The role of PET in the first-line treatment of the most common subtypes of non-Hodgkin lymphoma

This Review focuses on the use of 18F-fluorodeoxyglucose (18F-FDG) PET in the assessment of diffuse large B-cell lymphoma, follicular lymphoma, and peripheral T-cell lymphoma. PET is important for staging and prognostication with stage migration compared with CT. Better outcomes for patients with early stage diffuse large B-cell lymphoma and follicular lymphoma suggests better delineation of disease has translated to improved outcomes in such patients beyond simple stage migration. The aim of treatment of diffuse large B-cell lymphoma and peripheral T-cell lymphoma is potential cure, during which PET is mainly used to assess remission. Interim PET can assess chemosensitivity in these lymphomas, but it does not predict treatment success sufficiently well to enable treatment modification, particularly in the absence of more effective therapies for patients who remain PET-positive on interim scanning. In follicular lymphoma, traditionally viewed as an incurable lymphoma, the aim of treatment is to control disease for several years, while maintaining quality of life. PET can predict prognosis for patients with follicular lymphoma with high tumour burden at the end of induction chemotherapy, and it is being evaluated as a platform for response-adapted treatment of follicular lymphoma.