Last updated: 02/17/2009

Sentinel lymph node biopsy (SLNB) is a minimally invasive procedure in which a lymph node near the site of a cancerous tumor is first identified as a sentinel node and then removed for microscopic analysis. SLNB was developed by researchers in several...

different cancer centers following the discovery that the human lymphatic system can be mapped with radioactive dyes, and that the lymph node(s) closest to a tumor serve to filter and trap cancer cells. These nodes are known as sentinel nodes because they act like sentries to warn doctors that a patient's cancer is spreading.

The first descriptions of sentinel nodes come from studies of penile and testicular cancers done in the 1970s. A technique that uses blue dye to map the lymphatic system was developed in the 1980s and applied to the treatment of melanoma in 1989. The extension of sentinel lymph node biopsy to the treatment of breast cancer began at the John Wayne Cancer Institute in Santa Monica, California, in 1991. As of 2003, SLNB is used in the diagnosis and treatment of many other cancers, including cancers of the head and neck, anus, bladder, lung, and male breast.