Merkel cell carcinoma overall survival based on extent of nodal disease

Five-year OS of 2465 Merkel cell carcinoma patients with regional lymph node metastases in the NCDB, stratified by tumor burden and primary tumor status: clinically and radiologically occult nodal metastasis (N1a) detected by SLNB or otherwise; clinically or radiologically detected and pathologically confirmed nodal metastasis (N1b) with or without the presence of a primary tumor; and in-transit disease (N2). The latter category represents 3-year OS because of the small sample size of 60 patients.