Risk factors for breast cancer

Risk factors are the things that raise your chance of getting a disease. There are various risk factors that may contribute to the development of breast cancer. Some have a stronger link to breast cancer than others. The following are some of the most significant risk factors for developing breast cancer.

• Gender. Approximately half of all women who develop breast cancer have no identifiable risk factor other than being female and aging. This means it is very important for every woman to be aware of this disease and to try to ensure that they find it early. Although men do get breast cancer, the main risk factor is being female.
• Age. Besides being female, the greatest risk factor for breast cancer is age: older women are much more likely to get breast cancer. Breast cancer is much less frequent among younger women, the earliest diagnoses usually being made at around 25 years.
• Personal history of breast cancer. Having had breast cancer puts a woman at higher risk for developing it again.
• Family history of cancer. The risk of breast cancer increases if a woman has a first-degree relative (mother, sister, or daughter) who had breast or ovarian cancer.
• High breast tissue density. The higher the breast tissue density, the greater the risk for breast cancer. Breast tissue density is generally higher when the breast has more ducts and lobules versus fat.
• Breast hyperplasia. Hyperplasia is an increase in the growth of cells in a tissue, such as breast tissue. Breast hyperplasia can be detected only by taking a sample of the breast tissue and examining it under a microscope. Breast hyperplasia increases a woman's chance of developing breast cancer.
• Long-term estrogen exposure. Breast cancer is clearly related to the sex hormones. In some types of breast cancers, the presence of the female sex hormone estrogen causes the cancer cells to grow and divide rapidly. During puberty, estrogen levels dramatically increase. During menopause, estrogen levels decrease. The longer the time the breasts are exposed to estrogen, the higher the risk of developing breast cancer. Therefore, breast cancer risk may be higher in women who started menstruating before age 12 or in women who went through menopause after age 55. Risk may also be higher in women who have taken oral contraceptives or hormone replacement therapy (HRT). Since estrogen strengthens bones, women with high bone mass may have a higher risk of breast cancer.
• Menopausal hormone replacement therapy. Risk may also be higher in women who have taken certain types of hormone replacement therapy (HRT) over several years or more. This type of therapy should not be confused with hormonal treatment, which is used to treat some breast cancers.
• Not having children or having first child after age 30. These factors may increase a woman's risk of developing breast cancer, because estrogen levels are lower during pregnancy. Not breast-feeding may also be a risk factor.
• Radiation exposure. Prior radiation to the chest area increases the risk for breast cancer.
• Ashkenazi Jewish heritage. Women of this heritage may have an increased risk due to possible inherited gene mutations (such as in the BRCA1 or BRCA2 genes).
• Genetics. There are inherited genetic alterations that increase the risk of breast cancer. Alterations in the BRCA1 and BRCA2 genes are found in about 5% to 10% of breast cancer cases. Women with alterations in these genes have up to an 85% chance of developing breast cancer in their lifetime.

Other possible risk factors for breast cancer may include:

• Diet. A good, balanced diet is important. There is some evidence to suggest that animal fat can increase the risk of breast cancer. Being overweight may also increase breast cancer risk. In addition, research suggests that too much alcohol can increase the risk of breast cancer. Women who drink one or more alcoholic beverages per day may be more likely to develop invasive breast cancer than women who do not drink alcohol.
• Environmental factors. As with many other cancers, being around certain environmental factors, such as radiation, increases the risk of breast cancer. Thus, women who were exposed to high levels of radiation, such as those who had radiation to treat other cancers as a child, are at a higher risk of developing breast cancer.
• Smoking. Smoking can lead to various types of cancers, and women who smoke have poorer health in general. If you smoke, you should quit now. Not smoking will enable you to handle cancer treatment better.

Remember, though, that approximately half of all women who develop breast cancer have no identifiable risk factor other than being female and aging.