Sentinel lymph node biopsy
Sentinel lymph node biopsy is used to help detect the spread of breast cancer to the underarm lymph nodes. Breast cancer often spreads to the 10-25 underarm lymph nodes. An axillary lymph node dissection, or surgical removal of the lymph nodes, traditionally is used to determine if the cancer has spread by removing most of the lymph nodes and examining them. Potential side effects of axillary lymph node dissection include numbness of the upper arm, swelling and pain.
The sentinel lymph node biopsy allows surgeons to identify a few sentinel lymph nodes to which the cancer would spread first. By doing this, symptoms of swelling and pain would be decreased.
In a sentinel lymph node biopsy procedure, the patient is injected with a small amount of radioactive tracer and blue dye around the breast. The tracer and the dye travel to the sentinel nodes, taking the same route as cancer cells would. The sentinel node is identified by the blue color and with the use of a sensitive Geiger counter. Once identified, the sentinel node is removed and analyzed for the presence of cancerous cells.
Studies have shown that if the sentinel lymph node is negative for cancer, it is unlikely that there are other lymph nodes that contain cancer.