Patterns of lymph node metastasis in 441 patients with sinonasal squamous cell carcinoma.

Background: Due to the rarity of sinonasal squamous cell carcinoma (SNSCC), the distribution patterns of lymph node metastasis (LNM), the relationship between LNM and prognosis, and the optimal treatment of LNM lack sufficient evidence-based support.

Objectives: To investigate the patterns of LNM in SNSCC and evaluate the impact of LNM on prognosis.

Design: This was a retrospective cohort study.

Methods: The medical records of 441 patients with SNSCC between 2009 and 2022 in one institution were retrospectively reviewed. We assessed the incidence, the distribution of LNM, and the relationship between LNM and long-term survival.

Results: Seventy-three out of 441 patients (16.6%) presented LNM initially. Among the 73 patients, 34 patients (46.6%) had LNM in the region of ipsilateral level II; 22 patients (30.1%) had positive retropharyngeal lymph nodes; 20 patients (27.4%) had LNM in the region of ipsilateral level Ib; and nine patients (12.3%) had evidence of parotid LNM. Poor differentiation (p = 0.001), nasal cavity (p = 0.018), skin involvement (p = 0.036), and nasopharynx involvement (p = 0.009) were the risk factors for LNM. In the univariate and multivariate analyses, the overall survival (p = 0.25), progression-free survival (p = 0.22), regional failure-free survival (p = 0.20), and distant metastasis-free survival (p = 0.14) rates were not significantly decreased by the LNM. After the propensity score matching, LNM was still not correlated with poor long-term survival.

Conclusions: The incidence of retropharyngeal and parotid LNM was higher than in previous studies. At initial diagnosis, the risk factors for LNM were identified, and LNM was not associated with poor survival outcomes.