Abstract
Purpose: A first analysis of simultaneous 68Ga-PSMA-11 PET/MRI showed some improvement in the detection of recurrent disease at low serum prostate specific antigen (PSA) values below 0.5 ng/ml compared to the already high detection rate of 68Ga-PSMA-11 PET/CT. We therefore focused on all patients with biochemical recurrence (BR) and PSA values ≤ 0.5 ng/ml to assess the detection rate for 68Ga-PSMA-11 PET/MRI. Methods: We retrospectively analyzed a cohort of 66 consecutive patients who underwent a 68Ga-PSMA-11 PET/MRI for BR with a PSA value ≤ 0.5 ng/ml at our institution. Median PSA level was 0.23 ng/ml (range: 0.03 – 0.5 ng/ml). Detection of PSMA-positive lesions within the prostate fossa, local and distant lymph nodes, bones or visceral organs was recorded. In addition, all scans with 68Ga-PSMA-11 PET/MRI positive lesions were retrospectively assessed to analyze if lesions were detected inside or outside of a standard salvage radiotherapy volume. Results: Overall, in 36 of 66 patients (54.5%) PSMA-positive lesions were detected; in 26 of 40 (65%) patients with a PSA between 0.2 - 0.5 ng/ml and in 10 of 26 (38.5%) patients with a PSA < 0.2 ng/ml. Even at those low PSA values, only 8 of 66 (12.1%) patients had exclusive local recurrence. In 23 patients lymph nodes and in 5 patients bone metastases were detected on 68Ga-PSMA-11 PET/MRI. In 26 of 66 patients (39.4%) PSMA-positive lesions were located outside a standard salvage radiotherapy volume. Conclusion: Our data confirm that 68Ga-PSMA-11 PET/MRI has a high detection rate for recurrent prostate cancer, even at low PSA levels ≤ 0.5 ng/ml. In addition, we show that 68Ga-PSMA-11 PET/MRI detected PSMA-positive lesions outside a standard salvage radiotherapy volume in 39.4% of all patients.
- Oncology: GU
- PET
- PET/MRI
- 68Ga-PSMA-11
- PSMA Antigen
- Positron Emission Tomography
- Prostate Cancer
- Prostate-Specific Antigen
- Copyright © 2019 by the Society of Nuclear Medicine and Molecular Imaging, Inc.