[End of treatment evaluation in patients with aggressive non-Hodgkin's lymphoma]. / Comment établir le bilan de fin de traitement des patients atteints de lymphomes non-hodgkiniens (LNH) de malignité intermédiaire ou élevée?

Incomplete regression of a lymphomatous mass after chemotherapy and/or radiotherapy constitutes a major problem in the treatment of lymphoma. In patients with persisting tumor, it could be reasonable to use salvage therapy and possibly hematopoietic stem cell transplantation at the time of minimal disease rather than at the time of clinically overt relapse. The authors reviewed the most appropriate imaging techniques for the assessment of response to treatment. The limitations of CT and MRI for predicting the nature of residual masses are well known. 67Ga scintigraphy has become a standard procedure for the posttreatment evaluation of patients with lymphoma, but it appears that 18F-FDG PET may be a more effective method. Personal experience in the field of PET scan is reported. Although PET should be considered the noninvasive imaging modality of choice, a histological confirmation of residual disease is always necessary before starting salvage therapy. 18F-fluorodeoxyglucose is not a tumor specific radiotracer.

Whole-body 18F-FDG PET for the evaluation of patients with Hodgkin's disease and non-Hodgkin's lymphoma.

Whole-body metabolic information provided by 18F-FDG PET could help in the evaluation of lymphoma patients at diagnosis and follow-up. We studied 60 patients, 42 at initial presentation and 18 for disease recurrence (23 aggressive non-Hodgkin's lymphoma, 21 low-grade non-Hodgkin's lymphoma and 16 Hodgkin's disease). All patients underwent a clinical examination, computed tomography (CT) and a non-attenuated PET scan within 1 week. The patients received 222-296 MBq (6-8 mCi) 18F-FDG intravenously and emission scans were recorded 45-90 min later. 18F-FDG PET detected more lymph nodes than the clinical examination or CT, but this rarely resulted in upstaging (two patients). The concordance between PET and CT for the evaluation of the spleen, liver and digestive tract was quite good. Discordance was noted in 12 patients for the evaluation of bone marrow infiltration, but confirmation by MRI or focal biopsy was not always obtained. We conclude that non-attenuated 18F-FDG PET is an easy and efficient whole-body method for the evaluation of patients with lymphomas. Compared with conventional techniques, however, it does not appear to offer much improvement for staging but provides a satisfactory base for follow-up.