Dose-escalation is needed for gross disease in high-risk neuroblastoma

BackgroundLocoregional failure is common after subtotal resection in high-risk neuroblastoma. Although a dose of 21Gy radiation therapy (RT) is standard for treatment of high-risk neuroblastoma after gross total resection, the dose needed for local control of patients with gross residual disease at the time of RT is unknown. We sought to evaluate local control after 21-36Gy RT in patients with high-risk neuroblastoma undergoing subtotal resection. MethodsAll patients with high-risk neuroblastoma who received RT to their primary site from 2000 to 2016 were reviewed. Of the 331 patients who received consolidative RT to their primary site, 19 (5.7%) underwent subtotal resection and were included in our analysis. Local failure (LF) was correlated with biologic prognostic factors and dose of RT. ResultsMedian follow-up among surviving patients was 6.0 years. Median RT dose was 25Gy (range, 21Gy-36Gy). The 5-year cumulative incidence of LF among all patients was 17.2%. LF at 5 years was 30% in those who received <30Gy versus 0% in those who received 30-36Gy (P=0.12). There was a trend towards improved local control in patients with tumor size 10cm at diagnosis (P=0.12). The 5-year event-free and overall survival were 44.9% and 68.7%, respectively. ConclusionAfter subtotal resection, patients who received less than 30Gy had poor local control. Doses of 30-36Gy are likely needed for optimal control of gross residual disease at the time of consolidative RT in high-risk neuroblastoma.