Breast cancer
Definition
Breast cancer
is a cancer that starts in the tissues of the breast.
There are two main types of breast
cancer:
- Ductal carcinoma starts in the tubes (ducts) that move milk
from the breast to the nipple. Most breast cancers are of this type.
- Lobular carcinoma
starts in parts of the breast, called lobules, that produce milk.
In rare cases, breast cancer
can start in other areas of the breast.
Many breast
cancers are sensitive to the hormone estrogen. This means that estrogen causes the breast cancer tumor
to grow. Such cancer is called estrogen receptor positive cancer or ER positive cancer.
Some women
have what's called HER2-positive breast cancer. HER2 refers to a gene that helps cells grow, divide, and repair themselves. When cells have too many copies of this gene, cells -- including cancer
cells -- grow faster. Experts think that women with HER2-positive breast cancer have a more aggressive disease
and a higher risk of recurrence than those who do not have this type.
Alternative Names
Cancer
- breast; Carcinoma - ductal; Carcinoma - lobular
Causes
Over the course of a
lifetime, one in eight women will be diagnosed with breast cancer.
Risk factors you cannot change include:
Age and gender
-- Your risk of developing breast cancer
increases as you get older. The majority of advanced breast cancer cases are found in women
over age 50. Women are 100 times more likely to get breast cancer then men.
Family history
of breast cancer
-- You may also have a higher risk for breast cancer
if you have a close relative has had breast, uterine, ovarian, or colon cancer. About 20-30% of women
with breast cancer have a family history of the disease.
Genes
-- Some people have genes that make them more prone to developing breast cancer
. The most common gene defects are found in the BRCA1 and BRCA2 genes. These genes
normally produce proteins that protect you from cancer. But if a parent passes you a defective gene, you have an increased risk for breast cancer
. Women with one of these defects have up to an 80% chance of getting breast cancer
sometime during their life.
Other genetic defects have been linked to breast cancer
, including those found in the ATM gene, the CHEK-2 gene, and the p53 tumor suppressor gene, but these are very rare.
Menstrual cycle
-- Women who get their periods early (before age 12) or went through menopause
late (after age 55) have an increased risk for breast cancer.
Other risk factors include:
Alcohol use
-- Drinking more than 1-2 glasses of alcohol a day may increase your risk for breast cancer
.
Childbirth
-- Women who have never had children
or who had them only after age 30 have an increased risk for breast cancer. Being pregnant more than once or becoming pregnant at an early age reduces your risk of breast cancer
.
DES
-- Women who took diethylstilbestrol
(DES) to prevent miscarriage may have an increased risk of breast cancer after age 40. This drug
was given to the women in the 1940s-1960s.
Hormone replacement therapy (HRT)
-- You have a
higher risk for breast cancer if you have received hormone replacement therapy for several years or more. Many women
take HRT to reduce the symptoms of menopause.
Obesity
-- Obesity
has been linked to breast cancer, although this link is controversial. The theory is that obese women
produce more estrogen, which can fuel the development of breast cancer.
Radiation
-- If you received radiation therapy as a child or young adult to treat cancer
of the chest area, you have a significantly higher risk for developing breast cancer. The younger you started such radiation
, the higher your risk -- especially if the radiation was given when a female was developing breasts.
Breast
implants, using antiperspirants, and wearing underwire bras do not raise your risk for breast cancer. There is no evidence of a
direct link between breast cancer and induced abortion or pesticides.
The National Cancer Institute
provides an online tool to help you figure out your risk of breast cancer
. See: www.cancer.gov/bcrisktool
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