Challenges documenting racial disparities in Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer that predominantly impacts White patients. Overall incidence and the proportion of minority patients with MCC are both rising. In the more common skin cancer, melanoma, racial disparities are well-documented in stage at presentation and patient survival. Whether racial and ethnic disparities exist in MCC remains unclear. The study of MCC disparities is hampered by limitations in data registries, including SEER and NCDB, and an evolving natural history due to the advent of immunotherapy. Published MCC immunotherapy clinical trials consistently reported the racial diversity among enrolled subjects but failed to include patients' ethnicities. Efforts to improve data capture in cancer registries and create multi-institutional clinical databases will allow for more effective study of racial and ethnic disparities in rare cancers like MCC. Such studies are needed to advance policies promoting equity in care.