Dose Escalation is Needed for Gross Disease in High-Risk Neuroblastoma

Abstract

Loco-regional failure is common after subtotal resection in high-risk neuroblastoma. Although a dose of 21 Gy 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 21-36 Gy RT in patients with high-risk neuroblastoma undergoing subtotal resection. All patients with high-risk neuroblastoma who received RT to their primary site at a single institution 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 had gross disease at the primary site at the time of RT. Local failure (LF) was correlated with biologic prognostic factors and dose of RT. Median follow-up of surviving patients was 5.9 years. Median RT dose was 25 Gy (range, 21 Gy - 36 Gy). The 5-year cumulative incidence of LF among all patients was 19%. LF at 5 years was 35.7% in those who received <30 Gy, 20% in those who received 30 Gy, and 0% in those who received 36 Gy. MYC-N amplification was associated with worse local control (LF was 33.3% in those with MYC-N amplification vs. 11.4% in those without). The 5-year event-free and overall survival were 46.4% and 66%, respectively. After subtotal resection, patients who received 30 Gy or less had poor local control. Doses of 36 Gy are likely needed for optimal control of gross residual disease at the time of consolidative RT in high-risk neuroblastoma.