Nasopharyngeal carcinomas (NPCs) are malignant tumors which exhibit a wide disparity in their age, racial, and geographic incidence. In parts of Africa NPCs account for 10% to 20% of childhood malignancies. In USA and Europe, the NCP is an uncommon tumor (0.2% of all malignancies) and amounts to only 1% to 2% of childhood malignancies. Etiology and pathogenesis are closely related to an infection with Epstein-Barr Virus (EBV) and the EBV genome was detected in tumor tissues. Children with NPC differ from their adult counterparts in having a closer association with Epstein-Barr-Virus-Infections. The classical lymphoepithelial carcinomas (Cologne type II-type III) have been found in young patients. Clinically, the disease is aggressive, characterised by frequent metastases in bone and lung. These carcinomas are associated with significantly elevated anti-EBV-titers. The prognosis of children with advanced NPC is poor with a 5-year survival rate between 20-30%. Radiotherapy is the treatment of choice in NPC which has provided an improvement in local tumor control in recent years. Human fibroblast interferon is an active agent in recurrent NPC. Seven children have been treated with IFN-beta, (6 with human und 1 with recombinant IFN-beta) as an adjuvant therapy in doses of 10(5) U/kg body weight three times a week for half a year. All patients received radiotherapy to primary site and had advanced stages (III-IV) at presentation. The patients' age ranged from 14-19 years at diagnosis. Six are still in CR (RFS are 10, 8, 8, 7, 6 and 1.5 years) and one patient relapsed after 18 months.(ABSTRACT TRUNCATED AT 250 WORDS)