Prospective intra-individual blinded comparison of [¹⁸F]PSMA-1007 and [⁶⁸ Ga]Ga-PSMA-11 PET/CT imaging in patients...

[¹⁸F]PSMA-1007 has potential advantages over [⁶⁸ Ga]Ga-PSMA-11, although limited prospective data evaluating diagnostic performance exist. The aims of this study are to describe the concordance of [¹⁸FPSMA-1007 and [⁶⁸ Ga]Ga-PSMA-11 for TNM with the American Joint Committee on Cancer (AJCC) prognostic stage and assess differences in tracer uptake.

Fifty men (mean age 71.8) were imaged with [⁶⁸ Ga]Ga-PSMA-11 and [¹⁸F]PSMA-1007 < 4 weeks apart. Images were independently reported according to TNM by two experienced nuclear medicine specialists blinded to the other scan and prior imaging. Discordant results were resolved by a third independent nuclear medicine specialist. Quantitative analysis of lesion uptake and physiologic tissue for each tracer was performed by one experienced reader.

Scan indications were initial staging (n = 12), biochemical recurrence (n = 27) and metastatic disease evaluation (n = 11). Most patients had ISUP grade group 3 or higher. Median PSA value was 2.7 ng/ml (IQR 0.7-12.0), and a minority of patients (28%) were currently treated with androgen deprivation therapy. [¹⁸F]PSMA-1007 uptake was significantly higher than [⁶⁸Ga]Ga-PSMA-11 in local recurrence, nodal and distant metastases and most physiologic sites (including bone) except for urinary bladder which was significantly lower. [¹⁸F]PSMA-1007 upstaged local prostate staging in 5/17 patients, local recurrence in 3/33 patients, regional nodal disease in 3/50 patients and 1 distant metastasis (bladder). [⁶⁸Ga]Ga-PSMA-11 upstaged regional nodal disease in 1/50 patients and distant metastasis in one patient (right adrenal). Overall AJCC prognostic stage was concordant in 46/50 (92%) patients, with two patients upstaged for both [¹⁸F]PSMA-1007 and [⁶⁸Ga]Ga-PSMA-11. [¹⁸F]PSMA-1007 had more equivocal results (one regional node; six equivocal bone lesions, one of which was subsequently confirmed metastatic) than [⁶⁸Ga]Ga-PSMA-11 (one equivocal local recurrence).

Overall AJCC prognostic stage was similar (92%) between [¹⁸F]PSMA-1007 and [⁶⁸Ga]Ga-PSMA-11. [¹⁸F]PSMA-1007 demonstrates higher uptake within involved nodes and distant metastases and most physiologic sites except urinary bladder which aided [¹⁸F]PSMA-1007 local staging of the prostate primary/local recurrence and regional nodal disease adjacent ureters. However, [¹⁸F]PSMA-1007 liver uptake obscured a solitary right adrenal metastasis, and more equivocal bone lesions were identified. Trial registration The study was registered with Australia New Zealand Clinical Trials Registry (ACTRN12618000665235) on 24 April 2018.