen (PSMA) PET/CT as a clinical decision‐making tool in biochemically recurrent prostate cancer

Objective PSMA PET/CT has demonstrated superior sensitivity over conventional imaging in the detection of local and distant recurrence in biochemically relapsed (BCR) prostate cancer. We prospectively investigated the management impact of 68 Ga-PSMA PET/CT imaging in men with BCR, with the aim of identifying baseline clinicopathological predictors for management change. Patients and methods Men with BCR who met eligibility criteria underwent 68 Ga-PSMA-11 PET/CT at Monash Health (Melbourne, Australia). Intended management plans were prospectively documented before and after 68 Ga-PSMA PET/CT imaging. Binary logistic regression analysis was performed to identify potential clinicopathological predictors of management change. Descriptive statistics were used to characterize the nature of these changes. Results Seventy men underwent 68 Ga-PSMA-11 PET/CT imaging. Median age was 67 years (IQR 63-72) and median PSA was 0.48 ng/ml (IQR 0.21-1.9). PSMA-avid disease was observed in 56% (39/70) of patients. Pre-scan management plan was altered following scanning in 43% (30/70) of patients. Management changes were significantly more common in patients with higher baseline PSA levels (PSA≥2 ng/ml, p = 0.01). 18/36 (50%) of the patients initially planned for watchful waiting had their management changed, including the use of salvage pelvic radiotherapy (n = 7) and stereotactic ablative body radiotherapy to oligometastatic disease (n = 6). Conclusion Management change after 68 Ga-PSMA PET/CT for BCR is common and typically resulted in treatment intensification strategies in those planned for a watchful waiting approach. This study adds to the growing pool of evidence supporting the clinical utility of PSMA PET/CT imaging in the care of patients with BCR after definitive therapy.