Methods: This was a retrospective study from February 2015 to January 2017 of 50 patients staged using PSMA PET/CT and mpMRI, who then underwent radical prostatectomy. Pre-operative PSMA PET/CT and mpMRI were paired with their corresponding histological tumor.
Results: A total of 81 lesions were identified by histopathology. Fifty index lesions were detected across the three modalities: 50 by histopathology (gold standard), 50 by PSMA PET/CT, and 47 by mpMRI. Thirty-four intra-prostatic secondary lesions were detected: 31 by histopathology, 31 by PSMA PET/CT, and 17 by mpMRI. PSMA had better sensitivity for index lesion localization than mpMRI (81.1% vs. 64.6%). mpMRI failed to detect 18 histology-confirmed lesions (3 index, 15 secondary) in 16 patients. Specificity for mpMRI and PSMA PET/CT was similar (84.6% vs. 82.7%). SUVmax of index lesions ranged from 2.9 to 39.6 (M=9.27 ± 6.41). There was good differentiation between background SUV and lesion SUVmax (R=0.24, p=0.09). Index
lesion SUVmax was positively correlated with PSA (R=0.41, p=0.004) and ISUP grade (R=0.48, p<0.001).
Conclusion: PSMA-PET/CT provided superior detection of prostate cancer lesions with better sensitivity than mpMRI. PSMAPET/CT can be used to enhance locoregional mpMRI to provide improved detection and characterization of lesions.
Speaker: Matthew Winter, USC California, USA
Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre, @GoldbergHanan, at the 18th Annual Meeting of the Society of Urologic Oncology, November 29-December 1, 2017 – Washington, DC