About Breast Cancer: Get the Facts
What Is Breast Cancer?
As you may have learned from the about cancer page, cancer occurs when abnormal cells divide uncontrollably. When this happens, a
tumor
may form. Breast cancer occurs when a tumor forms inside the breast.
Sometimes the cancer can spread, or
metastasize
, outside of the breast and into other body parts. If breast cancer spreads, it
commonly spreads to the
lymph nodes
, bones, lung, brain and/or liver.
There are different types of breast cancers. Most types of breast cancer originate
in the milk
ducts
. These are called ductal
carcinomas
. Some types of breast cancer originate in the breast
lobules
. These are called lobular carcinomas.
Breast cancer is considered
noninvasive
, or
in situ
, when it stays inside the ducts DCIS or lobules LCIS. If the cancer grows into
surrounding breast tissue or spreads to other areas of the body, it is considered
invasive
.
Breast Cancer Statistics and Facts
According to the American Cancer Society:
- Next to skin cancer, "breast cancer is the most common cancer among women, accounting
for nearly 1 in 3 cancers diagnosed in U.S. women."
- In 2005, approximately 211,000 new invasive breast cancer cases were expected to
occur, and approximately 40,000 women were expected to die from breast cancer
- The risk of breast cancer and death due to breast cancer increases with age; from
1998-2002, "95% of new cases and 97% of breast cancer deaths occurred in women aged
40 and older."
What causes breast cancer is unknown. However, there may be factors that may put people
at an increased risk for breast cancer.
Learn more about breast cancer:
