A Prospective Provincial PSMA-PET Registry for Recurrent Prostate Cancer: Preliminary results

Abstract

To compare detection of disease with 18F-DCFPyL PET/CT (PET) versus conventional imaging (CI; CT and bone scan) for patients with undetectable or oligometastatic prostate cancer recurrence on CI, and to assess subsequent change in management. PREP was organized as a Registry Study with six participating sites and a target accrual of 1500 men. Eligibility included biochemical failure with no or limited (≤4 sites) disease on CI and 1 of 6 predefined clinical scenarios (Table). From December 1, 2018 to October 31, 2019, 410 men were enrolled. Overall, 261/410 men (64%) had PET-detected lesions. PET detected disease sites in 174/310 men (56%) with negative conventional imaging. Among men with disease sites detected on conventional imaging, new lesions were seen on PET in 63/100 (63%). PSA at enrolment was available for 408/410 patients, and the detection rate of disease by PSA at enrollment was: 54/139 (39%) for PSA <0.5; 49/78 (63%) for PSA 0.5-1.0 and 157/191 (82%) for PSA >1.0. 149/410 men (36%) had no disease detected, 144/410 men (35%) had recurrent disease localized to the pelvis and 117/410 men (29%) had extra-pelvic disease (with or without pelvic disease). 232/410 men (57%) had potentially “actionable” disease: loco-regional or oligometastatic disease (≤4 distant metastases). Post-PET questionnaires were completed in 341/410 men and 66% (226/341) had a PET-directed change in management. After PET, management intent changed from palliative to radical in 84/341 (25%) and from radical to palliative in 32/341 (9%). After PET, lesion-directed therapy for locoregional or oligometastatic recurrence was added in 135/341 (40%). For patients with local only disease, pelvic nodal disease, and distant metastatic disease on PET, 69%, 79%, and 79% had a change in planned management. 18F-DCFPyL PET/CT access, facilitated through the PREP Registry Study, has resulted in detection of more sites of disease and has impacted both local salvage planning and treatment intent (radical versus palliative).Abstract 4043; TableCohortNumber in cohortMedian PSA% CI positive% PET positive% Management changeOverall4100.9024%64%66% (226/341)N+ or detectable PSA post RP260.9112%27%61% (14/23)BF post RP1550.4417%47%62% (85/137)BF post RP + RT1390.9523%68%66% (79/119)BF post RP or RT + ADT182.7972%89%54% (7/13)BF post Rx for oligometastases82.8663%100%71% (5/7)BF post RT464.7922%87%88% (23/26)CI: conventional imaging; PSA: Prostate Specific Antigen; N+: node positive; RP: Radical Prostatectomy; BF: Biochemical failure; Rx: Treatment; RT: Radiotherapy; ADT: Androgen Deprivation Therapy; PET: Positron Emission Tomography Open table in a new tab