Nuklearmedizin 2020; 59(02): 152
DOI: 10.1055/s-0040-1708314
Wissenschaftliche Poster
PET, SPECT & Co. II
© Georg Thieme Verlag KG Stuttgart · New York

PSA and PSA kinetics as predictor of a positive Ga-68-PSMA-11 PET/CT scan for restaging prostate cancer

MA Hoffmann
1   Federal Ministry of Defense, Department of Occupational Health & Safety, Bonn
,
HG Buchholz
2   Johannes Gutenberg-University, Clinic of Nuclear Medicine, Mainz
,
HJ Wieler
3   Bundeswehr Central Hospital, Clinic of Nuclear Medicine, Koblenz
,
F Rosar
4   Saarland University Medical Center, Department of Nuclear Medicine, Homburg
,
M Schreckenberger
2   Johannes Gutenberg-University, Clinic of Nuclear Medicine, Mainz
› Author Affiliations
Further Information

Publication History

Publication Date:
08 April 2020 (online)

 

Ziel/Aim The purpose of the present study was to determine the best time for performing Ga-68-PSMA-11 PET/CT scans in a large cohort of patients by identifying prostate-specific-antigen (PSA) and PSA kinetics thresholds for detecting and localizing recurrent prostate cancer (PCa).

Methodik/Methods This retrospective analysis included 619 patients with a biochemical recurrence by definition. The performance of Ga-68-PSMA-11 PET/CT in relation to the PSA value at the time of the scans as well as PSA kinetics was assessed by receiver-operating-characteristic-curve (ROC) generating by plotting sensitivity versus 1-specificity.

Ergebnisse/Results Ga-68-PSMA-11 PET/CT revealed malignant prostatic lesions in 483/619 patients (78 %). A PSA value of 1.24 ng/mL was found to be the optimal cut off-level for predicting positive and negative scans by means of ROC analysis (AUC=0.779; 95 % CI 0.737-0.821). For patients treated with radical prostatectomy (370/493 Group A), the optimal cut off-level was also 1.24 ng/mL. While for patients which had previously been treated with radiotherapy (113/126 Group B), it was 5.75 ng/mL. In patients with a PSA value <1.24 ng/mL, 52 % (92/177) (A)/<5.75 ng/mL, 86.1 % (62/72) (B) Ga-68-PSMA-11 PET/CT scans were positive, whereas patients with a PSA ≥1.24 ng/mL (A)/≥5.75 ng/mL (B) exhibited positive scan results in 87.4 % (278/316) (p<0.001) (A)/94.4 % (51/54) (p=0.002) (B). The optimal PSA velocity threshold from ROC analysis for the detection of recurrent PCa-lesions was 1.32 ng/mL/year (AUC=0.777; 95 % CI 0.709-0.845) for patients treated with radical prostatectomy, which showed significant differences between PET-positive and PET-negative scans (p<0.001).

Schlussfolgerungen/Conclusions This study identifies PSA and PSA kinetics threshold levels, in a large population of patients, for the presence of Ga-68-PSMA-11 PET/CT-detectable lesions in patients with recurrent prostate cancer.