Nuclear medicine procedures and neuroblastoma in childhood. Their value in the diagnosis, staging and assessment of response to therapy.

Neuroblastoma is a frequent tumor of childhood and remains a leading cause of death despite treatment intensification. Many clinical, biological and genetic factors have been identified and are associated with prognosis and outcome after treatment. Initial staging plays a major role for determining the therapeutic strategy. Radioiodinated metaiodobenzylguanidine (MIBG) scintigraphy is a highly sensitive and specific method for diagnosing, staging and also monitoring response to therapy. In children with high-risk neuroblastoma, relapse may occur any time after remission has been obtained. (123)I-MIBG scintigraphy is a reliable method to follow-up those children and allows early detection of recurrence. As far as outcome is concerned, MIBG scintigraphy has not proven to have any prognostic value. Other radiolabeled tracers, such as pentetreotide, monoclonal antibodies, and sestamibi have been compared with MIBG. Up to now, no method has demonstrated a reliable prognostic value, even though neuroblastoma that express somatostatin receptor seem to have a better clinical outcome and survival rate. Positron emission tomography (PET) with (18)F-fluorodeoxyglucose has been used successfully in staging and monitoring response to treatment of MIBG negative tumors. (11)C-hydroxyephedrine has shown promising results in staging neuroblastoma, but is not as widely available as MIBG. With respect to biological and genetic factors, nuclear medicine procedures play a major role in initial diagnosis and staging of neuroblastoma. At the moment, MIBG scintigraphy is certainly the most sensitive and specific method for initial staging of the disease, as well as monitoring the response to treatment and detecting early relapse.