The Role of 18F-FDG PET/CT in Follow up After Treatment in Childhood Langerhans Cell Histiocytosis.

Abstract

Objectives: To demonstrate the value of FDG PET/CT in follows up after treatment of patients with childhood Langerhans cell histiocytosis (LCH). Patients and Methods: A retrospective analysis of thirty pediatric patients with histopathologically proven LCH from September 2013 till November 2016 with follow up for 36 months. All patients received specific therapy for LCH in the form of chemotherapy &/or surgical resection. Analysis criteria at initial assessment included the following: any focal FDG uptake was considered abnormal when it was greater than that of hepatic uptake or in presence of abnormal changes on CT with any degree of FDG uptake. Results: 21 patients (70 %) presented with multi-system disease (bone as well as LNs &/or liver, lungs, soft tissue and skin), 6 patients (20%) had uni-focal lesions and 3 patients (10%) presented by multi-focal lesions. Follow up FDG PET/CT after therapy detected metabolic changes earlier than structural changes detected by CT. At the end of study 21 patients (70%) were disease free with nine patients (30%) had residual active disease. No statistically significant difference could be detected in relation to overall survival in relation to disease extent or risk group. Conclusion: F-18 FDG PET/CT is valuable in detection of response therapy. Survival was better in patients with unifocal disease and those of low risk group.