Background PET with gallium 68 (68Ga) prostate-specific membrane antigen (PSMA)-11 and fluorine 18 (18F) fluciclovine has influenced salvage radiation therapy (sRT) planning in postprostatectomy biochemical recurrence. Purpose To assess the comparative impact of 18F-fluciclovine and 68Ga-PSMA-11 PET/CT on sRT changes in postprostatectomy biochemical recurrence. Materials and Methods In this secondary analysis of a prospective randomized controlled trial, men with detectable prostate-specific antigen (PSA) levels after prostatectomy were randomly assigned to undergo 18F-fluciclovine PET/CT (arm A) or 68Ga-PSMA-11 PET/CT (arm B) between May 2019 and May 2023. The Clopper-Pearson binomial method was used to evaluate decision changes on whether to offer radiation therapy (RT) and to which field (with or without boost) between the pre- and post-PET time points in each arm, and to compare decision changes between the arms. Results A total of 140 eligible participants (age range, 47-83 years) were randomly assigned 1:1 to arm A (mean age, 63 years ± 8 [SD]; median pre-RT PSA level, 0.27 ng/mL) or to arm B (mean age, 65 years ± 8; median pre-RT PSA, 0.35 ng/mL). Six participants (five in the 18F-fluciclovine group and one in the 68Ga-PSMA-11 group) withdrew from the trial before undergoing PET/CT. Overall sRT decision changes occurred in 19 of 65 participants (29%) in arm A (P < .001) and 29 of 69 participants (42%) in arm B (P < .001), but there was no evidence of a difference between arms (P = .12). Among participants for whom the final decision was to offer them sRT, treatment field (and/or boost) changes occurred in 43 of 60 participants (72%) in arm A (P < .001) and 33 of 61 participants (54%) in arm B (P < .001) and were more likely with 18F-fluciclovine PET/CT than with 68Ga-PSMA-11 PET/CT (P = .046). Conclusion In postprostatectomy biochemical recurrence, the use of 18F-fluciclovine and 68Ga-PSMA-11 for PET/CT-guided sRT planning resulted in substantial treatment decision changes, but there was no difference in the likelihood of a decision change between the two radiotracers. Treatment field (and/or boost) changes were more likely with 18F-fluciclovine PET/CT than with 68Ga-PSMA-11 PET/CT. Clinical trial registration no. NCT03762759 © RSNA, 2026 Supplemental material is available for this article. See also the editorial by Iravani in this issue.
Radiology. 2026 Jun [Epub]
Olayinka A Abiodun-Ojo, Ashesh B Jani, Subir Goyal, Ismaheel O Lawal, Raghuveer K Halkar, Vishal Dhere, Joseph W Shelton, Pretesh R Patel, Eduard Schreibmann, Bruce Hershatter, Sagar A Patel, Sheela Hanasoge, Nikhil T Sebastian, David M Schuster
Department of Radiology and Imaging Sciences, Emory University School of Medicine, 1365 Clifton Rd, Atlanta, GA 30322., Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, Ga., Biostatics Shared Resource, Winship Cancer Institute of Emory University, Atlanta, Ga.