Systematics in lymphatic tumor spread of carcinomas of the upper aerodigestive tract : a clinical study based on embryologic data

The aim of this study was to assess the incidence and pattern of cervical lymph node (LN) metastases in carcinomas of the upper aerodigestive tract in relation to primary tumor (PT) invasion of the equivalents of pharyngeal arches (PhA) and occipital and cervical somites (OCS) in adults. The pretherapeutic computed tomography scans and clinical findings in 729 patients with histologically proven carcinoma of the upper aerodigestive tract (112 nasopharyngeal, 289 oropharyngeal, 252 laryngo-hypopharyngeal, and 76 oral cavity carcinomas, with LN involvement in 70% of the total) were analyzed in relation to PT invasion of equivalents of PhA and OCS. Tumors were recorded according to the infiltration of these equivalents. The metastatic involvement of the different cervical LN groups was analyzed and correlated to the pattern of PT invasion of equivalents of PhA and OCS by the chi-square test. The findings show that the pattern of cervical LN involvement depends on the location and extension of the PT and its invasion of equivalents of the PhA and OCS. Jugular LN metastases were found in tumors invading the equivalents of PhA 2-6. Submandibular LN metastases were evident in tumors invading tissues arising from the first PhA and the tongue. Retropharyngeal, spinal accessory and transversa colli LN metastases were found in tumors invading tissues arising from OCS. The frequency of LN metastases in the different LN chains decreased in the cranio-caudal direction. Each neck hemisphere showed separate lymphatic drainage. Analysis of PT extension in relation to PhA and OCS equivalents allows patterns of LN involvement to be predicted.