The Patterns of Cervical Lymph Node Metastasis and Risk Factors of Retropharyngeal Lymph Node Metastasis Based on MR Imaging in Different Sites of Hypopharyngeal Carcinoma

Abstract

This study aimed to determine the patterns of regional lymph node (LN) spread and the risk factors of retropharyngeal lymph node (RPLN) metastasis based on magnetic resonance imaging (MRI) in hypopharyngeal squamous carcinoma (HPC), to improve clinical target volume (CTV) delineation. A cohort of 326 consecutive patients of HPC were retrospectively reviewed. All patients got available MR imaging before they received definitive radiation therapy or surgery. The rate of LN metastasis was 90.5% (295/326). Level IIa/b and level III were the most frequently involved regions followed by level IV and retropharyngeal region. Skip metastasis occurred in only 6.4% (19/295). Univariate and multivariate analyses demonstrated that primary tumor subsites (p=0.002), bilateral cervical lymph node metastasis(p=0.020), GTVp (p=0.003) and GTVnd (p=0.023) were significantly associated with RPLN metastasis. Regional LN spread follow an orderly pattern as Level II was the most frequently involved followed by level III and RPLN in hypopharyngeal carcinoma. RPLN metastasis was more likely occur in patients with primary site of posterior pharyngeal wall, large tumor burden, and bilateral neck LN metastasis.