Introduction:
Neuroblastoma accounts for about 10% of all solid tumors in pediatric age group and is the most common extracranial solid tumor in pediatric age group1. It occurs in the neural crest derivatives and has a varied presentation ranging from self-resolving Stage 4S disease to the highly malignant variant associated with extremely poor prognosis2, 3. Staging evaluation of Neuroblastoma requires morphological imaging including Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) scans as well as nuclear medicine imaging to look for skeletal metastatic deposits4, 5.123I-Metaiodobenzylguanadine (MIBG) is a radiopharmaceutical structurally similar to norepinephrine that concentrates within secretory granules of catecholamine-producing neural crest cells. It can be used for localization of neural crest tumors such as Neuroblastoma, pheochromocytoma, and indeed other Neuro Endocrine Tumors anywhere in the body. It has been the standard for Neuroblastoma staging for 4 decades since its utility was first reported by Geatti et al in 1985 6, 7.
Reported sensitivity and specificity of 123I-MIBG is ~90%5, 8. However, as 10% of Neuroblastomas are MIBG non avid, alternate imaging techniques have been investigated including Positron emission tomography (PET) with 2-deoxy-2-[fluorine-18]fluoro-D-glucose (18F-FDG) and radiolabeled somatostatin analogues such as Octreotide, L-3,4-Dihydroxy-6-[18F]fluorophenylalanine (18F-DOPA) and 1,4,7,10-tetraazacyclotetradecane-N,N’,Nā€,Nā€ā€™ -tetraacetic acid (DOTA)-conjugated peptides including 68Ga- DOTATATE PET/CT. When combined with PET/CT or MRI, these modalities have been shown to be superior in sensitivity and specificity to MIBG thus having the potential of replacing MIBG9-12.
Somatostatin (SST) is a hypothalamic peptide that inhibits the secretion of pituitary growth hormone, pancreatic and gastric hormones. Somatostatin receptors (SSTR) are variably expressed in Neuroblastoma tumor cells13, 14. Somatostatin analogues such as DOTATATE have been in clinical use for nearly a decade. Their role is most established in imaging and treatment of adult neuroendocrine tumors (NET) and pheochromocytoma, but also studied in Neuroblastoma in limited settings10, 11. Role of 68Ga- DOTATATE PET/CT has been studied at the time of recurrence and at the therapeutic planning phase within a theranostics paradigm. However, there are very few reports of its role at diagnosis for staging8, 15.
As MIBG production is limited globally, the SARS-CoV-2 (COVID-19) pandemic has resulted in unacceptable delays in carrying out MIBG scans due to interruption in international air traffic. Its availability became particularly challenging at our institution, we therefore decided to perform 68Ga-DOTATATE PET/CT scans for three newly diagnosed patients with Neuroblastoma. This PET agent is locally produced in a nearby center obviating all the delivery logistics issues. Here we report our results with a review of the literature.