Analysis of clinical efficacy and safety of local radiotherapy in children with stage IV high-risk neuroblastoma

Abstract

Objective To retrospectively analyze the clinical efficacy, safety and influencing factors of radiotherapy in children with stage Ⅳ high-risk neuroblastoma (HR-NB). Methods A total of 120 children with HR-NB who were diagnosed and treated with local radiotherapy according to the BCH-HR-NB-2007 protocol in the Oncology Department of Beijing Children′s Hospital from January 2014 to December 2017 were enrolled. Among them, 56 children were male and 64 female with a median age of 43 months (9-148 months). The treatment protocol consisted of 4 cycles of CAV chemotherapy, 3 cycles of CVP chemotherapy, surgical resection after 4 cycles, autologous hematopoietic stem cell transplantation after 7 cycles, local radiotherapy at a dose of 15.0-30.6 Gy for 82 cases of primary tumors and 38 cases of primary and metastatic tumors, followed by 13 cis-retinoic acid as maintenance therapy. The entire treatment protocol endured for approximately 18 months. Results The median follow-up time was 21 months. The 3-year local control rate was 84.4%. Before radiotherapy, the 3-year event-free survival rate was 78.4% in children without metastases, significantly higher compared with 30.4% in the residual group (P=0.003). The 3-year event-free survival rate was 66.1% in patients who underwent radiotherapy within 6 months after surgery, significantly higher than 50.6% in their counterparts receiving radiotherapy at 6 months or more after surgery (P=0.018). Among the children with residual metastases before radiotherapy, the progression rate in children who did not receive radiotherapy was 66.6%, significantly higher compared with 20.0% in those receiving radiotherapy (P=0.001). All patients had no radiation-related adverse reactions in the liver, kidney and heart, etc. The incidence rate of grade Ⅲ-IV myelosupression was 24.5% at 1 week post-radiotherapy, and 8% at 2 weeks after radiotherapy. Conclusions Radiotherapy yields definite clinical efficacy in the local control of children with stage Ⅳ HR-NB. Early radiotherapy after surgery and radiotherapy for the metastatic lesions can improve the clinical prognosis. No vital organ injuries are observed during the short-term follow-up. At 2 weeks after radiotherapy, the myelosupression is gradually restored. Key words: Neuroblastoma/radiotherapy; Neuroblastoma/chemotherapy; Prognosis