The Relationship Between The Retropharyngeal Node And The Prognosis Of Nasopharyngeal Carcinoma In The Intensity‐modulated Radiotherapy Era

Objective: The purpose of this study was to investigate the prognostic value of retropharyngeal lymphadenopathy for when patients were treated by intensity-modulated radiotherapy(IMRT).Materials and methods: A total of 1197 patients were retrospectively studied. All were staged by magnetic resonance imaging(MRI) and irradiated with IMRT. The prognostic value of the retropharyngeal node(RPN) and its characteristics including laterality, size, necrosis, horizontal level, extra-nodal neoplastic spread(ENS) were evaluated.Results: The incidence of RPN metastasis was 74.0%. The incidence of RPN and level II metastasis in 1027 cases with known neck node involvement were 86.3% and 81.6%, and were higher than group I(2.3%), III(21.1%), Va(8.4%), IV(5.8%), Vb(3.0%), respectively. Metastatic RPN and level II shared no significant differences in survival. RPN metastasis was an independent prognostic factor for distant failures(Hazard ratio(HR) = 1.615,95%CI=1.063~2.452, p=0.025). RPN laterality has significant impacts on both distant failure(p=0.006) and disease progression(p=0.001). In multivariate analyses, RPN laterality was an independent factor for progression-free survival(PFS)(HR=1.342, 95%CI: 1.066-1.834, P=0.015). In N1 disease, RPN laterality showed significant differences for disease free survival(DFS) and PFS(p=0.045 and 0.049, respectively). But for RPN metastasis only, laterality had similar survival curves. Moreover, the involvement of both bilateral RPN and cervical lymph node(CLN) was an independent adverse factor(P<0.01) for distant failure and disease progression except disease specific failure and loco-regional recurrence in N1 disease.Conclusion: Both RPN and level II are the first station of nasopharyngeal drainage. Not only RPN metastasis but also RPN laterality was considered as an important prognostic factor for NPC. In N1 stage, involvement of both bilateral RPN and CLN had an adverse influence for NPC patients and should arise our clinical attention. Further studies about RPN laterality, especially in N1 stage should be conducted. Key words:...