Scintigraphic Response by 123I-Metaiodobenzylguanidine Scan Correlates With Event-Free Survival in High-Risk Neuroblastoma

Abstract

Purpose To investigate whether response to induction therapy, evaluated by metaiodobenzylguanadine (MIBG) and bone scintigraphy, correlates with event-free survival (EFS) in children with high-risk neuroblastoma (NB). Patients and Methods Twenty-nine high-risk NB patients were treated prospectively with an intensive induction regimen and consolidated with three cycles of high-dose therapy with peripheral blood stem-cell rescue. The scintigraphic response was evaluated by MIBG and bone scans using a semi-quantitative scoring system. The prognostic significance of the imaging scores at diagnosis and following induction therapy was evaluated. Results A trend associating worse 4-year EFS rates for patients with versus without osteomedullary uptake on MIBG scintigraphs at diagnosis was seen (35% ± 11% v 80% ± 18%, respectively; P = .13). Similarly, patients with positive bone scans at diagnosis had worse EFS than those with negative scans, although the difference did not receive statistical significance (34% ± 10% v 83% ± 15%, respectively; P = .06). However, significantly worse EFS was observed in patients with a postinduction MIBG score of ≥ 3 compared to those with scores of less than 3 (0% v 58% ± 11%; P = .002). There was no correlation between bone scan scores and outcome following induction therapy. Conclusion MIBG scores ≥ 3 following induction therapy identifies a subset of NB patients who are likely to relapse following three cycles of high-dose therapy with peripheral blood stem-cell rescue, local radiotherapy, and 13-cis-retinoic acid. Alternative therapeutic strategies should be considered for patients with a poor response to induction therapy.