FDG-PET(CT)-adapted trials in non-Hodgkin lymphoma

18-F-fluorodeoxyglucose (FDG)-positron emission tomography (PET), is identified as a strong diagnostic and prognostic tool in patients with diffuse large B cell lymphomas (DLBCL), primary mediastinal B cell lymphomas and follicular lymphomas (FL), and its routine use has been recommended in the recently updated criteria for staging and response assessment in lymphomas. Evidences on the role of FDG-PET in foreseeing the outcome of patients with aggressive, and lately FL, have paved the way for several prospective trials that are underway to evaluate either escalation or de-escalation approaches based on the results of both interim and end-of-treatment FDG-PET. These trials are trying to answer important questions that represent real challenges for the management of patients with non-Hodgkin lymphomas. These range from the utility of radiotherapy after induction immunochemotherapy (ICT) in patients with residual masses, to the need and modality for treatment intensification in high-risk patients with DLBCL, to the real need of maintenance therapy in patients with FL responding to initial ICT.