INTRAOPERATIVE RADIATION-THERAPY IN PEDIATRIC NEUROBLASTOMA

External beam irradiation (EBRT) has been shown to improve response ra tes and event-free survival in children with neuroblastoma and regiona l lymph node metastases. Irradiation during surgical exposure (intra-o perative radiotherapy, IORT) with displacement of adjacent radiosensit ive organs out of the treatment field allows for more precise delineat ion of the target volume and significantly reduces the amount of norma l tissue exposed to irradiation. We have incorporated IORT into the tr eatment regimen of 24 children with neuroblastoma between the years 19 83-1991. 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 co nventional EBRT. There were 11 males and 13 females. Two patients had stage II, 12 patients had stage III, and 10 patients had stage IV dise ase. Ten children received IORT for suspected recurrent or persistent neuroblastoma. Twelve patients were disease-free survivors following I ORT with a median follow-up of 54 months. For those patients with Stag e 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 achievemen t of local tumor control in children with both stage III and IV neurob lastoma. There was limited morbidity and no episodes of obstructive ur opathy were encountered. We conclude that IORT appears to be well tole rated and may have therapeutic benefit for a select group of patients with neuroblastoma. IORT merits future exploration by prospective stud y. (C) 1997 Wiley-Liss, Inc.