Sentinel Lymph Node Mapping

Once a person has been diagnosed with breast cancer, it is important to determine if the cancer has spread to the axillary (armpit) lymph nodes.

In the past, surgeons have routinely removed several (ten to twenty) lymph nodes to make that determination. This procedure, termed axillary dissection, does have some side effects. These include a possible frozen shoulder, numbness in the armpit and upper arm, and lymphedema (swelling of the arm).

A new technique has been developed to pinpoint the lymph nodes most likely to be involved with cancer cells. This technique is called Sentinel Lymph Node Mapping. It is defined as the first lymph node(s) that a cancerous tumor would drain to.

Sentinel Lymph Node Mapping always involves injection of a blue dye around the tumor just before surgery is performed (5 minutes). Often, a radioactive material (technetium) will also be injected in the breast by a radiologist a few hours prior to surgery.

There are minimal side effects from the injection of the radioactive material and blue dye. The technetium is a commonly used material in nuclear medicine tests and the dose used for Sentinel Lymph Node Mapping is less than that used in many radiology procedures. The blue dye can occasionally be seen on the breast skin and last for a few months. It does get absorbed into the system and may shed a "blue cast" to the skin for the first few hours. Also, it is excreted through the urine and the following day, your urine may turn blue.

Both the blue dye and the radioactive material travel to the lymph nodes. These specific nodes, "blue" to the naked eye of the surgeon and or "hot" from the radioactive material when using a hand-held Geiger counter, will be sampled.

If these nodes show cancer cells, then a routine axillary dissection will be performed. A drain will be placed for several days and the patient usually stays overnight in the hospital. If the nodes are negative, then usually no other nodes are removed and a patient may go home after surgery.

Occasionally, neither of these techniques points to any lymph nodes in the axilla and a routine axillary dissection will be performed. This may be seen if the breast tumor surgery was already performed and was extensive.

In approximately 10% of the cases, the immediate interpretation of the lymph nodes (frozen section) is negative, but a more detailed analysis reveals tumor cells. A delayed routine axillary dissection will then to be performed.

Dr. Sickle-Santanello is experienced in the field of Sentinel Lymph Node Mapping.