Efficacy of intensity-modulated radiotherapy combined with chemotherapy for nasopharyngeal carcinoma in children and adolescents

Objective: To evaluate the treatment outcomes and toxicities of intensity-modulated radiation therapy (IMRT) combined with chemotherapy for children and adolescents with nasopharyngeal carcinoma. Methods: Forty-three nasopharyngeal carcinoma patients less than 19 years old were recruited between April 2010 and April 2016. All patients were treated with IMRT (total dose 61.2-76 Gy) combined with cisplatin based chemotherapy. The Kaplan-Meier test was used to calculate overall survival (OS) and progression-free survival (PFS). The patient's clinical characteristics, side effects and long-term effects of treatment were retrospectively analyzed. Results: Among 43 patients, there were 29 (67.4%) male and 14 (32.6%) female, and the median age was 14 years old (range, 6-18 years). According to AJCC 7^th staging system, 2 patients were in stage Ⅱ, 26 in stage Ⅲ, 7 in stage Ⅳ_A and 8 in stage Ⅳ_B. All patients were confirmed as non-keratinizing carcinoma. The positive rates of EB virus VCA-IgA was 53.8% (7/13), and Rta-IgG was 60.0% (6/10) before treatment. The median radiation dose was 70 Gy (range, 61.2-76 Gy) to the primary tumor. Thirty-three (76.7%) patients received neoadjuvant chemotherapy, with 20 (46.5%) and 36 (83.7%) patients treated by concurrent and adjuvant chemotherapy, respectively. With a median follow-up of 24 months (range, 3-76 months), the 5-year OS and PFS ratios were 75.3% and 64.7%, respectively. There were 5 patients (11.6%) occured to bone metastasis within 2 years after treatment. Hypothyroidism was reported in 47.4% (9/19) patients after IMRT. Conclusions: Nasopharyngeal carcinoma in childhood and adolescence is mostly locally advanced diseases with poor differentiation. IMRT combined with chemotherapy produce a well treatment outcome with good tolerance in children and adolescents patients. The most common treatment failure bone metastasis. Radiation-induced hypothyroidism is common. (authors)