Breast
Cancer Staging By Sentinel Node Biopsy Backed
Less Invasive
Procedure Determines Whether Cancer Has Spread
For decades, women
with breast cancer were advised to have aggressive surgical
treatment intended to prevent the disease from spreading further.
Physicians
are now rethinking that strategy, thanks to the development
in the past decade of a far less invasive procedure to determine
if or to what degree the cancer may have spread.
The
newer approach looks for signs of cancer in the "sentinel" lymph
node, which is the first to collect fluid and cells draining
from breast tumors.
A
new study suggests sentinel node biopsy may be a viable alternative
for many women.
"Sentinel
node biopsy is a safe and accurate method of screening the axillary
nodes (group of lymph nodes under the arm) for metastasis (cancer
spread) in women with a small breast cancer," the authors write
in the New England Journal of Medicine (NEJM).
According
to the National Cancer Institute (NCI), physicians
use information from the sentinel node to determine if cancer
cells have have spread to the other lymph nodes.
In
sentinel node biopsy, only one of a few lymph nodes are removed
for lab analysis when a woman has a lumpectomy or a mastectomy.
Early studies have suggested that if an analysis finds no cancer
cells in the sentinel node, the woman is unlikely to have tumor
cells in the remaining axillary nodes.
The
NCI states that standard treatment usually
involves removing a breast tumor by either lumpectomy or mastectomy,
and removing most of the axillary nodes (axillary node dissection).
Several
complications can arise from removing axillary nodes, and some
reports show that more than 80 percent of women who undergo
a complete axillary node dissection have at least one complication
after surgery.
These
complications vary in severity, but may include lymphedema (a
swelling in the arm caused by excess fluid buildup), numbness,
a burning sensation, infection, and limited movement of the
shoulder.
Less
Surgery Linked to Fewer Problems
Breast
cancer is the most common cancer among women, excluding non-melanoma
skin cancer. Currently, approximately 3 million women in the
US are living with the disease, including 2 million who have
already been diagnosed, and another 1 million who do not yet
know they have the disease.
The
American Cancer Society estimates for 2003
include 211,300 new cases of invasive breast cancer being diagnosed
in the US. In addition, ductal carcinoma in situ will be responsible
for 55,700 new cases this year.
In
the current study, researchers followed 516 women with small
breast tumors (less than about an inch in diameter). Of these
women, half had the sentinel node biopsy and half had axillary
node dissection.
After
five years, the two groups had roughly the same probability
of their cancer spreading to a different organ, the researchers
say.
"There
was less pain and better arm mobility in the patients who underwent
sentinel node biopsy only than those who also under went axillary
dissection," the authors write.
Previous
research has shown sentinel node samples are incorrectly negative
between 5 percent and 15 percent of the time, a relatively high
figure. The Italian study had a false negative rate of about
8 percent, the researchers said.
Still,
Dr. Umberto Veronesi, director of the European Institute of
Oncology in Milan and leader of the research, believes that
in the long run the procedure may save more lives than removing
all the lymph nodes.
"We
believe that leaving normal lymphatic tissue [in the armpit]
will help protect women and help patients do better," Dr. Veronesi
says.
Defining
Studies Currently Underway
Dr.
David Krag, a University of Vermont cancer surgeon who helped
develop the sentinel node biopsy, says two major questions about
the surgery remain: Do the savings in side effects and discomfort
over conventional surgery come at the price of an increased
risk of death? And does it offer less than desired control
of cancer in the breast itself?
Two
studies now under way should answer those questions definitively,
says Dr. Krag, co-author of an editorial accompanying the NEJM
journal article.
Each
is a comparison of sentinel node surgery with axillary tissue
removal. Dr. Krag is leading one of the trials, which has enrolled
more than 5,000 women and includes more than 200 surgeons.
"Until
those studies are completed, we really won't have that information,"
says Dr. Krag. He expects to see results within a few years.
One
in three cases of breast cancer spreads to the lymph nodes,
Dr. Krag says. All or nearly all patients with disease in their
lymph nodes would be eligible for sentinel node biopsy "if studies
prove there's no price paid in survival," he says.
Always consult your
physician for more information.
Online
Resources
(Our Organization
is not responsible for the content of Internet sites.)
American
Cancer Society
American
Society for Clinical Oncology
Centers
for Disease Control and Prevention (CDC)
National
Cancer Institute (NCI)
National
Institutes of Health (NIH)
National
Women's Health Information Center
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September 2003
Breast
Cancer Staging By Sentinel Node Biopsy Backed
Less
Surgery Linked to Fewer Problems
Defining
Studies Currently Underway
What
Is Sentinel Lymph Node Biopsy?
Types
of Breast Cancer Surgery
Online
Resources
What
Is Sentinel Lymph Node Biopsy?
Sentinel lymph node
biopsy is a procedure that involves injecting a dye and/or radioactive
substance near the tumor.
This injection helps
to locate the lymph node closest to the tumor (sentinel node);
the one that is most likely to have cancer cells present if
the cancer has spread.
The surgeon removes
the lymph node that absorbs the dye and radioactive substance
and sends it to the pathologist to examine it closely for the
presence of cancer cells.
Cancer cells may appear
first in the sentinel node before spreading to other parts of
the body.
Always consult your
physician for more information.
Types
of Breast Cancer Surgery
There are two types
of breast conservation (tissue-sparing) surgery. These include
a lumpectomy and a partial (segmental) mastectomy.
A lumpectomy
is the removal of the breast cancer and a portion of normal
tissue around the breast cancer lump.
The surgeon may also
remove some of the lymph nodes under the arm to determine if
the cancer has spread. The bean-shaped lymph nodes under the
arm (also called the axillary lymph glands) drain the lymphatic
vessels from the upper arms, the majority of the breast, the
neck, and the underarm regions.
Often, breast cancer
spreads to these lymph nodes, thereby entering the lymphatic
system and allowing the cancer to spread to other parts of the
body.
Radiation therapy
is often administered, following a lumpectomy, to destroy cancer
cells that may not have been removed during the lumpectomy procedure.
A partial
(segmental) mastectomy involves the removal of the
breast cancer and a larger portion of the normal breast tissue
around the breast cancer.
The surgeon may also
remove the lining over the chest muscles below the tumor and
some of the lymph nodes under the arm. The bean-shaped lymph
nodes under the arm (also called the axillary lymph glands)
drain the lymphatic vessels from the upper arms, the majority
of the breast, the neck, and the underarm regions.
Radiation therapy
may also be administered, following a partial mastectomy, to
destroy cancer cells that may not have been removed during the
partial mastectomy procedure.
During a total
(or simple) mastectomy, the surgeon removes the entire
breast (including the nipple, the areola, and most of the overlying
skin) and may also remove some of the lymph nodes under the
arm, also called the axillary lymph glands.
The bean-shaped lymph
nodes under the arm drain the lymphatic vessels from the upper
arms, the majority of the breast, the neck, and the underarm
regions.
During a modified
radical mastectomy, the surgeon removes the entire
breast (including the nipple, the areola, and the overlying
skin), some of the lymph nodes under the arm (also called the
axillary lymph glands), and the lining over the chest muscles.
In some cases, part
of the chest wall muscles is also removed.
During a radical
mastectomy, the surgeon removes the entire breast (including
the nipple, the areola, and the overlying skin), the lymph nodes
under the arm, also called the axillary lymph glands, and the
chest muscles. For many years, this was the standard operation.
However, today, a radical mastectomy is rarely performed and
is generally only recommended when the breast cancer has spread
to the chest muscles.
Always consult your
physician for more information.
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