Background: This study aimed to determine the incidence, risk factors, and prognostic significance of retropharyngeal lymph node (RPLN) metastasis from malignancies of the oropharynx.
Methods: The study retrospectively analyzed 54 patients with oropharyngeal squamous cell carcinoma who underwent primary surgery-based treatment. Most of the patients had advanced stage (stage 3 or 4, 96.3 %) oropharyngeal cancer. Surgery alone was performed for 14 patients. Postoperative radiotherapy was administered to 14 patients and chemoradiation to 26 patients. Genotyping and detection of human papillomavirus (HPV) was available for 52 patients.
Results: Using pathologic analysis, RPLN metastasis was confirmed in 22 subjects. The patients with RPLN metastasis had a significantly lower disease-specific survival rate than the non-RPLN metastasis group (54.5 vs 75 %; p = 0.05). The pN+ (RPLN) yield of these cases was 18/22 (81.8 %) for cN+ (RPLN) versus 4/32 (7.4 %) for cN0 (RPLN). Multivariate analysis identified the independent factors associated with RPLN metastasis as radiographically positive retropharyngeal node (p = 0.012; odds ratio [OR] 53.920) and posterior pharyngeal wall invasion (p = 0.021; OR 33.014). A high-risk HPV-positive result was not significantly correlated with RPLN metastasis.
Conclusions: Elective RPLN dissection should be considered for patients with advanced neck and primary tumor, particularly those with posterior pharyngeal wall invasion.