Correlation of PSA blood levels with standard uptake value maximum (SUV max ) and total metabolic tumor volume (TMTV) in 18F-PSMA-1007 and 18F-choline PET/CT in patients with biochemically recurrent prostate cancer.

Objectives: In this prospective study, we investigated the correlation between prostate-specific antigen (PSA) levels in the blood of patients with prostate cancer in biochemical recurrence after radical treatment with the semiquantitative parameters standard uptake value maximum (SUV max ) and the total metabolic tumor volume (TMTV) in the metastatic foci depicted in 18F-prostate-specific membrane antigen (PSMA)-1007 and 18F-choline PET/computed tomography (CT) imaging.

Methods: We prospectively examined 104 patients with biochemical relapse of prostate cancer after primary definitive treatment. All patients underwent one 18F-PSMA-1007 and one 18F-choline PET/CT examination in randomized order within a time frame of 10 days and were followed for at least 6 months (182 ± 10 days). The semiquantitative parameters of SUV max and metabolic tumor volume (MTV) of each neoplastic lesion in PET/CT imaging were calculated, and further summation of each MTV value was done to calculate the TMTV.

Results: According to the Spearman correlation analysis, a positive correlation was found between PSA levels and SUV max and TMTV scores in the metastatic foci of 18F-PSMA-1007 PET/CT ( r  = 0.24 and 0.35, respectively; P  < 0.05) and SUV max in the lesions of 18F-choline PET/CT ( r  = 0.28; P  < 0.0239). However, a positive but NS correlation was demonstrated between values of PSA and TMTV for each lesion in the 18F-choline PET/CT study ( r  = 0.22; P  = 0.0795). The detection rate of the different PSA levels with a cutoff of 1 ng/ml was higher for 18F-PSMA-1007 than 18F-choline.

Conclusion: In biochemical relapse patients there is a positive correlation between PSA levels in the blood and the semiquantitative parameters SUV max and TMTV of the metastatic foci in the 18F-PSMA-1007 and 18F-Choline PET/CT imaging.