Risk Factors
The exact cause of breast cancer is not known, however, there are certain risk factors linked to the disease. Some are due to genetic mutations such as HER2, BRCA1 or BRCA2 genes, which may be inherited or acquired. Only about 10% of breast cancers are caused by this but 50%-60% of women with these inherited gene mutations will develop breast cancer by the age of 70. Women with close blood relatives having the disease are also at greater risk and having a mother, sister or daughter with breast cancer almost doubles the risk. The chance of developing breast cancer increases as a woman gets older and there is a slight increased risk if menstruation started before the age of 12 or menopause began after the age of 50.
Women who have had their first child after they were 30 years old or who have not had children are also slightly more at risk.
There are other risk factors that can be controlled. Most studies suggest that long-term use of hormone replacement therapy (HRT) for menopause symptoms can increase the risk of breast cancer slightly. There is a clear link between the use of alcohol and breast cancer with studies showing that consumption of 2 to 5 alcoholic drinks per day increases the risk one and a half times. There are conflicting studies regarding diet and exercise in relation to breast cancer as well as whether or not breast-feeding has an impact on risk and more research is being done in these areas. Being at risk does not indicate breast cancer and some women with one or more risk factors never develop the disease, while most women who have developed breast cancer did not appear to have any risk factors.
Next: Symptoms and Diagnosis
Related informational links:
American Cancer Society
American Cancer Society Clinical Trials Matching Service
National Cancer Institute Breast Cancer
CancerNet - A service of the National Cancer Institute
National Breast Cancer Awareness Month
Breast Cancer Net
New York Times - Breast Cancer News
CancerTrack - Tracking cancer online
Mamm Magazine online
Health Central
Breast Cancer Society of Canada