Dual-Time Point [⁶⁸Ga]Ga-PSMA-11 PET/CT Hybrid Imaging for Staging and Restaging of Prostate Cancer

• Main Authors: Manuela A. Hoffmann, Hans-Georg Buchholz, Helmut J Wieler, Florian Rosar, Matthias Miederer, Nicolas Fischer, Mathias Schreckenberger
• Format: Article
• Language: English
• Published: MDPI AG 2020-09-01
• Series: Cancers
• Subjects: [⁶⁸Ga]Ga-PSMA PET/CT; prostate cancer; dual-time point imaging; delayed imaging; biphasic imaging; lesion positivity rate
• Online Access: https://www.mdpi.com/2072-6694/12/10/2788

Routine [⁶⁸Ga]Ga-PSMA-11 PET/CT (one hour post-injection) has been shown to accurately detect prostate cancer (PCa) lesions. The goal of this study is to evaluate the benefit of a dual-time point imaging modality for the staging and restaging of PCa patients. Biphasic [⁶⁸Ga]Ga-PSMA-11 PET/CT of 233 patients, who underwent early and late scans (one/three hours post-injection), were retrospectively studied. Tumor uptake and biphasic lesion detection for 215 biochemically recurrent patients previously treated for localized PCa (prostatectomized patients (P-P)/irradiated patients (P-I) and 18 patients suspected of having primary PCa (P-T) were separately evaluated. Late [⁶⁸Ga]Ga-PSMA-11 PET/CT imaging detected 554 PCa lesions in 114 P-P patients, 187 PCa lesions in 33 P-I patients, and 47 PCa lesions in 13 P-T patients. Most patients (106+32 P-P/P-I, 13 P-T) showed no additional PCa lesions. However, 11 PSMA-avid lesions were only detected in delayed images, and 33 lesions were confirmed as malignant by a SUVmax increase. The mean SUVmax of pelvic lymph node metastases was 25% higher (<i>p</i> < 0.001) comparing early and late PET/CT. High positivity rates from routine [⁶⁸Ga]Ga-PSMA-11 PET/CT for the staging and restaging of PCa patients were demonstrated. There was no decisive influence of additional late imaging with PCa lesion detection on therapeutic decisions. However, in a few individual cases, additional delayed scans provided an information advantage in PCa lesion detection due to higher tracer uptake and improved contrast.