Merkel cell carcinoma of the hand and upper extremity: current trends and outcomes.

Merkel cell carcinomas represent an uncommon yet aggressive skin cancer. We sought to identify changes in incidence and predictors of outcomes and survival of patients with Merkel cell carcinomas of the hand and upper extremity. The Surveillance, Epidemiology and End Results database was used to identify all patients with Merkel cell carcinomas of the skin located specifically in the hand and upper extremity. Overall, 5211 cases were identified in the period from 1986 through 2009. The age-adjusted incidence of Merkel cell carcinoma of the hand and upper extremity increased from 0.02 cases per 100,000 in 1986 to 0.14 cases per 100,000 in 2009. The mean age of these patients was 75 years and positive regional lymph nodes were identified in 33%. Rate of metastasis was 4.1%. Overall survival for the study cohort was 49%. Multivariate analysis identified tumor size >5 cm, positive regional lymph nodes and metastasis at diagnosis as independent predictors of mortality. The incidence of Merkel cell carcinomas has increased substantially over the study period. Overall survival for Merkel cell carcinomas of the body and hand and upper extremity is related to tumor size and extent of disease at time of clinical presentation. Merkel cell carcinomas of the hand and upper extremity tend to be diagnosed at an earlier stage with lower rates of regional and systemic spread, and subsequently have a higher overall survival rate.