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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 18F‐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.

Purpose Prostate speci c membrane antigen (PSMA) PET/CT is increasingly used in men with biochemical recurrence post-prostatectomy to detect local recurrence and metastatic disease at low PSA levels. The aim of this study was to assess patterns of disease detection, predictive factors and safety using 18 F-DCFPyL PET/CT versus diagnostic CT in men being considered for salvage radiotherapy with biochemical recurrence post-prostatectomy.Methods We conducted a prospective trial recruiting 100 patients with biochemical failure postprostatectomy (PSA 0.2-2.0ng/mL) in men referred for salvage radiotherapy from August 2018 to July 2020. All patients underwent a PSMA PET/CT using the 18 F-DCFPyL tracer and a diagnostic CT. The detection rates of 18 F-DCFPyL PET/CT vs diagnostic CT were compared and patterns of disease are reported. Clinical patient and tumour characteristics were analysed for predictive utility. Thirty-day postscan safety is reported.Results Of 100 patients recruited, 98 were suitable for analysis with a median PSA of 0.32ng/mL. 18 F-DCFPyL PET/CT was positive or equivocal in 52% compared to 19.6% for diagnostic CT. Local recurrence was detected on 18 F-DCFPyL PET/CT in 29.2%, nodal disease was seen in 29.6% and bony metastases in 7.1%. Both ISUP grade group (p = 0.003) and pre-scan PSA (p = 0.061) were signi cant predictors of 18 F-DCFPyL PET/CT positivity, and logistic regression generated probabilities combining the two showed improved prediction rates. No signi cant safety events were reported post 18 F-DCFPyL administration.Conclusions 18 F-DCFPyL PET/CT increases detection of disease in men with biochemical recurrence post-prostatectomy compared to diagnostic CT. Men being considered for salvage radiotherapy with a PSA > 0.2ng/mL should be considered for 18 F-DCFPyL PET/CT scan.

Tumors induced by foreign bodies are uncommon in humans, but they are a relatively common occurrence in some experimental animals. The development of sarcoma in association with metallic foreign bodies has rarely been reported. The development of a malignant fibrous histiocytoma in a 65-year-old man 44 years after shrapnel fragments lodged in his left arm is described. The literature regarding metallic foreign body-induced cancer in humans is reviewed.