In the past, nearly any woman undergoing any type of surgery for breast cancer, underwent a procedure known as axillary lymph node dissection.

Axillary lymph node dissection involves the removal of between 10 and 15 lymph nodes from the underarm area in order to see if cancer has spread beyond the initial tumor site. A pathologist checks each node for signs of metastasis. The procedure typically requires an overnight hospital stay and the placement of a flexible plastic tube beneath the skin to allow lymph fluid from the affected area to drain. After a couple of weeks, when the area has had time to heal, the tube is removed. Unfortunately, as many as 10% of the women who undergo this procedure experience lymphedema or muscle damage, and almost all will experience some level of permanent numbness.

Sentinel node biopsy, an alternative method of determining if cancer has spread, is gaining ground and recently received a boost from the endorsement of an international group of breast cancer specialists.

This “new” method is actually over 10 years old, but it is rapidly receiving wider exposure and acceptance.

In every person, there is a specific path through the lymph system that any foreign matter will traverse. This pattern is unique to each person. For this reason, if a surgeon can locate the first node on the lymphatic path traveling away from a breast tumor site, and remove it for analysis, further node removal might be unnecessary. The idea is that if this first, or “sentinel” node shows no sign of cancer, then the cancer has not spread.

Because the sentinel node can be in a different location in each individual, a weak radioactive dye, or a blue dye (or both) is injected near the tumor site. The path of the injected material is traced, and 1-3 potential sentinel lymph nodes are removed.

The advantages of this procedure include no overnight stay in the hospital, no drainage tube, faster recuperation, and less likelihood of lymphedema.

However, until clinical studies prove conclusively that sentinel node biopsy is as effective as axillary node dissection, many surgeons will continue to use the latter procedure. Knowing for certain whether or not breast cancer has spread is one of the most important factors in determining a course of treatment.

Initial studies have indicated that sentinel node biopsy does, in fact, have a rate of success similar to axillary node dissection. Further studies are underway at a number of sites across the US.