68 Ga-PSMA PET/CT tumour intensity pre-operatively predicts adverse pathological outcomes and progression-free survival in localised prostate cancer

PURPOSE Prostate-specific membrane antigen (PSMA) positron emission tomography (PSMA-PET) improves prostate cancer staging. Intraprostatic PSMA intensity may predict clinically relevant oncological outcomes. The aim of this study was to investigate the relationship between intraprostatic PSMA intensity and adverse pathology outcomes, including biochemical progression-free survival (PFS) after radical prostatectomy. METHODS This is a cohort study of 71 patients with MRI-guided, biopsy-proven prostate cancer and pre-operative 68Ga-PSMA-11 PET/CT prior to radical prostatectomy (RP). Intraprostatic PSMA intensity was correlated to adverse pathology outcomes (Gleason score and upgrading from biopsy, pathological stage) and PFS using multivariate statistical analysis. RESULTS 68Ga-PSMA-11 PET/CT intensity in vivo predicted all of Gleason score on RP, upgrading from biopsy to RP histopathology, pathological stage, positive surgical margins and PFS. 74.6% (53/71) of patients were free from progression at a median follow-up of 19.5 months (0.4-48 months). Predictive accuracy was particularly enhanced by PSMA among patients with biopsy Gleason score ≤ 3 + 4 (n = 39) as the most significant predictor of PFS according to Cox-proportional hazards regression. Cox-regression adjusted survival analysis predicted a 5.48-fold increase in hazard for Gleason score ≤ 3 + 4 patients with high (SUVmax > 8) compared with low (SUVmax < 8) PSMA intensity. CONCLUSION Intraprostatic 68Ga-PSMA-11 intensity is prognostic and may be a valuable new biomarker in localised prostate cancer, especially in men with biopsy-proven Gleason 3 + 4 disease considering an initial approach of active surveillance or focal therapy.