Lymph node ratio as an independent prognostic factor in cN0 floor of mouth squamous cell carcinoma: A single-institution retrospective cohort analysis.

Background: To analyze the influence of lymph node ratio (LNR) in survival of clinically node-negative (cN0) patients with floor of mouth squamous cell carcinoma (FMSCC).

Methods: Clinicopathologic data from 48 patients with cN0 FMSCC who underwent curative surgery and selective neck dissection from 2015 to 2020 was retrospectively assessed. The impact of LNR and other variables on overall survival (OS) and disease-free survival (DFS) was analyzed in univariate and multivariate analyses.

Results: Occult nodal metastases were identified in 11 patients (22.9 %). The mean lymph node yield was 13.94 ± 7.11 nodes. ROC curve analysis identified an optimal LNR threshold of 0.034, with an area under the curve of 0.691 (p = 0.03). In the multivariate analysis, LNR was an independent prognostic factor for both OS (HR 9.018, 95 % CI 3.214-25.306, p < 0.001) and DFS (OR 12.889, 95 % CI 2.426-68.473, p = 0.002). Patients with LNR >0.034 demonstrated significantly inferior 5-year OS rates (26.7 % versus 89.1 %).

Conclusions: The LNR is an independent prognostic factor in cN0 FMSCC patients. An LNR threshold of 0.034 effectively stratifies risk and may guide adjuvant therapy decisions.