What is Sentinel Lymph Node Biopsy?
After a lesion is diagnosed as cancerous, it is important to know if the cancer has spread to other areas of the body (metastasized). One of the methods used to determine metastasis is sentinel lymph node biopsy. The rationale for sentinel lymph node biopsy is based on the premise that metastasis is not a random event. Migration of cancer cells to distant parts of the body often occurs via blood vessels (veins/arteries) and the lymphatic system.
The lymphatic system is part of the immune system, the body's defense against infection. It includes an extensive network of vessels and some grape-like clusters of lymph nodes (regional collection centers). If a cancer cell leaves the site from which it originated (the primary tumor) via the lymphatic system, it floats through the vessels until it reaches the next group of lymph nodes.
Learn more about the lymphatic system here.
For any region of the body, it is possible to predict which lymph node(s) are most likely to have been reached by a migrating cancer cell. These are known as sentinel lymph nodes (SLN). The sentinel node is the first node to receive drainage from the tumor area, metastasizing cancer cells leaving the tumor are most likely to collect in the SLN. If no cancer cells are found in the SLN it is much less likely that cancer cells have invaded the lymphatic system and moved to other parts of the body.
Click on the image below to view a documentary on sentinel lymph node biopsy. Be sure to return to read the rest of our SLN information.
The following pages describe the process of SLN biopsy in detail: