Chemoradiotherapy in Children with Undifferentiated Nasopharyngeal Carcinoma

Abstract

Undifferentiated nasopharyngeal carcinoma (UNC) differs from other epithelial tumors of the head and neck by a close connection with lymphatic tissue, epidemiology, and biological characteristics that determine the clinical course of the disease and therapeutic approaches. In this histological variant, a high titer of antibodies to the Epstein–Barr virus (EBV) was observed in blood of 100% of patients. Absence of specific symptoms, polymorphic clinical picture, and latent disease course lead to the detection of a tumor in children only at stages III–IV. Radiotherapy (RT), as the only method for the treatment of UNC, has been used for almost 30 years in all age groups of patients regardless of the disease stage. In most studies, 1.8–2 Gy per day and 50–70 Gy per course were applied to irradiate the nasopharynx and the affected lymph nodes. Modern treatment protocols require the use of conformal irradiation using magnetic resonance imaging (MRI) and computer tomography (CT) with contrast enhancement to form a three-dimensional model of RT planning. High efficacy and a radiosensitive effect were observed when platinum-based antineoplastic drugs were administered. The chemotherapy (CTx) regimens for pediatric patients included cisplatin, cyclophosphamide, and methotrexat which were administered both before and after RT. Maintenance therapy with interferon-β also positively affected the treatment results. Combined approaches allowed to increase the level of five-year overall survival rate up to 70–90%. The analysis of complications and long-term treatment effects in children with UNC showed a significant effect of total focal dose and irradiation technique on early radiation reactions from local tissues in the form of dermatitis, mucositis, and xerostomia, as well as on delayed radiation complications and development of second tumors. The review demonstrates the main therapeutic approaches to the treatment of children with UNC both in the historical aspect and according to current trends.