Patterns of PSMA PET/CT scan usage for initial staging and recurrence in a multi-centered hospital system.

Abstract

36 Background: PET PSMA-based imaging for prostate cancer staging has been approved since late 2020 and was widely available in our medical system by July 2021. We sought to examine the patterns of use of PSMA PET/CT and conventional imaging for staging since this time. Methods: We retrospectively identified men who were diagnosed with presumptive NCCN unfavorable intermediate risk (UIR), high risk, or very high risk (VHR) and men who underwent staging work-up for biochemical recurrence (BCR) from July 2021 – June 2023. Patient clinical, pathological, and imaging variables were collected. Sufficient conventional imaging for initial staging was defined as the use of a bone scan and one or more of an MRI or CT scan. The date of staging was determined by the initiation of staging with conventional imaging or the date of PSMA scan if used. Results: In the study period, 899 men were diagnosed with presumptive NCCN UIR-VHR disease. Among these individuals 32% (290/899) underwent no or insufficient staging, 26% (230/899) underwent staging with conventional imaging only, and 42% (379/899) underwent initial staging evaluations that included PET PSMA. The frequency of PET PSMA used for initial staging increased from 24% (20/82) to 80% (167/208) over the 2-year study period. 1173 men with biochemical recurrence who underwent a staging work-up were identified. Median PSA of these men was 1.37 ng/mL (IQR 0.23, 6.59 ng/mL). The frequency of PET PSMA imaging increased in these men from 91% (225/246) to 98% (296/303) over the 2-year study period. When ordering both PSMA and conventional imaging for initial staging, providers tended to order PSMA scans after initial conventional imaging orders (72%) rather than before (18%) or on the same day (11%). Conclusions: The use of PSMA PET/CT imaging rose since its implementation in our system in July 2021 with PSMA PET being utilized in 80% of patients being initially staged and 98% of those staged at BCR. Conventional imaging and Axumin PET are rarely used in BCR. If both PET PSMA and conventional imaging were ordered for initial staging, PET PSMA was typically performed after conventional imaging. Growing data may inform best sequencing and use of conventional imaging in the PSMA-PET era.