Is nasopharyngeal carcinoma in young patients a distinct clinical entity? A single-institution case matched analysis in the era of intensity-modulated radiotherapy

Objectives: To compare the treatment outcomes between young and adult patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT). Materials and methods: We conducted a retrospective case-matched analysis of all patients with non-metastatic NPC <= 20 years treated in our institution between January 2010 and July 2016. Adult patients >= 35 years treated over the same time period were included and matched at a ratio of 1:1 according to N classification, T classification, treatment modality, year of diagnosis, and gender. Survival outcomes and late toxicities were compared between the two groups. Results: Overall 112 young patients with NPC were included, and 112 out of 3105 consecutive patients with NPC aged >= 35 years were matched. The 5-year overall survival (OS), progression-free survival, locoregional control and distant control of young and control cohorts were 89.1% vs. 79.3% (p = 0.03), 80.3% vs. 67.0% (p = 0.02), 96.4% vs. 84.3% (p < 0.01), and 82.9% vs. 82.8% (p = 0.94), respectively. Multi-variate analysis showed that age <= 20 years was the only significant factor predicting for better OS (HR = 0.5, CI 0.3-0.97, p = 0.04). A trend of higher rate of hypothyroidism (grade 1-2) was observed in the young cohort (67.9% vs. 46.2%, p = 0.08). Conclusion: Young patients with NPC treated with modern multimodality therapy have better survival outcomes. Age was an independent favorable prognostic factor for NPC in the IMRT era. Further prospective studies are needed to establish optimal management for the young population to minimize and manage long-term sideeffects without compromising survival.