Prognostic value of retropharyngeal node involvement in CT-based lymph node-positive pharyngeal cancer following radiotherapy.

BACKGROUND The objective of this study was to evaluate the impact of metastasis to the retropharyngeal nodes (RPN) in CT-based lymph node-positive head and neck patients by comparing other node levels. PATIENTS AND METHODS A total of 175 CT-based lymph node-positive patients with carcinoma of the head and neck were managed with definitive radiation therapy. RPN involvement was identified only in pharyngeal cancer. One hundred and twenty-seven patients were investigated using CT and MRI following the guidelines on CT-based elective nodal delineation. Fifty-two patients received induction chemotherapy and 58 received concurrent chemoradiotherapy. RESULTS RPN involvement and lymph node size were identified as having a significant effect on the disease-free survival (DFS) in univariate analysis. Concurrent chemotherapy and RPN involvement significantly affected DFS on multivariate analysis in all pharyngeal cancer patients and non-nasopharyngeal cancer (NNP) patients. RPN involvement, level IV involvement and concurrent chemotherapy also significantly affected locoregional control. CONCLUSION Our study confirmed a poor outcome was associated with RPN involvement in patients with CT-based node-positive pharyngeal cancer and NNP patients definitively treated by radiotherapy.