Incidence of Cervical Lymph Node Metastasis and its Association with Outcomes in Patients with Sinonasal Mucosal Melanoma

Background: Mucosal melanomas in the head and neck region are most frequently located in the nasal cavity and paranasal sinuses. The patterns of regional metastasis and the role of neck dissection in sinonasal mucosal melanoma (SNMM) are not established.

Methods: This retrospective study investigated 96 patients with SNMM treated between 1985 and 2016 in MD Anderson Cancer Center. Clinical and pathologic nodal status was evaluated and characterized for all patients. Multivariate analysis assessed associations of regional spread with survival outcomes.

Results: The incidence rate of neck metastases was 13%. The rate observed in tumors originating from the nasal cavity was 16.18%, and from the paranasal sinuses was 8.7% (p = 0.05). The rate of occult nodal metastases was 3%. The rate of involved neck levels was 5%, 5%, 2% and 1% for levels I, II, III and Va, respectively. None of the patients had contralateral nodal metastasis. Overall 5-year survival (OS) rates were 55% in patients that did not undergo neck dissection, and 58% among those undergoing neck dissection (p = 0.55). Univariate analysis showed nodal classification and neck dissection status were not associated with 5-years disease free survival (DFS) or regional recurrence free survival. Multivariate analysis revealed that the primary site, metastasis classification, margin status and adjuvant treatment were independent predictors of 5-years OS and DFS.

Conclusion: The incidence of occult neck metastases among patients with SNMM is 3%. The highest incidence of nodal metastases was with tumors arising from the nasal cavity. Statistical analysis showed no survival advantage for patients who underwent neck dissection compared with those who did not.