Efficacy of post‐induction therapy for high‐risk neuroblastoma patients with end‐induction residual disease

BACKGROUND High‐risk neuroblastoma patients with end‐induction residual disease commonly receive post‐induction therapy in an effort to increase survival by improving the response before autologous stem cell transplantation (ASCT). The authors conducted a multicenter, retrospective study to investigate the efficacy of this approach. METHODS Patients diagnosed between 2008 and 2018 without progressive disease with a partial response or worse at end‐induction were stratified according to the post‐induction treatment: 1) no additional therapy before ASCT (cohort 1), 2) post‐induction “bridge” therapy before ASCT (cohort 2), and 3) post‐induction therapy without ASCT (cohort 3). χ2 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 the end‐induction response was better for cohort 1 than cohorts 2 and 3, the outcomes for cohorts 1 and 2 were not significantly different (P = .77 for EFS and P = .85 for OS). Inferior outcomes were observed for cohort 3 (P < .001 for EFS and P = .06 for OS). Among patients with end‐induction stable metastatic disease, 3‐year EFS was significantly improved for cohort 2 versus cohort 1 (P = .04). Cohort 3 patients with a complete response at metastatic sites after post‐induction therapy had significantly better 3‐year EFS than those with residual metastatic disease (P = .01). CONCLUSIONS Prospective studies to confirm the benefits of bridge treatment and the prognostic significance of metastatic response observed in this study are warranted.