Involvement of both Cervical Lymph Nodes and Retropharyngeal Lymph Nodes has prognostic value for N1 patients with Nasopharyngeal Carcinoma

BACKGROUND: The N1 definition of 2010 UICC/AJCC staging system for nasopharyngeal carcinoma (NPC) covers quite a large range of nodal pattern. The objective of this research is to investigate prognostic value of lymph nodes related factors including involvement of both cervical lymph nodes (CLNs) and retropharyngeal lymph nodes (RLNs) or not, size and number of cervical lymph nodes (CLNs) in N1 patients with NPC. METHODS: 142 newly diagnosed non-metastatic N1 patients with NPC, staged according to the 2010 AJCC staging system for NPC were retrospectively enrolled. All patients had undergone contrast-enhanced magnetic resonance imaging (MRI), and received radiotherapy, with or without chemotherapy as their primary treatment. RESULTS: The median follow-up was 48 months. The 5-year local recurrence-free survival (LFS), nodal recurrence-free survival (NFS), local-regional recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), progression-free survival (PFS), and overall survival (OS) of the whole group were 82.3%, 83.0%, 81.0%, 82.1%, 75.3% and 89.8%, respectively. In univariate analysis, patients with both CLNs and RLNs involvement showed a significant lower DMFS, PFS and LRFS than the rest patients (p = 0.004 p = 0.003 and p = 0.034, respectively). Neither size nor number of CLNs affected the survival. In multivariate analysis, involvement of both CLNs and RLNs was an independent prognostic factor for DMFS and PFS (p = 0.019, p = 0.019), but there was no enough evidence confirming its prognostic value for LRFS (p = 0.051). CONCLUSIONS: For N1 patients with NPC, involvement of both RLNs and CLNs may be a potentially prognostic factor for distant metastasis and disease progression. The N stage for N1 patients with involvement of both cervical lymph nodes and retropharyngeal lymph nodes might need to be deliberated.