Objective. Metaiodobenzylguanidine (MIBG) scans were studied to determine the impact of the scan results on the clinical treatment of pediatric patients with neural crest tumors.
Methods. Serial scans were reviewed retrospectively for 27 patients with neural crest tumors: 25 with initial diagnoses of neuroblastoma (NB), 1 with ganglioneuroblastoma, and 1 with ganglioneuroma (GN). Results were compared with bone scans and computed tomography scans, as well as surgical pathologic findings.
Results. At initial diagnosis, when compared with bone and computed tomographic scans, MIBG imaging did not identify any unsuspected lesions that resulted in a change in staging. Thirteen patients with NB who had initially positive MIBG scan results had serial studies that normalized during therapy. However, after completion of therapy, 8 of 13 had relapses of the disease. Although areas of active disease were well delineated by other standard imaging modalities for all 8, only 4 (50%) had MIBG study results that were positive in sites of relapse. There were 4 cases of GN (1 at diagnosis and 3 after therapy for NB) demonstrating an uptake of MIBG that was similar in appearance to that in NB.
Conclusions. MIBG imaging did not change the staging or alter treatment during therapy for any patient. Normalization of positive study results was an unreliable indicator of outcome for children with NB. Furthermore, when relapse occurred, MIBG scans identified only 50% of those with active NB. The uptake of MIBG in GN was indistinguishable from that in NB. In this series, the results of serial MIBG studies did not have a significant impact on patient treatment.