Merkel Cell Carcinoma: Current United States Incidence and Projected Increases based on Changing Demographics

Abstract

Background: Merkel cell carcinoma (MCC) incidence rates are rising and strongly age-associated, relevant for an aging population.

Objective: Determine MCC incidence in the United States and project incident cases through the year 2025.

Methods: Registry data were obtained from the SEER-18 database, containing 6,600 MCC cases. Age and sex-adjusted projections were generated utilizing US census data.

Results: Between 2000-2013, there was a 95% increase in the number of reported MCC cases, compared to 57% for melanoma and 15% for all ‘solid’ cancers. In 2013, the MCC incidence rate was 0.7 per 100,000 person-years in the US, corresponding to 2,488 cases. MCC incidence increased exponentially with age, from 0.1 to 1.0 to 9.8 (per 100,000 person-years) between age groups 40-44, 60-64, 85+ years, respectively. Due to aging of the “baby-boom” generation, US MCC incidence is predicted to climb to 2,835 cases in 2020 and 3,284 cases in 2025.

Limitations: Projections assume the age-adjusted incidence rate stabilizes and thus may be underestimates.

Conclusions: An aging population is driving brisk increases in the number of new MCC cases in the US. This growing impact combined with a rapidly evolving therapeutic landscape warrants expanded awareness of MCC diagnosis and management.