Overview and Recent Advances in 18F-FDG PET/CT for Evaluation of Pediatric Lymphoma

• Published in: Seminars in nuclear medicine 2023-05, Vol.53 (3), p.400-412
• Main Authors: Guja, Kip E., Nadel, Helen, Iagaru, Andrei
• Format: Article
• Language: English
• ISSN: 0001-2998; 1558-4623
• DOI: 10.1053/j.semnuclmed.2022.10.001

Pediatric lymphoma is the third most common childhood cancer, representing 15% of all pediatric malignancies. Evaluation of the extent of disease with imaging is essential for appropriate risk stratification and treatment planning, and has evolved extensively over the past several decades. At present, PET/CT plays a key role in the diagnostic evaluation of these patients, particularly for staging, treatment planning, and therapy response assessment. The vast majority of pediatric lymphomas are FDG avid and as a result, FDG PET/CT has a higher sensitivity for detecting sites of disease compared to conventional imaging modalities, as well as a higher sensitivity for detecting focal bone marrow lesions compared to standard bone marrow biopsy of the iliac crest. PET/CT can be used to identify early responders, helping to minimize overtreatment with intensive chemotherapy and radiotherapy, thereby reducing the risk of secondary malignancies and cardiovascular complications. Conversely, PET/CT can identify patients with an inadequate metabolic response during treatment, who can then benefit from earlier treatment intensification. A negative interim or end of treatment FDG PET/CT is highly predictive for a complete remission, although positive PET/CT scans, particularly at end of treatment, have a lower PPV and must be interpreted cautiously. Nevertheless, PET/CT is more accurate than conventional imaging alone, as well as in the case of conflicting results, such as residual lymph node enlargement and soft tissue lesions that can that can persist despite resolution of the underlying malignancy. For these reasons, FDG PET/CT has been incorporated into the standard diagnostic procedures for lymphoma staging and treatment response evaluation, using the visual Deauville 5-point scale and Lugano classification. In the future, innovations in low-dose ultrafast total-body PET/CT, increased use of PET/MR and incorporation of quantitative parameters from PET such as total metabolic tumor volume may allow even more precise prediction of response and personalized therapy while minimizing radiation exposure and adverse effects and complications of treatment.