18F]DCFPyL PET/CT in detection and localization of recurrent prostate cancer following prostatectomy including low PSA < 0.5ng/mL.

Abstract

The primary aim of this retrospective multicenter analysis was to assess the performance of PSMA PET/CT using [18F]DCFPyL in the detection and localization of recurrent prostate cancer post radical prostatectomy (RP). Particular reference is given to low PSA groups < 0.5ng/mL to aid discussion around the inclusion of this group in PSMA guidelines and funding pathways. Retrospective analysis of combined PSMA database patients from centers in Australia and New Zealand. Two hundred twenty-two patients presenting with recurrence post RP were stratified into five PSA groups (ng/mL): 0-0.19, 0.2-0.49, 0.5-0.99, 1-1.99, and ≥ 2. Lesions detected by [18F]DCFPyL PET/CT were recorded as local recurrence, locoregional nodes, and metastases. Of 222 patients, 155 (69.8%) had evidence of abnormal uptake suggestive of recurrent prostate cancer. The detection efficacies for [18F]DCFPyL PET/CT were 91.7% (44/48) for PSA levels ≥ 2ng/mL, 82.1% (23/28) for PSA levels 1-1.99ng/mL, 62.8% (27/43) for PSA levels 0.5-0.99ng/mL, 58.7% (54/92) for PSA levels 0.2-0.49ng/mL, and 63.6% (7/11) for PSA levels ≤ 0.2ng/mL. In those with PSA < 0.5ng/mL, 47.6% (49/103) had detectable lesions, 71.4% (35/49) had disease confined to the pelvis, 22.4% (11/49) had prostate bedrecurrence, 49.0% (24/49) had pelvic lymph nodes, and 28.6% (14/49) had extra pelvic disease. [18F]DCFPyL PET/CT has a high detection rate in recurrence following RP even at low PSA levels with similar detection levels in the PSA subgroups < 0.5ng/mL. Employing rigid PSA thresholds when constructing guidelines for PSMA PET/CT funding eligibility may result in a significant number of patients below such thresholds having delayed or inappropriate treatment.