Background: External ear melanoma (EEM) is a rare condition with controversies in the literature. We analyzed patients with EEM in the United States compared to other head and neck melanomas (OHNMs).
Methods: The National Cancer Database (NCDB) was used to select patients with head and neck melanoma from January 1, 2004 to December 31, 2015. Mann-Whitney and χ tests were used to estimate statistical significance, and multivariate logistic regression to identify independent associations adjusted for confounders.
Results: A total of 137,233 patients met the study criteria. Among them, 16,991 (12.4%) had EEM and 120,242 (87.6%) had OHNM. For patients with EEM, the mean (standard deviation) age was 66.26 (15.798) years. Most of the patients with EEM were men (85.5%), insured by Medicare (52.4%), and treated in Academic/Research Programs (47.7%) or Comprehensive Community Cancer Programs (32.3%). Most of the EEM tumors had invasive behavior (68.0%) were Stages 0 (30.3%) or I (40.3%), and were without ulceration (76.9%). Mean time to receive any treatment was 14.1 days for EEM compared with 14.6 days for OHNM (P < 0.001). We noticed a greater proportion of EEM in men (14.8%; adjusted odds ratio [aOR] 2.72 [2.605-2.852]; P < 0.001) compared to women (6.22%; reference). EEM was an independent factor for tumor Stage I (14.47%; aOR 1.61 [1.101-1.224], P < 0.001) and invasive behavior (13.86%; aOR 1.268 [1.15-1.389]; P < 0.001) compared to OHNM.
Conclusion: EEM was associated with higher odds of invasive behavior compared to OHNM. Furthermore, men were found to have a higher likelihood to develop EEM compared to women.