Merkel Cell Carcinoma: A Population Analysis on Survival.

PURPOSE: Merkel cell carcinoma (MCC) is an aggressive cutaneous malignancy. However, factors associated with disease presentation and outcomes remain uncertain, especially in light of recent changes in workup, such as sentinel lymph node biopsy. Therefore, this study used the SEER database to examine factors that could affect stage at presentation and treatment.

METHODS: We identified 4,543 patients and evaluated associations between sex, race, age, primary disease site, disease presentation, and treatment. We also used univariate and multivariate analyses to examine the effect of these factors on disease-specific survival (DSS) and overall survival (OS). We specifically conducted subgroup analyses on a more modern cohort of patients with MCC treated between 2006 and 2012.

RESULTS: Male sex, older age, larger tumor size, and primary tumors of the scalp, neck, or trunk were associated with a higher burden of nodal disease. Multivariate predictors of worse DSS/OS in both the recent and overall cohort included age older than 75 years, number of lymph nodes involved, tumors greater than 5 cm, metastatic disease, or lack of radiation therapy. The number of involved nodes was the best predictor of DSS/OS. Associations with radiation therapy were most pronounced in patients with nodal disease and those not undergoing surgery.

CONCLUSIONS: Sex, age, tumor size, and primary site of disease correlated with burden of nodal disease in MCC. Associations between disease presentation and treatment strategies such as radiation and DSS and OS have remained relatively constant in the modern era from 2006 to 2012 compared with findings from prior studies.