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What
Is Breast Cancer?
Breast cancer is a malignant tumor that has developed from cells of the breast. A malignant
tumor is a group of cancer cells that may invade surrounding tissues or spread (metastasize) to distant areas of
the body. The disease occurs almost entirely in women, but men can get it, too. The remainder of this document refers only
to breast cancer in women. For information on breast cancer in men, see the American Cancer Society's document, "Breast Cancer in Men."
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Breast Cancer is most common in women although men can have
breast cancer it is not something a man has to worry about as often as women. Most breast cancers begin in the cells that line the ducts (ductal cancers), some begin in the cells that line
the lobules (lobular cancers), and the rest in other tissues.
Blood vessels (arteries and veins) carry plasma, red blood cells, white
blood cells, and platelets to and from the breast. Lymphatic vessels are like veins, except that they carry lymph away
from the breast, instead of blood. Lymph is a clear fluid that contains tissue fluid and waste products and immune
system cells (cells that are important in fighting infections). Lymph nodes are small bean-shaped collections of immune
system cells that are found along lymphatic vessels. Cancer cells can enter lymphatic vessels and begin to grow in lymph nodes.
This becomes important when we talk about staging.
Benign
Breast Lumps
Most breast lumps
are not cancerous, that is, they are benign. Still, many need to be biopsied (see below) to prove they are not cancer. Most
lumps turn out to be fibrocystic changes. The term "fibrocystic" refers to fibrosis and cysts. Fibrosis is the formation of
fibrous (or scar-like) tissue, and cysts are fluid-filled sacs. Fibrocystic changes can cause breast swelling and pain. This
often happens just before a period is about to begin. Your breasts may feel nodular, or lumpy, and, sometimes, you may notice
a clear or slightly cloudy nipple discharge.
Benign breast tumors such as fibroadenomas or intraductal
papillomas are abnormal growths, but they are not cancer and cannot spread outside of the breast to other organs. They
are not life threatening. Still, some benign breast conditions such as papillomas and atypical hyperplasia are important
because women with these conditions have a higher risk of developing breast cancer.
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Breast profile:
A Ducts
B Lobules
C Dilated section of duct to hold
milk
D Nipple
E Fat
F Pectoralis major muscle
G Chest wall/rib cage
Enlargement
A
Normal duct cells
B Basement membrane
C Lumen (center of duct) |
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