Risk Factors for Breast Cancer
Only about 5 percent of those patients who develop breast cancer, have will have one or more identifiable genetic risk factor for breast cancer. This means majority of the breast cancers are unrelated to genetic risk factors. However if a woman inherits a genetic mutation like BRCA1 or BRCA2 the lifetime risk of development of breast cancer in that woman may be as high as 85 percent. Apart form BRCA1 and BRCA2 there are rare genetic forms of breast cancer that may be associated with mutation of the PTEN gene, ATM gene, or p53 gene giving rises to Cowden's syndrome, or ataxea-telangiextasia, or Li-Fraumeni syndrome respectively.
Family history of breast cancer
Apart from genetic mutation that increases the risk of breast cancer, presence of a family member with breast cancer would increase the risk of development of breast cancer in a woman. Unlike patients who are carriers of well-recognized genetic mutations, these woman does not have any evidence of genetic alterations that would increase the risk of breast cancer. The increased breast cancer risk in this group of women may be caused by a group of genes, which has increased predisposition to development of breast cancer. It is also difficult to separate environmental factors in these patients and how much of this increased risk is caused by common environmental factors is difficult to judge.
If a woman, has a first degree relative (mother, daughter, or sister) with diagnosis of breast cancer, the risk of that woman developing breast cancer is 1.7 times higher (called relative risk) compared to the general population. If that first-degree relative of that woman had developed breast cancer prior to the menopause, the relative risk for her would be 3 fold. On the other hand if that relative had breast cancer after menopause, the relative risk for that woman would be 1.5 fold. If that relative had developed bilateral breast cancer then the relative risk for her would be 5 fold higher. Again if that relative who developed bilateral breast cancer had developed the breast cancer prior to menopause, the relative risk for her would be 9 fold higher.
Socio Economic Status
The incidence of breast cancer is greater in women of higher socio-economic background. The relationship of breast cancer risk with socio-economic factors is most likely related, to the life style differences like age at first childbirth, and number of pregnancies.
Left Vs Right side
Left breast tend to be more involved in breast cancer compared to the right breast. The most common location of breast cancer is the upper outer quadrant.
More Resources on breast cancer