OP134: Pattern of cervical lymph node metastasis in medial wall pyriform sinus carcinoma: When do contralateral and paratracheal node dissection necessary?

Abstract

The aim of this study was to analyze the prevalence and distribution of histologic cervical lymph node metastases in medial wall pyriform sinus squamous cell carcinoma (SCC). Sixty-eight medial wall pyriform sinus SCC patients were retrospectively analyzed in this study. All patients underwent bilateral therapeutic/elective neck dissection. Thirty-nine patients underwent central compartment neck dissection. Eleven patients underwent retropharyngeal lymph node (RPLN) dissection. Primary tumor was removed using conservative laryngeal surgery with partial pharyngectomy in 39 cases, near total/total laryngectomy with partial pharyngectomy in 24 cases, and total laryngopharyngectomy in five patients. The overall N-positive contralateral lymph nodes rate on pathology was 14.7%. The rate of contralateral occult cases was 5.2%. Contralateral nodal metastasis was not significantly associated with disease-specific survival. Multivariate analysis revealed that primary lesion across the midline was an independent factor for contralateral neck nodal metastasis. The rate of level VI node metastasis was 16.2%. The disease-specific survival rate was significantly different according to level VI node metastasis (71% vs 40%). In multivariate analysis, pyriform sinus apex invasion was an independent factor for level VI nodal metastasis. RPLN metastasis was confirmed by pathological analysis in two of the 11 (18.2%) subjects. Contralateral nodal metastasis was less frequent than expected. Bilateral neck dissection is mandatory for primary lesion across the midline. Ipsilateral level VI lymph node should be removed in pyriform sinus apex invasion case. We recommend elective RPLN dissection in case with posterior pharyngeal wall invasion.