Lymph Node Involvement

Lymph nodes are small bean-shaped organs that are found throughout the body.  Their job is to filter the fluid in the lymphatic channels before it flows back in the blood system, draining waste products and trapping abnormal cells – including cancer cells.  They are essential parts of the body's immune system, but can become incubators for cancer cells.  When cancer cells reach lymph nodes, they sometimes begin growing there.  Determining whether cancer has spread to the nearby lymph nodes is very important.  If it has, the risk is much greater that it will or has spread to another part of the body.  Knowing lymph node status is critical to determining proper treatment for every breast cancer.

The standard practice for many years was to remove a large number of axillary lymph nodes (the ones closest to the breast, located under the arm) and to examine them for signs of microscopic cancer growth.  This surgery is known as axillary lymph node dissection.  It is still indicated in many instances, but, in recent years, doctors have discovered that removing all the axillary lymph nodes is often not necessary, and can lead to great morbidity consisting of arm lymphedema, or swelling.  Today surgeons perform a sentinel node biopsy, a procedure in which a blue dye and/or radioactive tracer is used to map the first draining nodes of the breast tissue, which signify the nodes that will have cancer if the disease has spread.  Surgeons remove only those nodes closest to the tumor (usually 1-5 nodes).  It is based on the theory that, if the cancer has not spread to those nodes, it is very unlikely to have spread to nodes farther from the cancer.  However, not everyone is a candidate for this procedure.

The sentinel node biopsy significantly reduces the amount of surgery necessary to obtain an accurate diagnosis – and also reduces both the short and long term effects of the surgery.  Women who undergo sentinel node biopsies generally experience less pain, have shorter recovery times, and do not develop lymphedema (a chronic swelling in the arm) as often as those who have axillary lymph node dissections.