Efficacy of Post-Induction Therapy for High-risk Neuroblastoma Patients with End-Induction Residual Disease

Abstract

Background: High-risk neuroblastoma patients with end-induction residual disease commonly receive post-induction therapy in an effort to increase survival by improving response prior to autologous stem cell transplant (ASCT). We conducted a multi-center, retrospective study to investigate the efficacy of this approach. Methods: Patients diagnosed between 2008 and 2018 without progressive disease (PD) with ≤ partial response (PR) at end-induction were stratified according to post-induction treatment: i) no additional therapy prior to ASCT (Cohort 1); ii) post-induction “bridge” therapy prior to ASCT (Cohort 2); and iii) post-induction therapy without ASCT (Cohort 3). Chi-square tests were used to compare patient characteristics. Three-year event-free survival (EFS) and overall survival (OS) were estimated by the Kaplan-Meier method and survival curves were compared by log-rank test. Results: The study cohort consisted of 201 patients; Cohort 1 (n=123); Cohort 2 (n=51); and Cohort 3 (n=27). Although end-induction response was better for Cohort 1 than Cohorts 2 and 3, outcome for Cohort 1 and 2 was not significantly different (EFS; p=0.77 and OS; p=0.85). Inferior outcome was observed for Cohort 3 (EFS; p<0.001 and OS; p=0.06). Among patients with end-induction stable metastatic disease, 3-year EFS was significantly improved for Cohort 2 compared to Cohort 1 (p=0.04). Cohort 3 patients with complete response (CR) in metastatic sites following post-induction therapy had significantly better 3-year EFS compared to those with residual metastatic disease (p=0.01). Conclusions: Prospective studies to confirm the benefits of bridge treatment and the prognostic significance of metastatic response observed in this study are warranted.