Sentinel Node Biopsy
A biopsy of axillary lymph nodes is an important diagnostic test in staging the spread of breast cancer. If a cancerous breast lump is detected, it becomes essential to determine if the cancer has spread to the surrounding lymph nodes. If breast cancer is going to spread, it usually spreads first to the lymph glands under the armpit. The first node that develops cancer is known as the sentinel node.

To perform sentinel node biopsy, physicians inject the area of the breast cancer with a blue or radioactive dye that slowly leaks into the lymph glands of the armpit. After making an incision in the armpit, the physician can identify the sentinel node by the color or radiation output. If the sentinel node testing does not reveal cancer, then the rest of the lymph nodes are usually cancer free.

Sentinel node biopsy can save the patient from undergoing lymph node resection when it is not necessary. About 10 to 20% of women who undergo aggressive lymph node resection under the arm suffer from chronic arm swelling and pain.