Diagnostic performance of 18F-fluciclovine PET/CT in prostate cancer patients with rising PSA level ≤ 0.5 ng/ml after multiple treatment failures

This retrospective study is to assess the performance of 18 F-Fluciclovine PET/CT in prostate cancer (PC) patients with multiple treatment failures and prostate-specific antigen (PSA) ≤ 0.5 ng/mL. PC patients with multiple treatment failures who had PSA level within 2-week interval of 18 F-Fluciclovine PET/CT (PSA PET ) ≤ 0.5 ng/mL were identified in retrospective review of our institution’s database (n=28). Patient, tumor, treatment, PSA and castration characteristics as well as findings on 18 F-Fluciclovine PET/CT were collected and compared between positive and negative 18 F-Fluciclovine PET/CT subgroups by using Fisher’s exact test. The overall detection rate of 18 F-Fluciclovine PET/CT was 7 of 28 studies (25%). PSA PET > 0.2 ng/mL was associated with higher detection rates in all (33.3 vs 10%, P =0.172), castration-resistant (CR) (50 vs 20%, P =0.343) and castration-sensitive (CS) (28.6 vs 0%, P =0.179) patients. Sites of recurrence were local 42.9% (3/7), nodal 42.9% (3/7) and bone metastases 14.3% (1/7). Higher Gleason score (GS 8-10) (33.3 vs 14.5%, P =0.396), advanced tumor stage (T3-T4) (35.7 vs 20%, P =0.653), second-line androgen deprivation therapy (ADT) uses (66.7 vs 20%, P =0.145), chemotherapy uses (50 vs 23.1%, P =0.444) and CRPC (33.3 vs 21.1%, P =0.483) related to positivity of 18 F-Fluciclovine PET/CT but none reached statistical significance. Performance of 18 F-Fluciclovine PET/CT in prostate cancer patients with multiple treatment failures and PSA PET ≤ 0.5 ng/mL was acceptable particularly in patients with PSA PET ≥ 0.3 ng/mL, CRPC, initial GS ≥ 8 or T3-T4.