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

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.

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.

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.

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.