PET/CT and MIBG scans in diagnosis and management of Neuroblastoma

Abstract

Introduction and aim: Several studies report conflicting results about ¹⁸F-FDG/PET and MIBG scans and their diagnostic as well as prognostic significance in children with neuroblastoma. The current study was meant to evaluate both modalities and to compare them in relation to standardized modes of evaluation.

Patients and Methods: Paired evaluation (¹⁸F-PET/CT and MIBG) was carried out prospectively (within a time interval of 1 month) at diagnosis and at different points of therapy, between June 2012 and April 2013. Thirty patients (14 males and 16 females), aged (0-18 years), diagnosed with Neuroblastoma at Children’s Cancer Hospital-Egypt. They were treated according to COG A3973 for high risk patients and COG A3961 for intermediate risk patients.

Results: FDG/PET showed good results in detecting NB at all sites. FDG/PET also showed a higher sensitivity and specificity, and a better PPV/NPV than MIBG which was not statistically significant. Concordance between paired scans (MIBG, and PET) was found in 55.7% of cases (Kappa=0.001) for primary tumor site, and in 7% for bone and 19.4% for bone marrow. The significance of concordance between both modalities was only demonstrated for metastatic boney lesions. There were 13 patients having stage III neuroblastoma (43.3%) while 17 patients (56.7%) were having stage IV disease. 23 Patients were categorized as high risk (76.7%) while 7 patients (23.3%) were intermediate risk. Both, PET/CT scan and MIBG were more sensitive in detecting disease at stage IV than stage III.

Conclusion: ¹⁸F-FDG/PET scan can be used effectively in both diagnosis and management decisions for children with neuroblastoma, it is a good complementary tool especially in detecting bone metastasis, although further clinical trials must agree on definite analytical aspects between both modalities.