TY - JOUR T1 - The change in management by <sup>18</sup>F-DCFPyL PSMA PET scanning in patients undergoing post-prostatectomy radiotherapy, with early biochemical response outcomes. JF - Journal of Nuclear Medicine JO - J Nucl Med DO - 10.2967/jnumed.121.263521 SP - jnumed.121.263521 AU - Michael Ng AU - Mario Guerrieri AU - Lih Ming Wong AU - Kim Taubman AU - Tom Sutherland AU - Angela Benson AU - Graeme Byrne AU - Sam Koschel AU - Kelvin Yap AU - Grace Ong AU - Craig Macleod AU - Marcus Foo AU - Michael Chao Y1 - 2022/01/01 UR - http://jnm.snmjournals.org/content/early/2022/01/20/jnumed.121.263521.abstract N2 - Rationale: Prostate specific membrane antigen (PSMA) tracers have increased sensitivity in detection of prostate cancer compared to conventional imaging. We assessed the management impact of 18F-DCFPyL PET/CT in patients with PSA recurrence post radical prostatectomy (RP) and report early biochemical response in patients who underwent radiation treatment. Methods: One-hundred patients were enrolled into a prospective study, with a prior RP for prostate cancer, PSA 0.2-2.0ng/mL and no prior treatment. All patients underwent a diagnostic CT and 18F-DCFPyL PSMA PET/CT, and management intent was completed at 3 times points (original, post-CT and post-PSMA) and compared. Patients who underwent radiotherapy with 6-month PSA response data are presented. Results: Ninety-eight patients are reported with a median PSA 0.32 ng/mL (95% CI 0.28-0.36), with 71.4% pT3a/b disease and International Society of Urological Pathology (ISUP) grade group ≥3 in 59.2%. 18F-DCFPyL PET/CT detected disease in 46.9% of patients compared to 15.5% using diagnostic CT (PSMA PET 29.2% local recurrence and 29.6% pelvic nodal disease). Major change in management intent was higher post-PSMA vs post-CT (12.5% vs 3.2%, P = 0.010) and similarly, moderate change in intent (31.3% vs 13.7%, P = 0.001). The most common change was an increase recommendation of elective pelvic radiation (15.6% to 33.3%), nodal boost (0% to 22.9%) and concurrent androgen deprivation therapy (ADT) use (22.9% to 41.7%) from original to post-PSMA intent due to detection of nodal disease. 86 patients underwent 18F-DCFPyl guided radiotherapy. 55/86 patients did not receive ADT or ADT recovered with 18 month PSA response from 0.32 ng/mL to 0.02 ng/mL, 94.5% of patients with PSA ≤0.20ng/mL and 74.5% with PSA ≤0.03 ng/mL. Conclusion: 18F-DCFPyL PET/CT has significant impact to management intent in patients being considered for salvage radiotherapy post-RP with PSA recurrence. Increased detection of disease, particularly in the pelvic lymph nodes resulted in increased pelvic irradiation and concurrent ADT use. Early results in patients who are staged with 18F-DCFPyL PET/CT-staged show favourable PSA response. ER -