Intra-operative radiation therapy in pediatric neuroblastoma.

External beam irradiation (EBRT) has been shown to improve response rates and event-free survival in children with neuroblastoma and regional lymph node metastases. Irradiation during surgical exposure (intra-operative radiotherapy, IORT) with displacement of adjacent radiosensitive organs out of the treatment field allows for more precise delineation of the target volume and significantly reduces the amount of normal tissue exposed to irradiation. We have incorporated IORT into the treatment regimen of 24 children with neuroblastoma between the years of 1983-1991. IORT was directed to any residual tumor or the tumor bed; the median dose of radiation was 1,000 cGY, equivalent to 3,000 cGY of conventional EBRT. There were 11 males and 13 females. Two patients had stage II, 12 patients had stage III, and 10 patients had stage IV disease. Ten children received IORT for suspected recurrent or persistent neuroblastoma. Twelve patients were disease-free survivors following IORT with a median follow-up of 54 months. For those patients with stage III disease, seven children were disease-free survivors, while only three of 10 patients with stage IV disease survived (median follow-up 30 months). Disease-free Survival (DFS) correlated with the achievement of local tumor control in children with both stage III and IV neuroblastoma. There was limited morbidity and no episodes of obstructive uropathy were encountered. We conclude that IORT appears to be well tolerated and may have therapeutic benefit for a select group of patients with neuroblastoma. IORT merits future exploration by prospective study.