Combination of MRI prostate and 18F‐DCFPyl PSMA PET/CT detects all clinically significant prostate cancers in treatment‐naive patients: An international multicentre retrospective study

INTRODUCTION: Clinical and biochemical assessment and biopsies can miss clinically significant prostate cancers (csPCa) in up to 20% of patients and diagnose clinically insignificant tumours leading to overtreatment. This retrospective study analyses the accuracy of (18)F‐DCFPyL PET/CT in detecting csPCa as a primary diagnostic tool and directly compares it with mpMRI prostate in treatment‐naive patients. The two modalities are then correlated to determine whether they are better in combination, than either alone. METHODS: This is a retrospective dual‐institution study of patients who underwent contemporaneous MRI and PSMA‐PET between January 2017 and March 2020 with histologic confirmation. The images were re‐reviewed and concordance between modalities assessed. Results were compared with histopathology to determine the ability of MRI and PSMA‐PET to detect csPCA. RESULTS: MRI and PSMA‐PET detected the same index lesion in 90.8% of cases with a kappa of 0.82. PET detected an additional 6.2% of index lesions which were MRI occult. MRI detected an additional 3.1% which were PET occult. No additional csPCa was identified on pathology which was not seen on imaging. The sensitivity of PSMA‐PET in detecting csPCa is 96.7% and that of MRI is 93.4% with no statistically significant difference between the two (P = 0.232). Both modalities detected all four cases of non‐csPCa with these being considered false positives. CONCLUSION: Both mpMRI and 18F‐DCFPyL‐PSMA‐PET/CT have high sensitivity for detecting csPCa with high agreement between modalities. There were no synchronous csPCa lesions detected on pathology that were not detected on imaging too.