The EMPIRE-1 trial showed that incorporating fluciclovine PET/CT into treatment planning for salvage prostate radiation improved disease-free survival. This secondary analysis asked whether the incorporation of fluciclovine PET findings resulted in larger target volumes and increased toxicity. Prior to PET findings, there was no difference in the pelvic node plus fossa volume (CTV1) or the prostate fossa alone (CTV2) volume. Incorporation of PET findings resulted in a small but significant increase in CTV1 (455cc v 461cc) and CTV2 (134cc v 136cc). These changes did not significantly increase the V40 or V65 of the rectum and bladder but did increase penile bulb dose. | Dhere, Int J Radiat Oncol Biol Phys 2022