The cause of breast cancer is unknown. In fact, it is thought that there is not one single cause of breast cancer. It is more likely that a number of factors, some known and many unknown, may work together to trigger the development of breast cancer.
Doctors have identified several factors that can indicate that a woman may have an increased chance of developing breast cancer. However, having one or even several of these characteristics does not mean that a woman is certain or even likely to develop breast cancer. |
Knowing the risks
Gender and age
The most important risk factors for breast cancer are being a woman and getting older. Breast cancer is predominantly a disease of women over 50 years of age, although it can occur in women under this age. Therefore increasing age is considered a major risk factor for developing breast cancer.
Breast changes
A biopsy confirming benign disease with atypical cells can also indicate a risk of breast cancer. This means that while cancer is not present, the atypical cells indicate an increased risk of breast cancer.
Family history
The degree of this increased risk can be very low to moderately high depending on several factors. These include:
|
- the number of relatives affected
- the age of relatives at diagnosis
- the type of breast cancer
- whether breast cancer was bilateral (in both breasts)
- breast cancer in a male relative
- a family history of ovarian cancer
|
Genetic
Recently a genetic link to breast cancer has been found. There are rare inherited faulty genes that occur in about 5% of all breast cancers. In these cases the life-time risk of developing breast cancer is considered to be significantly greater.
Cancer history
A history of primary cancer of the ovary, uterus, bone or soft tissue is considered a risk factor for developing breast cancer.
Previous breast cancer
Women who have had breast cancer do have a higher chance of developing a new cancer in the same breast or in the previously unaffected breast.
Behavioural and lifestyle factors
Some other factors which may also influence the development of breast cancer are:
|
- never having children or having the first full-term pregnancy after the age of 30;
- a diet high in animal fat, and low in fibre, fruit & vegetables;
- obesity in post menopausal women;
- early menarche [start of first period] and late menopause;
- high intake of alcohol;
- long term smoking;
- inactive lifestyle;
- taking hormone replacement therapy or a hormone drug
|
Breast cancer is more common in women of higher rather than lower socio-economic status.
However, all of these factors together account for no more than 30% of breast cancers.
Any woman who identifies with one or more of the above factors should discuss her concerns with her doctor. |
|
