18F-rhPSMA-7 positron emission tomography for the detection of biochemical recurrence of prostate cancer following radical prostatectomy.

18F-labelled prostate-specific membrane antigen (PSMA) positron emission tomography (PET) tracers are increasingly used in preference to 68Ga-PSMA-11 for restaging biochemical recurrence (BCR) of prostate cancer. They are associated with longer half-lives, larger scale production and lower positron range compared with their 68Ga-labelled counterparts. Here we describe the efficacy of 18F-labelled radiohybrid PSMA, rhPSMA-7, a novel theranostic PSMA-targeting agent for imaging BCR of prostate cancer. Methods: Datasets from 261 consecutive patients with non-castrate BCR after radical prostatectomy who underwent 18F-rhPSMA-7 PET/CT at our institution between June 2017 and March 2018 were reviewed retrospectively. All lesions suspicious for recurrent prostate cancer were recorded. The detection rate of presumed recurrence sites was correlated with patients' PSA level, primary Gleason score, and prior therapy (androgen deprivation therapy [ADT)] and external beam radiation therapy [EBRT]). Results: The 261 patients had a median PSA level of 0.96 (range, 0.01-400) ng/mL. The median injected activity of 18F-rhPSMA-7 was 336 MBq, with a median uptake time of 76 min. In total, 211 patients (81%) patients showed pathological findings on 18F-rhPSMA-7 PET/CT. The detection rates were 71% (42/59), 86% (44/51), 86% (42/49) and 95% (76/80) at PSA levels of 0.2 to <0.5 ng/mL, 0.5 to <1 ng/mL, 1 to <2 ng/mL and ≥2 ng/mL, respectively. In 32% (7/22) patients with a PSA <0.2 ng/ml suspicious lesions were present. 18F-rhPSMA-7 PET/CT revealed local recurrence in 43% (113) patients. Lymph node metastases were present in the pelvis in 42% (110), in the retroperitoneum in 17% (45) and in a supradiaphragmatic location in 8.0% (21) patients. Bone and visceral metastases were detected in 21% (54) and 3.8% (10) patients, respectively. Detection efficacy was not influenced by prior EBRT (79.1% vs. 82.1%, P = 0.55), ADT within the 6 months preceding imaging (80.6% vs. 80.9%, P = 0.54), nor by primary Gleason score (77.9% for Gleason Score ≤7 vs. 82.6% for Gleason Score ≥ 8, P = 0.38). Conclusion:18F-rhPSMA-7 PET/CT offers superb detection rates in early BCR after radical prostatectomy, especially among patients with low PSA values.

Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2019 Dec 13 [Epub ahead of print]

Matthias Eiber, Markus Krönke, Alexander Wurzer, Lena Ulbrich, Lena Jooß, Tobias Maurer, Thomas Horn, Kilian Schiller, Thomas Langbein, Gabriel Buschner, Hans-Jürgen Wester, Wolfgang A Weber

Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Nuclear Medicine, Munich, Germany, Germany., Chair for Pharmaceutical Radiopharmacy, TUM, Garching, Germany., Martini-Klinik and Department of Urology, University Hospital Hamburg Eppendorf., Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Urology., Department of Radiation Oncology, Klinikum rechts der Isar, TUM.