Can FDG‐PET replace biopsy for the evaluation of residual tumor in pediatric mature B‐cell non‐Hodgkin lymphoma?

Abstract

Introduction The aim of our study is to evaluate the role of 18F‐labeled fluorodeoxy glucose positron emission tomography (18FDG‐PET) scan for the detection of viable residual mass in pediatric mature B‐cell non‐Hodgkin lymphoma (NHL). This study also aims to detect the negative predictive value, positive predictive value (PPV), sensitivity, and specificity of 18FDG‐PET. Patients and methods A retrospective, cross‐sectional nonrandomized study was carried out. We included all patients with newly diagnosed mature B‐cell NHL treated at the Children Cancer Hospital Egypt during the period between July 2007 and the end of May 2018. Patients were included in the study if they (a) had a residual tumor mass, (b) underwent an 18FDG‐PET scan, and (c) had a pathologic documentation of this residual tumor. Patients were followed up till June 2019. Results Thirty‐six patients were included, for whom 39 biopsies were performed. Mean age was 7.7 years. Median follow‐up period was 52.8, range 6.1 to 117 months.18FDG‐PET scan was positive (Deauville score 3, 4, or 5) in 24 of 39 patients (61.5%), while it was negative (Deauville score 1 or 2) in 15 patients (38.5%). Positive 18FDG‐PET scan and biopsy were performed in 15 of 39 samples (38.4%; true positive, TP), while they were both negative in 13 samples (33.3%; true negative). Nine patients (23%) had positive scan and a negative biopsy (false positive), while 2 patients had negative uptake and a positive biopsy (false negative, FN)). Sensitivity of the 18FDG‐PET scan was 88.2% and specificity was 59.1%. PPV was 62.5% and NPPV was 86.6%. Conclusion Changing therapy on the basis of a positive finding alone at the time of evaluation is not recommended. FN results exist, so biopsy confirmation is required to avoid the missing refractory disease. If negative, 18FDG‐PET can replace a biopsy if the latter is inaccessible or carries an unnecessary risk.

64Cu-DOTA-Rituximab PET/CT of B-Cell Non-Hodgkin Lymphoma for Imaging the CD20 Expression

“…Some researchers reported that most of lymphoma patients showed 18 F-FDG–avid lesions including the mantle cell lymphoma and follicular lymphoma 1–3 . However, we found out that in some cases it is not easy to delineate the lymphoma lesions using 18 F-FDG PET/CT 4,5 without 64 Cu-DOTA-rituximab PET/CT. 64 Cu-DOTA-rituximab PET/CT could be a powerful tool for the diagnosis and monitoring treatment response of lymphoma because of imaging the CD20 expression 6,7 .…”

Die Rolle der [18F]FDG PET/CT bei pädiatrischen Lymphomen

“…[18]. Insbesondere bei asymptomatischen Kindern und Jugendlichen wird daher eine Bestätigung durch eine Biopsie empfohlen, sofern dies auch möglich ist [19]. Falsch-positive Ergebnisse wurden auf zeitnah vor der PET erfolgt Biopsien, reaktive Lymphknoten bzw.…”