Salvage rates after progression of high-risk neuroblastoma with a soft tissue mass.

PURPOSE: Treatment of progression in high-risk neuroblastoma remains challenging despite improved survival. We retrospectively evaluated outcomes in children with a first progression that included soft-tissue masses. METHODS: We reviewed records of 903 consecutive children with high-risk neuroblastoma diagnosed between 2004 and 2014, and identified 42 whose first progression included soft-tissue masses. Data on demographics, disease characteristics, treatment, and survival were collected. Primary outcome was 5-year overall survival (OS) from time of first progression. Secondary outcomes were local disease-free progression (LDFR) and progression-free survival (PFS) postprogression. We evaluated the prognostic significance of concomitant bone/bone marrow involvement, MYCN status, and multifocality of soft tissue relapse. RESULTS: Median age at diagnosis was 3.0 (range: 1-10.7) years. Median time to first relapse or progression was 1.2 (range: 0.1-4.5) years after complete remission or minimal stable residual disease. Twelve (29%) patients had concomitant bone or marrow involvement at progression/relapse. There were 11 (26%) patients with International Neuroblastoma Staging System stage 3 disease (all with MYCN amplification), and 31 (74%) with stage 4 disease (12 with MYCN amplification). Nine (21%) patients had multifocal soft tissue progression. R1 resection was achieved in 41 children (95%), 38 (95%) of whom also received salvage radiation therapy. Five-year OS postprogression was 35% (95% CI: 19-51%), 5-year LDFS was 52% (95% CI: 32-72%), and 5-year PFS postprogression was 20% (95% CI: 6-34%). CONCLUSION: Among children with high-risk neuroblastoma who underwent aggressive treatment of a first soft-tissue recurrence, 5-year postprogression overall survival was 34%. Multifocality and MYCN amplification were the predominant prognostic correlates for worse survival.