Objectives: To report long-term results of primary radiotherapy for nasopharyngeal cancer (NPC) presenting in the adolescent group.
Methods: Ten adolescent patients with World Health Organization (WHO) type III NPC were treated with primary radiotherapy at our institution between 1969 and 2007. Median age was 16.5 years (range, 11 to 21). Median radiotherapy dose to the primary target volume was 67.5 Gy (range, 60 to 74.8). The bilateral neck received 51.1 Gy (range, 50 to 60 Gy). Five patients were treated with once-daily radiotherapy and 5 received twice-daily radiotherapy. Three patients received neoadjuvant cisplatin and 5FU, and 1 patient received adjuvant maintenance cisplatin and 5FU.
Results: Median follow-up time was 9.5 years (range, 1.94 to 34.74). Fifteen-year overall survival, cause-specific survival, and progression-free survival rates were all 70%. Fifteen-year local and regional control rates were 100% and 90%. One patient recurred regionally and distantly simultaneously, and 2 patients developed distant metastases alone. All 3 died of their disease within 3 years. One patient died from multiple radiation-induced secondary meningiomas 34 years after radiotherapy. Five patients developed hypothyroidism, 3 developed sensorineural hearing loss, and 4 developed dental complications. The overall rates of CTCAE grade 3, 4, and 5 toxicity were 40%, 10%, and 10%, respectively. Despite high-radiation doses to the skull base, none of the patients in this study developed grade 3+ cognitive or vision toxicity.
Conclusions: Radiotherapy achieves excellent local control in adolescent patients with unresectable WHO type III NPC. Our data support current protocols to systematically tailor treatment volumes and deescalate radiation doses to reduce treatment toxicity.