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.
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