Merkel Cell Carcinoma of the External Ear: Population-Based Analysis and Survival Outcomes

SIMPLE SUMMARY: Merkel Cell Carcinoma (MCC) is a neuroendocrine skin tumor with malignant characteristics. Multiple regions can be affected, and tumoral incidence and outcomes vary depending on the primary site. A multidisciplinary team management is of paramount importance to offer the best treatment options to patients. Due to the low incidence of MCC, fine analysis of specific regions is limited, particularly the external ear. We performed a population-based analysis of demographic and survival outcomes of external ear MCC. The aim of this study is to offer updated data on tumor behavior and survival outcomes of this specific region. The male gender, an age over 80 years old and a tumor size above 5 cm were risk factors for low overall survival. Gross (<1 cm) and wide (>1 cm) margins of surgical excision offer the best overall survival. ABSTRACT: (1) Background: Due to its highly aggressive behavior, the ability to identify and manage Merkel Cell Carcinoma (MCC) with a full understanding of its characteristics is essential. Because the external ear is an exposed area, resection can have dramatic consequences on patient’s self-image, which is why it is fundamental to detect MCC, typically found on UV-exposed regions such as the ears, at an early stage. (2) Methods: The Surveillance, Epidemiology, and End Results (SEER) database was searched for all external ear MCC between 2000 and 2019. A descriptive analysis based on frequencies was made to describe the demography of pathophysiologic features linked to MCC. Overall survival (OS) was studied and compared between variables with a log rank test. A multivariable Cox regression analysis was then computed to identify independent prognostic factors. (3) Results: A total of 210 patients (160 men) were identified with a median age of 80 years. The median OS was 47 months. Factors associated with lower OS included an age of over 80 years, the male gender, a tumor size of >5 cm, and metastatic disease. Gross (<1 cm) and wide (>1 cm) surgery excision margins were the surgery types with the best OS. (4) Conclusions: MCC of the external ear is diagnosed mostly in old men. Among the 182 patients who received a surgical procedure, gross and wide excision without radiotherapy were associated with the best OS.