Risk factors of Breast Cancer
Written by : Dr.M.D.Mazumdar, MD
The Risk Factors for Breast Cancer are many, but having one or more risk factors does not always mean that a woman will get breast cancer.
Many factors can influence these risk factors. Very often, it is seen that a woman with a number of risk factors do not get breast cancer while a woman with no apparent risk factor may suffer from it.
Even when a woman with breast cancer does have a risk factor, it is very difficult, if not impossible, to prove that her cancer is indeed a result of that particular risk factor.
Some risk factors can be changed - for example obesity and alcohol intake. But some cannot be changed, such as those that are familial or genetic. But others
Risk Factors Which Cannot be Changed
From age 30 to age 39 | 0.44% (1 in 227) |
From age 40 to age 49 | 1.49% (1 in 67) |
From age 50 to age 59 | 2.79% (1 in 36) |
From age 60 to age 70 | 3.38% (1 in 26) |
- BRCA1 / BRCA2 Genes: Women who carry mutations of BRCA1 (breast cancer gene 1) or BRCA2 (breast cancer gene 2) are at higher risk of developing both breast and ovarian cancer than women who do not have these genetic mutations.
- HER2 Gene: The HER2 (human epidermal growth factor receptor 2) is another gene which has been found to increase the risks of developing breast cancer. This gene is found on the surface of cells that plays a key role in regulating cell growth. When mutations of this gene occurs, extra HER2 recptors are formed in the breasts and ovaries, increasing the risk of developing cancers in these two organs. The drug, Herceptin, is the drug of choice used in the treatment of HER2 positive breast cancers.
- p53 Gene: Mutations of the p53 gene may not only increase the risks of developing breast cancer but also causes a more aggressive form of breast cancer in which the outcome is poorer than in other types of breast cancers.
- ATM Gene: The ATM gene normally helps repair damaged DNA. Mutations can increase the risks of breast cancer.
- CHEK2 Gene: Risks of breast cancer doubles in women who have a mutated form of this gene.
- PTEN Gene: Mutations of this gene are usually inherited. Women who have this mutated gene are at increased risk for both benign and malignant breast tumors. They may also have growths in the digestive tract, thyroid, uterus, and ovaries.

- Two or more relatives with breast or ovarian cancer.
- Breast cancer occurs before age 50 in a relative (mother, sister, grandmother or aunt) on either side of the family. The risk is higher if the mother or sister has a history of breast cancer.
- Relatives with both breast and ovarian cancer
- One or more relatives with two cancers (breast and ovarian, or two different breast cancers)
- A male relative (or relatives) with breast cancer
- A family history of breast or ovarian cancer and Ashkenazi Jewish heritage.
- A family history includes a history of diseases associated with hereditary breast cancer such as Li-Fraumeni or Cowdens Syndromes.
- Lobular carcinoma in Situ(LCIS) Although technically, LCIS is a cancer since the cells are abnormal, it is usually considered a precancerous condition since the abnormal cells do not always spread beyond the breast lobule if not treated.
- Atypical Ductal Hyperplasia (ADH)
- Atypical Lobular Hyperplasia(ALH)
- Complex fibroadenoma or Phyllodes tumor
- Sclerosing adenosis
- Dense breasts as seen on mammography
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