The use of both diagnostic and therapeutic MIBG in neuroblastoma patients

Neuroblastoma is the most common extra-cranial malignant solid tumour of childhood. It is an embryonic tumour derived from the sympathetic adrenal lineage of the neural crest. Distant metastases are present at diagnosis in 50% of the patients.
Metaiodobenzylguanidine (MIBG) is a compound structurally analogous to the neurotransmitter norepinephrine and is actively taken up in neuroendocrine cells. Labelled with radioactive iodine (123I or 131I), MIBG scintigraphy can be used for imaging and therapy of neuroblastoma. This thesis describes the use of MIBG in neuroblastoma patients as diagnostic and as therapeutic agent.
123I-MIBG scintigraphy proved to be a sensitive method to detect neuroblastoma and its metastases (pooled mean sensitivity of 92.4%, specificity of 85%).
No general conclusions could be drawn on the diagnostic accuracy to detect bone and bone marrow metastases, because definitions of bone and bone marrow metastases on imaging techniques were not uniformly reported and the sensitivity and specificity to detect bone and bone marrow metastases varied widely.
At diagnosis, patients with stage 4 neuroblastoma presented with two prognostically relevant MIBG-avid metastatic patterns: a "limited and focal" pattern mainly in MYCN-amplified neuroblastomas; and an "extensive and diffuse" pattern predominant in MYCN single copy neuroblastoma.
131I-MIBG therapy was effective for unresectable localised neuroblastoma causing or in danger of causing organ or respiratory dysfunction and offered a good alternative to chemotherapy if urgent treatment was needed. Upfront 131I-MIBG therapy caused only little toxicity in patients with newly diagnosed neuroblastoma. The most frequently encountered acute toxicity was haematological, followed by nausea and vomiting.