Improved survival at the population level for patients with advanced Merkel cell carcinoma following availability of immunotherapy.

Abstract

Merkel cell carcinoma (MCC) is an aggressive skin cancer with poor survival rates. Immune checkpoint inhibitors (ICIs) were Food and Drug Administration-approved for advanced MCC in 2017, but their real-world survival impact remains unclear. Evaluate whether ICI introduction in the United States corresponded with improved survival. This cohort study analyzed Surveillance, Epidemiology, and End Results data for MCC patients diagnosed from 2010 to 2021, grouped by 3-year periods, to calculate 2-year overall and relative survival. For 453 patients with metastatic MCC, 2-year relative survival improved from 23% (2010-2012) to 37% (2013-2015), 42% (2016-2018), and 54% (2019-2021) (P < .001). Median overall survival also increased from 9 to 16 months among these patients. In 4786 MCC patients overall, 2-year relative survival rose from 73% (2010-2012) to 81% (2019-2021) (P = .004), while overall survival improved from 67% to 72% (P = .012). Surveillance, Epidemiology, and End Results lacks case-level data to link ICI treatment directly to survival, although ICIs represent the major recent treatment advance for MCC. The introduction of ICIs aligns with a >2-fold increase in survival for advanced MCC patients at the population level, translating to ∼220 fewer deaths per year in the United States.