18F-DCFPyL and 18F-PSMA-JK7 for staging of primary prostate cancer: an interpatient comparison in 500 patients.

Rationale: Staging primary prostate cancer with prostate specific membrane antigen (PSMA) PET/computed tomography is incorporated in recent guidelines, given its pivotal role in guiding therapy selection and prognostication. Little is known about differences in diagnostic performance between different PSMA tracers. In this study the performance of 18F-DCFPyL (PyL) is compared with 18F-PSMA-JK7 (JK7) in primary staging.

Methods: Interpatient comparison of 250 patients scanned with PyL and 250 with JK7. Detection of primary lesions and metastases in locoregional lymph nodes, distant lymph nodes, bone, and other distant metastases as well as clinical outcomes in an operated subcohort were compared. Differences were reported as odds ratios (ORs) and were calculated by means of an univariable and multivariable logistic regression.

Results: No significant differences in detection of metastases between PyL and JK7 were found; locoregional lymph nodes (OR: 0.81, P = 0.34), distant lymph nodes (OR: 1.15, P = 0.60), bone (OR: 0.91, P = 0.72) and other distant metastases (OR: 0.95, P = 0.91). In a subcohort of 68 operated patients the true-negative rate was 86 and 90% and the false-negative rate was 14 and 10% for PyL and JK7 (P = 0.52), respectively.

Conclusion: No clinically relevant differences are found between PyL and JK7 for staging of primary prostate cancer. Both in terms of detection rates of primary tumor and metastases as well as in terms of PET true-negative and false-negative rates in the subcohort treated with surgery. This data indicates that the diagnostic value of JK7 is comparable to PyL.