Breast cancer is the top cancer in women both in the developed and the developing countries. In particular, the incidence of breast cancer is increasing in the developing countries due to increased life expectancy, increased urbanization and the adoption of western lifestyles.
The information on this webpage is provided for general education only. Individuals should consult a qualified health care provider for professional medical advice, diagnoses and treatment of a medical or health condition.
Breast Cancer and Risk Factors
When you're told that your loved one has breast cancer, it's natural to wonder what may have caused the disease. However, no one knows the exact causes of breast cancer. Doctors seldom know why one woman develops breast cancer and another doesn't.
Doctors do know that bumping, bruising, or touching the breast does not cause cancer. Also, it is not contagious so you can't catch it from another person.
Doctors also know that women with certain risk factors are more likely than others to develop breast cancer. A risk factor is something that may increase the chance of getting a disease.
Although some risk factors (such as drinking alcohol) can be avoided, most risk factors (such as having a family history of breast cancer) can't be avoided.
Studies have found the following risk factors for breast cancer:
Age
The chance of getting breast cancer increases as you get older. Most women are over 60 years old when they are diagnosed.
Personal Health History
Having breast cancer in one breast increases the risk of getting cancer in the other breast. Also, having certain types of abnormal breast cells (atypical hyperplasia, lobular carcinoma in situ [LCIS], or ductal carcinoma in situ [DCIS]) increases the risk of invasive breast cancer. These conditions are found with a breast biopsy.
Family Health History
Your risk of breast cancer is higher if your mother, father, sister, or daughter had breast cancer. The risk is even higher if your family member had breast cancer before age 50. Having other relatives (in either your mother's or father's family) with breast cancer or ovarian cancer may also increase your risk.
Certain Genome Changes
Changes in certain genes, such as BRCA1 or BRCA2, substantially increase the risk of breast cancer. Tests can sometimes show the presence of these rare, specific gene changes in families with many women who have had breast cancer, and health care providers may suggest ways to try to reduce the risk of breast cancer or to improve the detection of this disease in women who have these genetic changes.
Radiation Therapy in the Chest
Women who had radiation therapy in the chest (including the breasts) before age 30 are at an increased risk of breast cancer. This includes women treated with radiation for Hodgkin lymphoma. Studies show that the younger a woman was when she received radiation treatment, the higher her risk of breast cancer later in life.
Reproductive and Menstrual History
The older a woman is when she has her first child, the greater her chance of breast cancer.
Women who never had children are at an increased risk of breast cancer.
Women who had their first menstrual period before age 12 are at an increased risk of breast cancer.
Women who went through menopause after age 55 are at an increased risk of breast cancer.
Women who take menopausal hormone therapy for many years have an increased risk of breast cancer.
Breast Density
Breasts appear on a mammogram (breast x-ray) as having areas of dense and fatty (not dense) tissue. Women whose mammograms show a larger area of dense tissue than the mammograms of women of the same age are at increased risk of breast cancer.
Being Overweight or Obese After Menopause
The chance of getting breast cancer after menopause is higher in women who are overweight or obese.
Lack of Physical Activity
Women who are physically inactive throughout life may have an increased risk of breast cancer.
Drinking Alcohol
Studies suggest that the more alcohol a woman drinks, the greater her risk of breast cancer.
Having a risk factor does not mean that a woman will get breast cancer. Most women who have risk factors never develop breast cancer.
Many other possible risk factors have been studied. For example, researchers are studying whether women who have a diet high in fat or who are exposed to certain substances in the environment have an increased risk of breast cancer. Researchers continue to study these and other possible risk factors
Reference: World Health Organization (http://www.who.int/cancer/detection/breastcancer/en/) acessed 30 June 2011.
