68Ga-PSMA-PET/CT in Patients With Biochemical Prostate Cancer Recurrence and Negative 18F-Choline-PET/CT.

Investigating the value of Ga-PSMA-PET/CT in biochemically recurring prostate cancer patients with negative F-choline-PET/CT.

One hundred thirty-nine consecutive patients with biochemical recurrence after curative (surgery and/or radiotherapy) therapy were offered participation in this sequential clinical imaging approach.

Patients first underwent an F-choline-PET/CT. If negative, an additional Ga-PSMA-PET/CT was offered. One hundred twenty-five of 139 eligible patients were included in the study; 32 patients underwent additional Ga-PSMA-PET/CT. Patients with equivocal findings (n = 5) on F-choline-PET/CT and those who declined the additional Ga-PSMA-PET/CT (n = 9) were excluded. Images were analyzed visually for the presence of suspicious lesions. Findings on PET/CT were correlated with PSA level, PSA doubling time (dt), and PSA velocity (vel).

The overall detection rates were 85.6% (107/125) for the sequential imaging approach and 74.4% (93/125) for F-choline-PET/CT alone. Ga-PSMA-PET/CT detected sites of recurrence in 43.8% (14/32) of the choline-negative patients. Detection rates of the sequential imaging approach and F-choline-PET/CT alone increased with higher serum PSA levels and PSA vel. Subgroup analysis of Ga-PSMA-PET/CT in F-choline negative patients revealed detection rates of 28.6%, 45.5%, and 71.4% for PSA levels of 0.2 or greater to less than 1 ng/mL, 1 to 2 ng/mL, and greater than 2 ng/mL, respectively.

The sequential imaging approach designed to limit Ga-PSMA imaging to patients with negative choline scans resulted in high detection rates. Ga-PSMA-PET/CT identified sites of recurrent disease in 43.8% of the patients with negative F-choline PET/CT scans.

Clinical nuclear medicine. 2016 Mar 11 [Epub ahead of print]

Christina Bluemel, Markus Krebs, Bülent Polat, Fränze Linke, Matthias Eiber, Samuel Samnick, Constantin Lapa, Michael Lassmann, Hubertus Riedmiller, Johannes Czernin, Domenico Rubello, Thorsten Bley, Saskia Kropf, Hans-Juergen Wester, Andreas K Buck, Ken Herrmann

From the Departments of *Nuclear Medicine, †Urology, and ‡Radiation Oncology, University Hospital of Würzburg, Würzburg; §Department of Radiation Oncology, Klinikum Ansbach, Ansbach; ∥Department of Nuclear Medicine, Technische Universität München, Munich, Germany; ¶Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA; #Department of Nuclear Medicine-PET/CT Oncologic & Endocrine Sections, Rovigo Hospital, Rovigo, Italy; **Department of Radiology, University Hospital of Würzburg, Würzburg, Germany; ††Scintomics GmbH, Fürstenfeldbruck; and ‡‡Pharmaceutical Radiochemistry, Technische Universität München, Munich, Germany.