ABSTRACT
<p><b>OBJECTIVE</b>To investigate the clinicopathologic features and associated risk factors for bilateral neck node metastasis (BNM) in head and neck squamous cell carcinoma (HNSCC).</p><p><b>METHODS</b>Two hundred eighty-six cases with HNSCC were retrospectively studied, including 83 cases of oral tongue cancers, 101 cases of hypopharyngeal cancers and 102 cases of supraglottic laryngeal cancers. All patients had unilateral or bilateral cervical lymph node metastasis confirmed by postoperative pathologic examinations. The following factors were evaluated to determine the risk for BNM in HNSCC: T staging, size, location, trans-midline condition, growth pattern, pathologic grading and infiltration of primary tumors; N staging; the size, number and extracapsular spread (ECS) of ipsilateral metastatic nodes; the number of involved levels on the ipsilateral neck. Chi-square test and logistic regression test were used for statistical analysis.</p><p><b>RESULTS</b>BNM was found in 86 (30.1%) of 286 patients with HNSCC, including 52 (18.2%) cases of contralateral occult neck node metastasis. The incidence of BNM was 35.6% (36/101) in hypopharyngeal cancer, 31.4% (32/102) in supraglottic laryngeal cancer and 21.7% (18/83) in oral tongue cancer, respectively. N staging, the number and ECS of ipsilateral metastatic nodes, and the number of involved levels on the ipsilateral neck were important factors contributing to BNM. Multiple logistic regression analysis revealed that midline passing of primary tumor was associated with BNM in oral tongue cancer. The midline passing and ECS of ipsilateral metastatic node were key factors for BNM in hypopharyngeal and supraglottic laryngeal cancers. T staging, size and midline passing of primary tumor were closely related to BNM in oral tongue cancer. T staging and midline passing were associated with BNM in hypopharyngeal cancer. Midline passing was an important factor related to BNM in supraglottic laryngeal cancer.</p><p><b>CONCLUSION</b>Midline passing of primary tumor is the most important factor determining BNM in hypopharyngeal, supraglottic laryngeal and oral tongue cancers, whereas ECS of ipsilateral metastatic node is the most important factor impacting BNM in hypopharyngeal and supraglottic laryngeal cancers.</p>