Intraoperative radiation therapy for high-risk pediatric neuroblastoma

PURPOSE: To evaluate the efficacy of intraoperative radiation therapy (IORT) in the treatment of high-risk pediatric neuroblastoma. METHODS AND MATERIALS: Between 1986 and 1998, 23 children received IORT for pediatric neuroblastoma. Electron beam energies ranged from 4 MeV to 16 MeV and median dose was 10 Gy (7-16 Gy). RESULTS: Twenty-one of 23 patients were classified as high-risk. A gross total resection (GTR) was achieved in 18 patients, of whom 6 experienced disease recurrence, 2 of which included a locoregional relapse as a component of failure. Fourteen of 18 patients receiving IORT after a GTR are disease-free survivors. A second subset of 5 patients had a subtotal resection (STR), with gross residual disease remaining after surgery. All 5 patients recurred locally, and all died of their disease. IORT was extremely well-tolerated in our cohort. Surgical resection and IORT resulted in the narrowing of the abdominal aorta and an atrophic kidney in 1 patient. CONCLUSIONS: For high-risk neuroblastoma patients, IORT as the only radiotherapy to the primary, produced excellent local control after a GTR. However, IORT as the sole radiotherapy to the primary was inadequate for patients with extensive adenopathy or an STR. In this setting, we are exploring the use of IORT as a boost in conjunction with external beam radiation therapy.