Semiquantitative mIBG scoring as a prognostic indicator in patients with stage 4 neuroblastoma: a report from the Children's oncology group

Abstract

Radiolabeled metaiodobenzylguanidine (mIBG) is a highly sensitive and specific marker for detecting neuroblastoma. A semiquantitative mIBG score (Curie score [CS]) was assessed for utility as a prognostic indicator for a cohort of patients with high-risk metastatic disease. METHODS: mIBG scans from 280 patients with mIBG-avid, stage 4 neuroblastoma enrolled on the Children's Oncology Group (COG) protocol A3973 were evaluated at diagnosis (n = 280), after induction chemotherapy (n = 237), and after an autologous stem cell transplantation (n = 178). Individual mIBG scans were evaluated at 10 different anatomic regions, with the scoring of each site (0-3) based on the extent of disease at that anatomic region. RESULTS: There was no correlation between CS at diagnosis and subsequent treatment outcome. Patients with a CS > 2 after induction therapy had a significantly worse event-free survival (EFS) than those with scores 2 identified a cohort of patients at greater risk for an event, independent of other known neuroblastoma factors, including age, MYCN status, ploidy, mitosis-karyorrhexis index, and histologic grade. For MYCN-amplified tumors, the presence (CS > 0) versus absence (CS = 0) of residual mIBG avidity after induction was associated with a significantly worse outcome (3-y EFS: 11.8% +/- 7.8% vs. 49.6% +/- 7.7%, respectively; P = 0.003). After transplantation, patients with a CS > 0 had an EFS inferior to that of patients with a CS of 0 (3-y EFS: 28.9% +/- 6.8% vs. 49.3% +/- 4.9%, respectively [n = 133]; P = 0.009). CONCLUSION: Curie scoring carries prognostic significance in the management of patients with high-risk neuroblastoma. In particular, patients with CSs > 2 after induction have extremely poor outcomes and should be considered for alternative therapeutic strategies.