The distribution of lymph node metastases in supraglottic squamous cell carcinoma: therapeutic implications.

Background: The treatment of the neck in cancer of the upper aerodigestive tract is still a matter of controversy, even though nowadays there is a trend in the literature toward elective surgery in the N0 neck when the probability of occult lymph node metastasis is greater than 20%. In the elective setup, every effort is made for preservation of uninvolved nonlymphatic structures in positive neck. The aim of this study is to analyze in a large cohort of patients treated for supraglottic carcinoma the prevalence of lymph node metastases and their distribution through various neck levels to redefine our policy of neck treatment.

Methods: A retrospective review of 402 consecutive patients, who underwent surgery in the Department of Otolaryngology of the University of Brescia (Italy) for supraglottic squamous cell carcinoma in a 14-year period, has been performed. The prevalence of neck metastases was assessed by pT category and site (marginal vs vestibular) of the primary tumor. The side(s) of neck disease was related to the side of the primary tumor, whether lateral or central. The distribution of involved lymph nodes through the neck levels was determined.

Results: Overall lymph node metastases accounted for 40%; their prevalence rate increased with pT category from 10% to 57% (p =.0001). Occult metastases were found in 26% of N0 patients from 0% in pT1 to 40% in pT4 (p =.02). There was no difference in metastases rate between marginal vs vestibular, and central vs lateral neoplasms, whereas bilateral metastases were more frequent in central tumors (20% vs 5%; p <.0001). Level IV was involved only in association with level II and/or level III. Levels I and V were rarely involved when overt metastases were present and never by occult metastases.

Conclusions: Elective lateral neck dissection (levels II-IV) is recommended in T2-T4 N0 supraglottic cancers; clearance of both sides of the neck is indicated whenever the lesion is not strictly lateral. We still perform a selective neck dissection including levels II-V whenever there is clinical, radiologic, or intraoperative evidence of metastases at any level.