BACKGROUND: Diagnostic mIBG (meta-iodobenzylguanidine) scans are an integral component of response assessment in children with high-risk neuroblastoma. The role of end of induction (EOI) Curie Scores (CS) was previously described in patients undergoing a single autologous hematopoietic cell transplant (AHCT) as consolidation therapy. OBJECTIVE: We now examine the prognostic significance of CS in patients randomized to tandem AHCT on the Children’s Oncology Group (COG) trial ANBL0532. STUDY DESIGN: A retrospective analysis of mIBG scans obtained from patients enrolled in COG ANBL0532 was performed. Evaluable patients had mIBG-avid, International Neuroblastoma Staging System (INSS) stage 4 disease, did not progress during induction therapy, consented to consolidation randomization, and received a tandem AHCT (n=80). Optimal CS cut points maximized the outcome difference (≤ vs >CS cut-off) according to the Youden index. RESULTS: For recipients of tandem AHCT, the optimal cut point at diagnosis was CS=12, with superior EFS from study enrollment for patients with CS<12 (3-year EFS 74.2±7.9%) vs CS>12 (59.2±7.1%) (p=0.002). At EOI, the optimal cut point was CS=0, with superior end-induction EFS for patients with CS=0 (72.9±6.4%) vs CS>0 (46.5±9.1%) (p=0.002). CONCLUSION: In the setting of tandem transplantation for children with high-risk neuroblastoma, Curie scores at diagnosis and end-induction may identify a more favorable patient group. Patients treated with tandem AHCT who exhibited a CS<12 at diagnosis or CS=0 at EOI had superior EFS compared to those with CS above these cut points.
