Role of F-18 FDG PET/CT in pediatric malignant lymphoma (PML)

Objectives PML accounts for 10-15% of all pediatric cancers, peak age incidence 5-9 yrs. Hodgkin’s disease (HD) represents 40% &v non-Hodgkin’s Lymphoma (NHL) 60% of PML. Chemoth. is usually the first & most common mode of treatment (TRT). Choice of TRT & predicting prognosis depend on histological type, initial staging, evaluating treatment response (ETR) & detection of early recurrence. Conventional imaging modalities (CIM) have limitations. PET/CT is more accurate; so far the literature lacks reports of large groups of pts.

Methods Report the role of F-18 FDG PET/CT for 7 it’s impact on pt. mgmt. All findings were proven histopathologically, clinically & with long-term follow-up. Patient population: 106 PET/CT studies for 74 pts (19 F &55 M) with histologically proven PML (51 HD, 23 NHL). 16 pts initial staging; 23 early ETR after 2-3 cycles chemo, 23 ETR 4-6 wks after end of TRT & 12 pts for long-term follow-up. Results of PET/CT compared with CMI.

Results Sensitivity (Sens), specificity (Spec), accuracy (Acc), positive (PPV) & negative (NPV) predictive values of PET/CT & CIM were as follows:TABLEIn 16 pts imaged for initial staging PET/CT changed staging in 6/16 (37.5%): upstaged 4 & down staged 2 & accordingly changed TRT.

Conclusions PET/CT in PMC is more accurate than CIM. We recommend that this should be the first modality for initial staging, ETR & follow-up.