|
Sentinel Lymph Node Mapping
Proven Effective in Predicting Spread of Breast
Cancer
Surgeons at the University of
Pennsylvania Cancer Center are using a technique
that prevents pain and potential complications
caused by routine lymph node removal in breast
cancer patients. The procedure is called sentinel
lymph node mapping.
In traditional mastectomies or lumpectomies,
surgeons perform an axillary dissection -- removal
of most or all of the lymph nodes -- from the
woman's underarm because the lymph nodes are the
most reliable predictor in determining if the
cancer has spread to other areas of the body. Lymph
nodes, which are small, bean-shaped glands, are
usually found in clusters throughout the body. They
help eliminate bacteria and viruses and are needed
to drain and regulate the flow of lymphatic fluid.
Without lymph nodes, lymphatic fluid builds-up and
many women develop an uncomfortable chronic
condition called lymphedema, which results in arm
swelling and stiffness.
Sentinel lymph node mapping may eliminate this
problem. The procedure involves injecting a
radioactive tracer and a blue dye around the tumor
site. These two substances travel from the tumor
and drain into the sentinel, or main, lymph node.
Together they give the surgeons a visible and
audible marker as to the location of the sentinel
lymph node. "In the past, we've had trouble
identifying the sentinel lymph node and that's why
we previously removed all the nodes," says Brian
Czerniecki, M.D., assistant professor of surgery.
"But this two-armed approach directly points us to
the one or two main nodes that can predict whether
cancer might be found in the rest of the lymph
system."
A hand-held radioactive detector, similar to a
Geiger counter, is scanned around the underarm area
and a beeping sound pinpoints the location of the
radioactive-filled node. After making a small
incision, the surgeon can see the blue-dyed
sentinel node. This node is then removed for
pathological testing.
"If the node tests negative for cancer, we can
accurately predict that the other nodes are also
negative, thus sparing the patient excessive
removal of the nodes," Czerniecki explains.
"However, if the sentinel node tests positive, then
it is necessary to remove the rest of the
nodes."
In a preliminary study, Czerniecki and his
colleagues performed the mapping procedure on 44
patients. In every case, the sentinel node mirrored
the status of the other nodes. "This procedure has
proven between 98-100 percent accurate in that the
sentinel lymph node indicates the state of the
surrounding nodes," says Czerniecki.
Sentinel lymph node mapping was first pioneered
on melanoma patients and, after much success,
surgeons applied the approach to patients with
breast cancer. "By using this procedure, we cut
costs by reducing the amount of pathology tests
needed, but more importantly, we may eliminate
major side effects of breast cancer surgery," he
says.
Czerniecki is currently teaching other surgeons
in the community how to perform this procedure.
"Sentinel lymph node mapping will most likely
become the standard of care for women undergoing
breast cancer surgery, and we're in the process of
teaching surgeons at area hospitals how to perform
the technique."
|