The epidemiology of Merkel cell carcinoma in the United States

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer with poor outcomes. Many questions remain regarding its epidemiology.

To characterize the epidemiology of MCC.

We conducted a retrospective, population-based epidemiologic study of all cases of MCC from the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2021. Incidence and mortality rates were calculated using SEER∗Stat software and SEER 12 (1992-2021) and joinpoint analysis was used to assess changing trends. Cause-specific Cox regression was used for competing risk analysis of survival.

In total, 11,574 patients were identified. Median age at diagnosis was 77, and median survival was 45 months. Incidence did not significantly change since 2013, averaging 0.68 per 100,000 person-years over that time. Mortality stabilized and slightly decreased after 2010, with an average rate of 0.16 since that time. Increased mortality was associated with older age, male sex, increased stage, and location on the scalp and neck. Diagnosis between 2016 and 2021 was associated with improved survival.

Incomplete data and inconsistent variable coding in SEER data impact the interpretation of these findings.

The reported incidence and mortality of MCC have stabilized in recent years. Recent diagnosis was associated with improved survival.