Pattern of cervical lymph node metastases in squamous cell carcinoma of the upper oral cavity - How to manage the neck

Objectives: Oral squamous cell carcinoma (OSCC) arising from the upper oral cavity is rare compared to other localizations. While cervical lymph node metastasis (CLNM) can be predicted to some extent, the probability of occult CLNM remains high. The aim of this study is to determine risk factors affecting clinical decision making. Materials and methods: A retrospective analysis of patients surgically treated between 2012 and 2017 for OSCC of the upper oral cavity was performed. Results: A total of 66 patients were included. Of these, 25 patients (37.9%) presented with CLNM after histopathological examination (pN+/cN0: 10/44 (22.7%); pN+/cN+: 15/22 (68.2%)). Lymph vessel infiltration (p = 0.03) and grade of differentiation (p = 0.03) were associated with an increased probability for CLNM. Patients with positive nodal disease at the time of primary surgery showed higher tumor depth of invasion (DOI) than patients without CLNM (mean 10.3 mm +/- 6.9 versus mean 6.1 mm +/- 4.9; p = 0.02). The optimal DOI cutoff value for the prediction of CLNM was 4.5 mm. The OS was significantly higher in patients with a tumor DOI <= 4.5 mm (p = 0.01). Conclusion: Elective neck dissection should be preferably performed for OSCC of the upper oral cavity. For earlystage and clinically node-negative patients, sentinel-lymph node biopsy can be an alternative, especially in patients with a DOI <= 4.5 mm. Since this group had no occult CLNM below this DOI cutoff value, watch and wait might be an alternative for selected patients.