What is breast cancer?
The basics.
In breast cancer, certain cells in the breast grow uncontrollably, forming a solid
mass called a tumor. Breast cancer
occurs in 3 basic types: early-stage,
metastatic, and
recurrent:
- In early-stage breast cancer, the tumor is confined to the place it started. It
may not have spread at all, or it may have spread to the lymph nodes
- In metastatic breast cancer, the disease has spread from its original location
to other parts of the body
- A breast cancer is called recurrent if it returns in a person who seemed to be disease-free after treatment
Most of the lumps that women find in the breast turn out not to be cancerous. These
non-cancerous abnormalities are called benign.
Sometimes the diagnosis isn’t clear right
away. To know for sure whether or not a problem with the breast is a tumor, breast
tissue must be examined under a microscope by a doctor called a
pathologist.
In some women, the key female hormones,
estrogen and
progesterone, promote the growth of certain types of breast cancer cells.
But not all breast cancers are caused by excess hormones.
What are the parts of the human breast?
The breast is an organ for making milk. To make a substance, the human body uses
glands. The female breast is mostly made up of glands called
lobules that make milk, as well as tiny tubes called
ducts that carry milk from the lobules to the nipples. Also in the
breast is a fatty tissue called
stroma that surrounds the lobules, ducts, blood vessels, and lymphatic vessels.
Usually, breast cancer begins in the cells of the ducts. Sometimes, however, breast
cancer starts in the lobules or other tissues.
How common is breast cancer?
Breast cancer is the second most common cancer among U.S. women, after cancers of
the skin. There are currently about 2.5 million breast cancer survivors
in the U.S., including women still being treated and those who have completed treatment.
Breast cancer by the numbers.
In 2009, the American Cancer Society’s annual projections said that:
About 192,370 new cases of
invasive (metastatic)
breast cancer would be diagnosed in women
- About 62,280 new cases of carcinoma in situ (CIS) would be diagnosed. CIS is non-invasive
and is the earliest form of breast cancer
- About 40,170 women would die from breast cancer
Currently, a woman’s chance of developing invasive (metastatic)
breast cancer at some point in her life is less than 1 in 8 (12%). Her
chance of dying from breast cancer is about 1 in 35 (3%).
Reasons to look forward with hope.
Incidences of breast cancer have been decreasing since 1999, and deaths due to breast
cancer have been decreasing since 1990, thanks to earlier detection and improved
treatment.
With more knowledge and support available to women than ever before, no one who
gets cancer should have to face it by themselves.
What are the types of breast cancer?
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