Tumor Location Is an Independent Prognostic Factor in Head and Neck Merkel Cell Carcinoma

Objective. Explore the relationship between tumor location and prognosis among patients with Merkel cell carcinoma (MCC) of the head and neck. Study Design. Retrospective analysis of large population database. Setting. Surveillance Epidemiology and End Results (SEER) database/multiple settings. Subjects and Methods. Using the SEER database, the authors identified patients with MCC of the head and neck. They compared clinicopathologic characteristics and disease-specific survival (DSS) between patients with head and neck MCC at different anatomic subsites. DSS was estimated by the Kaplan-Meier method, and a multivariable regression model was constructed so that independent predictors of DSS could be determined. Results. Of the 2104 patients identified, 61.0% were men. The mean age at diagnosis was 77.5 years. Tumors were most commonly located on the face (61.1%). Scalp tumors were significantly larger (10.4% >5 cm, P = .0001) and more likely to present with distant metastasis (8.7%, P = .07) than other head and neck tumors. Lip tumors had the highest rate of invasion into bone, cartilage, and muscle (13.7%, P = .012), and ear tumors had the highest rate of nodal metastasis (63.2%, P = .011). Patients with scalp/neck and lip primary sites had significantly worse survival on univariable analysis (P = .0054 and P = .0007, respectively); however, the lip was the only site associated with worse survival on multivariable analysis (hazard ratio = 1.8, P = .005). Conclusions. This study is the first to report lip location as an independent prognostic factor in head and neck MCC. More aggressive treatment of patients with MCC of the lip may be warranted to improve outcomes.