Single Institution Patterns of Management of (18)F-Fluciclovine-detected Prostate Cancer Recurrences

Abstract

Multiple prostate-cancer directed positron emission tomography (PET) radiotracers have emerged and (18)F-fluciclovine (Axumin) is the most recent agent that has been approved by the US Food and Drug Administration for detection of recurrent prostate cancer (PCa). We report the treatments and outcomes of patients at our institution who had Axumin PET-detected PCa recurrences. We retrospectively identified men with PCa who underwent Axumin PET (Ax-PET) between 2017 and 2018 focusing on men with nonmetastatic PCa previously treated with either surgical resection ± radiation (RT) or definitive RT ± androgen deprivation therapy (ADT). Of these patients, those with recurrent PCa seen on Ax-PET were analyzed for patterns of care and PCa related outcomes. We identified 27 men with nonmetastatic PCa who had recurrent PCa detected on Ax-PET. Twenty-three were initially treated with surgery (median Gleason score 7, median PSA 9.76ng/mL) Of the 23 surgical patients, 17 pathologic node negative patients had indication for postoperative radiation (PORT). 10 men received PORT (5 adjuvant, 5 salvage), 3 with concurrent ADT. The median dose of PORT was 66Gy to the prostate fossa. Four patients were initially treated with definitive RT (2 with ADT) to median dose 76Gy to prostate ± seminal vesicles (median Gleason score 6.5, median PSA 10.1ng/mL). In the surgical patients, the median time to Ax-PET was 67 months with a median PSA of 1.63ng/mL. In the patients initially treated with RT, the median time to Ax-PET was 73 months with median PSA of 2.74ng/ml. In all patients, median time to Ax-PET was 73 months with median PSA 2 (range 0.16-94.18). Seven men recurred in the prostate bed and lymph nodes (median PSA 4.2), 18 recurred in lymph nodes alone (median PSA 0.95), three recurred in lymph nodes and bone (median PSA 46.88ng/mL), and one recurred in bone only (PSA 59.17). Median size of Ax-PET avid lymph nodes was 0.8mm. After Ax-PET, three patients were treated with surgery alone with pathologic correlation in 2/3 patients. Median postoperative PSA declined from 0.84 to 0.13ng/mL. Seven patients were treated with RT (3 with concurrent ADT) with median PSA decline from 0.8 to 0.07ng/mL. Eleven patients were treated with ADT alone with median PSA decline from 4.11 to 2.83ng/mL. Eight patients received no further treatment after Ax-PET. (18)F-Fluciclovine Axumin PET can localize prostate cancer recurrences in the prostate bed, regional lymph nodes, or bone. Focal treatment with surgery or radiation appears effective with decreasing PSA. Longer follow-up is required to see if these diagnostic tests and subsequent therapy will lead to increased prostate cancer specific survival.