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
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
Susan
G. Komen Breast Cancer Foundation
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September 2003
In
This Issue:
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
Other
Resources:
St.
John's Mercy Cancer Services
Find
a St. John's Mercy Physician
Breast
Health Information
Women's
Health Information
St.
John's Mercy Classes and Programs
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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