| Breast
Cancer: |
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Breast
cancer is now the most commonly diagnosed
cancer in women. It is estimated
that more than 180,000 new cases
of invasive breast cancer will be diagnosed
in the U.S. during the next year. This will
be in addition to over 39,000 new cases
of ductal carcinoma in situ (also
called DCIS), a specific early, non-invasive
type of cancer. A woman's life-time risk
of developing breast cancer is approximately
1 in 9. Another 1,400 cases of breast cancer
will be diagnosed in men. Sadly,
over 41,000 people will die from their breast
cancer during the next year.
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It is the second leading cause of death by
cancer in women (only lung cancer kills more
women). The cancer can develop from any of the
cells that make up the breast.
The main components of the breast are:
| Lobules
- |
The
milk producing glands of the breast. |
| Ducts
- |
The
tubes through which the milk passes
to the nipple. |
| Stroma
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The
fatty tissue that surrounds the ducts
and lobules. |
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Cancer
can also involve the nipples and areola
(the darker skin around the nipple). There is
also a large and extensive lymph system in the
breast. Lymphatic vessels carry lymph
fluid (a clear fluid in which waste from tissues
and cells from the immune system are carried)
from the breast tissue to the lymph nodes.
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Where
the breast cancer occurs in the breast tissue may
have an impact on whether cancer cells can or will
spread to the various "draining" lymph
nodes. Traditionally the breast is thought to represent
five distinct zones:
|
Nipple
Upper
inner quadrant
Upper
outer quadrant
Lower
inner quadrant
Lower
outer quadrant
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Compared
to outer quandrant cancers, there is a higher
chance for the inner quadrant cancers to spread
cancer cells through the lymphatic system to the
"intramammary" (between the ribs
and the breastbone) lymph nodes. Outer quadrant
cancers most often send cancer cells to "axillary"
(in the arm pit) lymph nodes and sometimes, up
into "supraclavicular" (above
the clavicle) region.
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