NCIt definition : The first lymph node that is affected by cancer spread from the primary site. Sentinel
lymph node biopsy is part of the staging work-up to determine early metastasis to
regional lymph nodes in patients with breast carcinoma or melanoma.;
Alternative definition : NCI-GLOSS: The first lymph node to which cancer is likely to spread from the primary
tumor. Cancer cells may appear first in the sentinel node before spreading to other
lymph nodes.;