Background
Merkel cell carcinoma (MCC) is a rare, aggressive malignancy, with high rates of recurrence and metastasis.
Objective
To evaluate predictors of sentinel lymph node (SLN) positivity in Merkel cell carcinoma using the National Cancer Database (NCDB).
Methods
The NCDB, from 2012-2014, was used to identify 3,048 patients with MCC of which 1,174 received a SLN biopsy (SLNB). Predictors of SLN positivity were evaluated using logistic regression, overall survival (OS) was evaluated using a Cox proportional hazards model.
Results
Of patients who underwent SLNB, those with primary lesions on the trunk (OR 1.98, 95%CI 1.23-3.17, p=0.004), tumor infiltrating lymphocytes (OR 1.58, 95%CI 1.01-2.46, p=0.04), or lymphovascular invasion (OR 3.45, 95%CI 2.51-4.76, p<0.001) were more likely to have positive SLN on multivariate analysis. OS was negatively affected by age ≥75 (HR 2.55, 95%CI 1.36-4.77, p=0.003), male gender (HR 1.78, 95%CI 1.09-2.91, p=0.022), immunosuppression (3.51, 95%CI 1.72-7.13, p=0.001), and SLN positivity (3.15, 95%CI 1.98-5.04, p<0.001).
Limitations
Lack of disease specific survival, potential selection bias from a retrospective dataset.
Conclusions
Truncal MCC, tumor infiltrating lymphocytes and presence of lymphovascular invasion were independent predictors of positive SLN. OS was negatively affected by advancing age, male gender, immunosuppression, and SLN positivity.
