Nonmelanoma Cutaneous Head and Neck Cancer and Merkel Cell Carcinoma: Current Concepts, Advances, and Controversies

Abstract

Nonmelanoma skin cancer (NMSC) is the most common cancer worldwide and the most frequently observed malignancy in whites. Approximately 75% to 80% are basal cell carcinomas and 20% to 25% are squamous cell carcinomas. Incidence is increasing, partly reflecting an ageing population, and NMSC is more commonly seen in men. The predominant causative agent is ultraviolet solar radiation exposure, with the majority of cases occurring on the head and neck. Surgical excision is typically the treatment of choice, providing histopathologic information, high cure rates, and acceptable cosmetic and functional outcomes. Radiation therapy is reserved for cases where surgery is not the preferred choice or for high-risk cases where adjuvant therapy is recommended. Although overall mortality rates are low, patients with complex cases such as those with immunosuppression should be considered for management within multidisciplinary tumor boards. In contrast, Merkel cell carcinoma is a rare and aggressive malignancy, frequently arising on the head and neck in older whites, with a poorer prognosis. This article focuses on the current evidence guiding practice, recent advances, and areas of controversy in NMSC and Merkel cell carcinoma of the head and neck.