Clinicopathologic Factors Predictive of Occult Lymph Node Involvement in Cutaneous Head and Neck Melanoma

Objectives Evaluate clinicopathologic factors contributing to regional lymph node (LN) metastases in cutaneous head and neck melanoma (HNM). Study Design Retrospective review of a national cancer database. Setting National Cancer Database (2004-2012). Methods National Cancer Database (NCDB) cases diagnosed between 2004 and 2012 were reviewed. Inclusion criteria were head and neck cutaneous site codes, melanoma histology codes, and clinically node-negative status. Independent, clinicopathologic factors associated with pathologic positive LN status were identified by multivariable logistic regression. Subset analysis was performed on thin melanoma cases of 0.75 to 1 mm tumor depth to determine factors predictive of LN involvement and survival. Results Of 66,495 cases meeting inclusion criteria, 18,882 had nodes examined pathologically with 9.7% presenting with occult positive LN involvement. Mean (SD) age was 62.9 (16.13) years, and primary sites were scalp and neck (42.2%), face (40.2%), and external ear, lip, or eyelid (7.6%). Multivariable analysis found younger age; primary site of cutaneous scalp, neck, or face; increasing thickness; mitoses; ulceration; and vertical growth phase presence were independently associated with LN positivity ( P < .001). Only 2% of 0.75- to 1.0-mm Breslow thickness cases had regional LN involvement, and age >70 was negatively associated with LN involvement ( P = .002) in this subset. Conclusion This is the largest study examining factors predictive of occult LN involvement in patients with clinical node-negative cutaneous HNM who may benefit from sentinel LN biopsy. Primary sites of external ear, lip, or eyelid are less likely to present with occult nodal involvement, and older patients with T1a melanoma ≥0.76 mm are unlikely to present with regional node metastasis and may not require sentinel node guided management.