Local Control With 21-Gy Radiation Therapy for High-Risk Neuroblastoma

Abstract

To evaluate local control after 21-Gy radiation therapy (RT) to the primary site in patients with high-risk neuroblastoma. After receiving dose-intensive chemotherapy and gross total resection (GTR), 246 patients (aged 1.2-17.9years, median 4.0years) with high-risk neuroblastoma underwent RT to the primary site at Memorial Sloan Kettering from 2000 to 2014. Radiation therapy consisted of 21Gy in twice-daily fractions of 1.5Gy each. Local failure (LF) was correlated with biologic prognostic factors and clinical findings at the time of diagnosis and start of RT. Median follow-up of surviving patients was 6.4years. Cumulative incidence of LF was 7.1% at 2years after RT and 9.8% at 5years after RT. The isolated LF rate was 3.0%. Eighty-six percent of all local failures were within the RT field. Local control was worse in patients who required more than 1 surgical resection to achieve GTR (22.4% vs 8.3%, P=.01). There was also a trend toward inferior local control with MYCN-amplified tumors or serum lactate dehydrogenase ≥1500 U/L (P=.09 and P=.06, respectively). After intensive chemotherapy and maximal surgical debulking, hyperfractionated RT with 21Gy in high-risk neuroblastoma results in excellent local control. Given the young patient age, concern for late effects, and local control >90%, dose reduction may be appropriate for patients without MYCN amplification who achieve GTR.