Pattern of relapse definitions. (A) Theoretical outline (pink) of initial site of disease based on the prechemotherapy PET/CT scan. A relapse within the outlined region would have been categorized as a relapse in the “initial site” of disease. A relapse outside of the outlined region would be considered a “new site” of relapse. (B) Theoretical outline (blue) of fluorodeoxyglucose-avid residual disease greater than the mediastinal blood pool on PET/CT after 1 cycle of AVPC. For PET1⁺ patients, a relapse within the blue region would be considered a relapse at the “PET1⁺ site,” whereas a relapse outside of the blue region but within the pink region from panel A would be considered “initial site beyond the PET1⁺ site.”