Diagnostic performance of positron emission tomography combined with computed tomography with 18F-PSMA-1007 for detecting local recurrence of prostate cancer after radical prostatectomy

Abstract

In the situation of biochemical recurrence (BCR) of prostate cancer (PCa) it is important to distinguish between local recurrence in the prostate bed and systemic disease progression. Conventional imaging modalities have a limited role, especially in patients with low prostate specific antigen (PSA) levels. In recent years, the role of positron emission tomography combined with computed tomography (PET/CT) with PSMA-labeled ligands has grown, but there is currently no consensus on the role and effectiveness of the method in detecting local recurrence of the disease. The aim of the study was to analyze the diagnostic performance of 18F-PSMA‐1007 PET/CT in detecting local recurrence of prostate cancer. The study included 57 patients with BCR after radical prostatectomy, who underwent PET/CT with 18F-PSMA-1007 and according to its results there were no distant and/or regional metastases. Local recurrence was clinically verified in 53 (93.0%) patients. The sensitivity of PET/CT in detecting local recurrence was 58.5 %, specificity ‒ 75.0, positive predictive value ‒ 96.9, negative predictive value ‒ 12.0 %. According to multivariate analysis, only PSA level was significantly associated with truepositive PET/CT findings (p = 0.02). According to multivariate analysis, PSA level is an independent predictive factor of 18F-PSMA‐1007 PET/CT sensitivity in detecting local recurrence (p < 0.05). In the subgroup of patients with a low PSA level sensitivity was only 20.0 %. Therefore, a negative PET/CT scan at PSA level <0.5 ng/ml is not a reason for delay the initiation of salvage radiation therapy.