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Prostate Cancer: Staging (MP11): Moderated Poster 11: Friday, September 10, 2021

MP11-15 REAL-WORLD EVIDENCE OF 18F-FLUCICLOVINE PET/CT UTILIZATION FOR RECURRENT PROSTATE CANCER IN THE VETERAN AFFAIRS HEALTH SYSTEM

Klaassen, Zachary; Gu, Lin; Waller, Justin D.; De Hoedt, Amanda; Tainer, Nancy; Kinscherff, Jonathan; Freedland, Stephen J.

doi: 10.1097/JU.0000000000001984.15
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INTRODUCTION AND OBJECTIVE:

18F-Fluciclovine PET/CT was approved for use in 2016 for detection of biochemically recurrent prostate cancer (PC) after primary therapy. To date, there have been no population-level studies assessing utilization of 18F-fluciclovine PET/CT. The objective of this study was to assess utilization of 18F-fluciclovine PET/CT for recurrent PC in the Veterans Affairs (VA) Health System, focusing on sociodemographics, and the impact of PSA levels and use of androgen deprivation therapy (ADT) on 18F-fluciclovine PET/CT positivity rates.

METHODS:

There were 830 patients (pts) that received a 18F-fluciclovine PET/CT in the VA. A random selection of 300 pts from 44 sites were included, stratified by receipt of ADT and PSA (low <1 ng/mL vs high ≥1 ng/mL) at the time of imaging. The primary outcome was the result of 18F-fluciclovine PET/CT, categorized as positive vs negative vs equivocal. Comparison between these groups included the Kruskal-Wallis test for continuous variables and Chi-square or Fisher’s exact test for categorical variables. Logistic regression, adjusting for demographic and disease characteristics, was used to test the association between PSA, use of ADT, and race with 18F-fluciclovine PET/CT positive imaging.

RESULTS:

18F-fluciclovine PET/CT positivity rate was 33% for pts with a PSA between 0-0.5 ng/mL, 21% for >0.5-1.0, 54% for >1.0-2.0, and 66% for >2.0 (p<0.0001). Pts currently treated with ADT had a positivity rate of 59% compared to 37% for those not treated with ADT (p=0.0004). There were too few pts that started ADT within 1 (n=10) and 3 months (n=17) to perform additional analyses assessing the impact of recently starting ADT. White pts were more likely to have a positive scan compared to black (55% vs 38%; p=0.02). Pts whose primary treatment was radical prostatectomy had a lower positivity rate (33%) compared to those treated with radiotherapy (55%; p<0.0001). There was no difference in positivity rate based on PET/CT manufacturer (p=0.70). Multivariable logistic regression showed that PSA (>1 vs ≤1 ng/mL; OR 3.47, 95% CI 1.65-7.29), use of ADT (yes vs no; OR 4.34, 95% CI 1.33-14.15), and race (black vs white; OR 0.50, 95% CI 0.25-0.99) were predictive of positive 18F-fluciclovine PET/CT.

CONCLUSIONS:

This real-world study assessing utilization of 18F-fluciclovine PET/CT in an equal access health-care system confirms the impact of PSA level on scan positivity rate. Additionally, pts currently receiving ADT have a >4x higher likelihood of a positive scan, showing that scan positivity was not negatively affected by ADT status.

Source of Funding:

Blue Earth Diagnostics, Inc

© 2021 by American Urological Association Education and Research, Inc.