Brest Cancer Risk Factors
Breast cancer begins in the breast. There are different types of breast cancer depending on which cells turn into cancer. The breast is made of three main components: the connective tissue, ducts and lobules. The majority of these types of cancer start in the lobules or the ducts of the breast. The lobules are responsible for milk production, the ducts are responsible for movement of milk to the nipple and the connective tissue holds everything together. Breast cancer also has the ability to spread through the blood and lymph vessels to other parts of the body; this process is known as metastasis. So, what are breast cancer risk factors?
A risk factor is something (behavior, condition, substance) that increases the risk of developing breast cancer. In most cases, it develops due to the result of many risk factors. Below we will discuss them in detail, and also touch upon prevention strategies.
Risk Factors for Breast Cancer
Various risk factors for the development of breast cancer have been identified, including:
- Being female – most of these cancers develop in women, due to the exposure of the breast tissue to estrogen and progesterone. Estrogen, in particular, has been associated with the development and growth of certain breast cancers.
- Living in a developed nation – this cancer is more common in developed countries, including Canada and the U.S.
- Increasing age – the risk increases with age, with most cancers being diagnosed in women between the ages of 50 and 69.
- Being of Ashkenazi Jewish decent – Ashkenazi women are at an increased risk. This is due to the fact that BRCA1 and BRCA2 gene mutations are more common in this population.
- Having a personal history of breast cancer – women who have previously had this cancer are at an increased risk of developing it again. It may develop in the same breast or in the other one.
- Having atypical hyperplasia – having this benign breast condition that involves a greater number of atypical cells in the breast increases one's risk.
- Having a family history of breast cancer – having one or more close blood relatives who have had this cancer increases the risk of developing breast cancer.
The risk of developing breast cancer is higher in the following situations:
- A first-degree relative (mother, daughter, sister) having had breast cancer, especially if they received their diagnosis prior to menopause.
- A second-degree relative (niece, aunt, grandmother) from either parental side having had breast cancer.
- A blood relative having had breast cancer in both breasts, before menopause.
- Two or more blood relatives having had breast or ovarian cancer.
- A blood relative having had both breast and ovarian cancer.
- A male blood relative having had breast cancer.
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- Having a gene mutation – women with inherited gene mutations, including BRCA1 and BRCA2, are at an increased risk.
- Having certain genetic conditions – certain rare genetic conditions, including Li-Fraumeni syndrome, ataxia telangiectasis (AT), Cowden syndrome and Peutz-Jeghers syndrome, have been linked to an increased risk of developing breast cancer.
- Having dense breasts – having dense breasts increases the risk of breast cancer as dense breasts are composed of more connective tissue, glands and ducts than fatty tissue. Having dense breasts also makes it harder to see tumors on mammograms.
- Early menstrual periods and/or delayed menopause – starting menstrual periods before the age of 12 and/or starting menopause after the age of 55 exposes a woman to hormones for a longer period of time and increases the risk of developing breast cancer.
- Reproductive history – never having a full-term pregnancy, having a first pregnancy after the age of 30 and/or not breastfeeding increases the risk of developing this cancer.
- Oral contraceptive use – using oral contraceptives that have both estrogen and progesterone slightly increases the risk. This is especially true for women who have used oral contraceptives for over 10 years
- Hormone replacement therapy – using hormone replacement therapy (HRT) for a prolonged period of time increases the risk of developing breast cancer. This is especially true for combined HRT that uses both estrogen and progestin.
- Previous radiation therapy – women who have undergone radiation therapy to the chest or breast area before the age of 30 have an increased risk of developing this cancer.
- Taking the medication diethylstilbestrol (DES) – this medication was given to some pregnant women between 1940 and 1971 in the U.S. to prevent miscarriages. Women, and women whose mothers have taken this medication, are at an increased risk.
- Consuming alcohol – drinking alcohol, even at low levels, increases the risk of developing this cancer. This risk increases with increasing amounts of consumption.
- Being obese – obesity increases the risk of developing breast cancer in post-menopausal women.
- Leading a sedentary lifestyle – being physically inactive increases the risk of developing this cancer in both premenopausal and post-menopausal women.
- Having a higher socioeconomic status – the risk of developing this cancer is slightly higher in women who have higher incomes. This may be the result of having no children, or having them later in life due to career trajectory.
- Having a tall adult height – taller women have a slightly higher risk of developing breast cancer after menopause.
Possible risk factors for the development have also been identified, including:
- Adult weight gain.
- Smoking and exposure to second-hand smoke.
- Higher birth weight.
- Working night shifts.
- Certain non-cancerous breast conditions (fibrocystic breast changes, complex fibroadenoma, papillomatosis, sclerosing adenosis, radial scar).
Prevention of Breast Cancer
Research has shown that lifestyle changes can help decrease the risk of developing breast cancer, even in women who are at a high risk. Simple changes you can make to lower your risk include:
- Minimizing or avoiding alcohol consumption.
- Maintaining a healthy weight.
- Engaging in regular physical activity.
- Limiting hormone replacement therapy after menopause.
There are numerous risk factors for developing breast cancer. While you can change some of these risk factors, there are some that you have no control over. However, research has shown that making simple lifestyle changes can help to lower your risk of developing breast cancer, even if you are at heightened risk.