T4/N2 classification nasopharyngeal carcinoma benefit from concurrent chemotherapy in the era of intensity-modulated radiotherapy.

Although the benefits of concurrent chemotherapy (CC) in the treatment of locally advanced nasopharyngeal carcinoma (NPC) had been proven in the era of two-dimensional radiotherapy, long-term efficacy and safety of using CC combined with intensity-modulated radiotherapy (IMRT) remain unclear. A retrospective analysis of 1,182 patients who underwent IMRT for clinical II-Iva NPC was performed. Propensity score matching algorithm was used to identify two matched cohorts with or without CC (264 patients per cohort). Median follow-up time was 45.6 and 43.6 months for the two cohorts. The estimated 5-year overall survival rate was 81.8% (95% CI 76.6-87.4) in patients treated with CC and 73.7% (95% CI 67.8-80.0) in those treated without CC, respectively (hazard ratio 0.64, 95% CI 0.44-0.93; p = 0.018). The benefit of CC was mainly observed in those patients with good performance status, male, age > 48 years, T4 and N2 classification. Grade 3/4 acute toxicities were more common in those patients administrated with CC. The grade and incidence of late salivary glands damage were also increased by CC (p = 0.003). These findings indicated that the addition of CC significantly improved treatment outcomes of NPC patients treated with IMRT, but accompanied increased toxicities. Tailored CC and optimizing schedule of IMRT and systemic therapy were needed, provided that distant metastasis was the predominant pattern of failure in patients treated with IMRT.