Primary head and neck mucosal melanoma: Predictors of survival and a case series on sentinel node biopsy

Introduction: Head and neck mucosal melanoma (HNMM) is a rare tumor with a poor outcome. The objective of this study was to assess outcome and prognostic factors for a cohort of patients treated in a head and neck cancer center. In addition, a case series on sentinel lymph node biopsy (SLNB) was included to evaluate it as a method for staging the node-negative neck.

Methods: A retrospective study design was chosen, and 50 patients who were treated from 1973 to 2015 in our institution for primary HNMM were included. The Kaplan-Meier method was used to estimate survival rates. Uni- and multivariate analyses were used to study the influence of possible risk factors on the patients' outcome. These risk factors included patient demographics, tumor characteristics, and treatment modalities.

Results: All patients were treated surgically and 50% received adjuvant treatment. The median disease specific survival (DSS) was 38 months, with a 5-year survival rate of 44%. Positive surgical margin (p = 0.004) and distant failure (p = 0.005) were associated with a worse DSS. The median disease-free survival (DFS) was 27 months, with a 5-year disease-free rate of 12%. Only tumor depth >5 mm (p = 0.002) was associated with a worse DFS. Five clinically node-negative patients received SLNB and only the two SLN-positive individuals suffered from distant failure. Radiotherapy, chemotherapy, and AJCC/UICC stage had no influence on any outcome measure.

Conclusions: Positive surgical margin and distant failure are the only independent prognostic factors for DSS. Tumor depth can predict distant failure. SLNB may be a valuable staging tool for the node-negative neck.