Sentinel lymph node mapping and biopsy is the best way to find out if breast cancer cells have escaped the original
tumor and spread to nearby lymph nodes in the armpit. Sentinel lymph node
mapping and biopsy is usually performed as part of breast cancer surgery.
Although most women with a small breast tumor do not have cancer cells
that have metastasized (spread) to lymph nodes, identifying which women
do have armpit (axillary) lymph node involvement is important because
it helps the medical and radiation oncologists plan additional treatment.
"Sentinel" refers to the first lymph node(s) in the armpit on
the same side of the body as the breast cancer. Since specific lymph nodes
handle drainage from the breast, this node(s) is the most likely place
tumor cells will metastasize if some cells have left the original tumor
by the time of surgery.
The advantage of sentinel lymph node mapping and biopsy is that it is a
less invasive way to obtain information about possible breast cancer spread.
However, a woman who has known cancer spread to her lymph node(s) that
has been confirmed prior to surgery is not a candidate for the mapping
procedure - these women need to undergo axillary dissection, a somewhat
more extensive surgery to the armpit area that removes the lymph nodes
known to contain cancer and additional lymph nodes in the same area to
make as certain as possible that all cancer-containing lymph nodes have
It is important to keep in mind that even if the sentinel lymph node(s)
do not contain any escaped breast cancer cells, this does not guarantee
that no cancer cells have traveled to another part of the body, like the
bones or liver. But studies show that women with breast cancer who undergo
lymph node biopsy that does not reveal any cancer cells in their lymph
nodes have a reduced risk of breast cancer recurrence.
Sentinel Lymph Node Mapping Procedure
Sentinel lymph node mapping begins with a Breast Diagnostic Center radiologist
injecting a very weak radioactive and blue dye solution into the cancerous
area in the breast. The injection must be done at least an hour before
surgery so that the solution has time to drain from the breast to the
sentinel node(s). The isotope dye solution travels via the lymphatic system
and marks the specific lymph nodes most likely to contain cancer cells
if any metastasis has occurred.
After injection of the mapping solution and
needle localization (if indicated), you are transported by hospital mini-bus to the pre-surgery
area in the main hospital. Loved ones who are accompanying the patient
may also travel to the hospital via the mini-bus.
In the OR
In the operating room the surgeon uses a Geiger counter and the dye to
locate the sentinel node(s). A small incision is made so that these nodes
can be removed and sent to the pathology department for immediate frozen
section biopsy to determine if any cancer cells are present. If no cancerous
cells are found, it is a good indicator the cancer has not spread out
of the breast. However, if cancer cells are found in a sentinel lymph
node, the standard of care is for the surgeon to proceed with an axillary
dissection (surgical removal of additional lymph nodes in the armpit to
make as certain as possible that all lymph nodes containing cancer have
Advantages of Sentinel Lymph Node Biopsy
Before the development of the sentinel lymph node mapping procedure, the
only available method to check for presence of cancer in the lymph nodes
was a more invasive axillary dissection. Unfortunately, axillary dissection
includes a greater risk of side effects, including pain, nerve damage
and chronic swelling of the arm. Although sentinel lymph node biopsy does
not completely eliminate the risk of these side effects, the likelihood
of a persistent problem is greatly reduced.
After Sentinel Lymph Node Mapping
For a day or so after sentinel lymph node mapping, the body eliminates
the blue dye through urination. Although the urine typically appears blue
to green, the dye is harmless to the kidneys and urinary system. The patient
can help the body eliminate the dye by drinking plenty of fluids.
If you would like more information about sentinel lymph node mapping, or
any other aspect of breast surgery, ask your breast surgeon or contact the
Breast Navigator RNs at the Breast Diagnostic Center or the Advance Practice Nurses at Torrance Memorial
Cancer Resource Center at 310-517-4665.
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