18F-PSMA-1007 multiparametric, dynamic PET/CT in biochemical relapse and progression of prostate cancer

Abstract

Aim of the present analysis is to investigate the biodistribution and pharmacokinetics of the recently clinically introduced radioligand 18F-PSMA-1007 in patients with biochemical recurrence or progression of prostate cancer (PC) by means of multiparametric (dynamic and whole-body) PET/CT. Twenty-five (25) patients with PC biochemical relapse or progression (median age\u2009=\u200966.0 years) were enrolled in the analysis. The median PSA value was 1.2 ng/mL (range\u2009=\u20090.1–237.3 ng/mL) and the median Gleason score was 7 (range\u2009=\u20096–10). All patients underwent dynamic PET/CT (dPET/CT) scanning (60 min) of the pelvis and lower abdomen as well as whole-body PET/CT with 18F-PSMA-1007. PET/CT assessment was based on qualitative evaluation, SUV calculation, and quantitative analysis based on a two-tissue compartment model and fractal analysis. 15/25 patients were PET-positive. Plasma PSA values in the 18F-PSMA-1007 positive group were higher (median\u2009=\u20093.6 ng/mL; range\u2009=\u20090.2–237.3 ng/mL) than in the 18F-PSMA-1007 negative group (median value\u2009=\u20090.7 ng/mL; range\u2009=\u20090.1–3.0 ng/mL). Semi-quantitative analysis in the PC lesions demonstrated a mean SUVaverage\u2009=\u200925.1 (median\u2009=\u200915.4; range\u2009=\u20093.5–119.2) and a mean SUVmax\u2009=\u200941.5 (median\u2009=\u200925.7; range\u2009=\u20093.8–213.2). Time–activity curves derived from dPET/CT revealed an increasing tracer accumulation during the 60 min of dynamic PET acquisition into the PC lesions, higher than in the urinary bladder and the colon. Significant correlations were observed between 18F-PSMA-1007 uptake (SUV), influx, and fractal dimension (FD). 18F-PSMA-1007 PET/CT could detect PC lesions in 60% of the patients of a mixed population, including also patients with very low PSA values. Higher PSA values were associated with a higher detection rate. Dynamic PET analysis revealed an increasing tracer uptake during the dynamic PET acquisition as well as high binding and internalization of the radiofluorinated PSMA ligand in the PC lesions.