Positron emission tomography (PET) imaging using (68)Ga-PSMA-HBED-CC, also known as (68)Ga-DKFZ-PSMA-11, has emerged as a significant advancement in the diagnostic landscape of recurrent prostate cancer (PCa). Often referred to in practice as a crucial tool in Diagnosis Cc for PCa recurrence, this method has shown considerable promise. However, much of the existing research is based on smaller patient groups. This article delves into a comprehensive study evaluating the diagnostic efficacy of (68)Ga-PSMA-ligand PET/CT in a large patient cohort, examining the influence of various factors on its performance.
A retrospective analysis was conducted on 319 patients who underwent (68)Ga-PSMA-ligand PET/CT between 2011 and 2014. The study meticulously assessed the potential impact of variables such as prostate-specific antigen (PSA) levels, PSA doubling time (DT), Gleason score (GSC), androgen deprivation therapy (ADT) status, patient age, and the quantity of injected tracer. To validate the imaging findings, histological verification was performed in 42 patients following their (68)Ga-PSMA-ligand PET/CT scans. Furthermore, tracer uptake was quantified in 901 representative tumor lesions to provide a detailed lesion-based analysis.
The findings revealed that (68)Ga-PSMA-ligand PET/CT successfully detected at least one lesion indicative of PCa in a significant 82.8% of the patients. Tumor detection rates showed a positive correlation with PSA levels and ADT, suggesting enhanced detection in patients with higher PSA and those undergoing hormone therapy. Interestingly, GSC and PSA-DT did not demonstrate a significant association with tumor detection in this study. The average maximum standardized uptake value (SUVmax) across all tumor lesions was 13.3 ± 14.6, with a range from 0.7 to 122.5, highlighting the variability in tracer uptake.
Among the lesions examined histologically, a small subset of 30 lesions in 4 patients were identified as false-negatives. However, the vast majority of lesions (n = 416) were confirmed as true-positives or true-negatives, underscoring the high accuracy of the imaging technique. Lesion-based analysis demonstrated a sensitivity of 76.6%, a specificity of 100%, a negative predictive value (NPV) of 91.4%, and a positive predictive value (PPV) of 100%. Patient-based analysis further supported these findings, revealing a sensitivity of 88.1%. In a follow-up of 116 patients, 50 received local therapy subsequent to their (68)Ga-PSMA-ligand PET/CT results, indicating the direct clinical impact of this diagnostic modality.
In conclusion, this large-scale evaluation affirms that (68)Ga-PSMA-ligand PET/CT is a highly effective tool for detecting recurrent prostate cancer in a substantial proportion of patients. The radiotracer exhibits remarkable specificity for PCa, minimizing false positives. The positive correlation between tumor detection and PSA levels and ADT provides valuable insights for patient selection and interpretation of results. The study underscores the potential of (68)Ga-PSMA-ligand PET/CT to guide clinical decision-making, potentially enabling the delay of systemic therapy in select PCa patients through improved diagnosis cc and targeted treatment strategies.
