Demographics, tumor characteristics, and survival of MCC patients with and without metastatic disease to bone, brain, liver, and lung at time of diagnosis

This study used SEER registry data from 2010–2022 to identify patients diagnosed with Merkel cell carcinoma and stratify them based on whether distant metastases to the liver, bone, lung, or brain were present at the time of diagnosis. Demographic information, tumor characteristics, and disease-specific survival outcomes were analyzed. The data demonstrate that patients with metastatic disease at presentation have significantly worse survival compared to those without metastases, and that prognosis differs by metastatic site. Liver metastases were associated with the poorest overall outcomes, followed by brain and bone, while lung metastases showed intermediate but still reduced survival. There was evidence of improved two-year disease-specific survival in the more recent treatment era (2017–2022), which may correlate with increased use of immunotherapy, though overall mortality in metastatic MCC remains high.