The causes of breast cancer are not exactly known but there are risk factors that increase the chance of developing breast cancer.
Having risk factors do not mean a woman will definitely develop breast cancer, as many women who have had breast cancer did not have any apparent risk factors.
Some risk factors such as gender and age, or those related to our environment cannot be changed (non-modifiable), while others are modifiable as they are related to our lifestyle choices.
Being a woman is a risk factor for developing breast cancer. Women have a much higher chance of developing breast cancer than men due to the female hormones oestrogen and progesterone.
This risk is increased with longer hormonal exposure in women with early menarche (onset of menstruation) before the age of 12 and late menopause (after the age of 55).
Other hormonal-related factors include never having children, late childbearing (after the age of 30), and obesity, especially excessive weight gain in post-menopausal women. This risk also increases with age.
Genetic factors and family history of breast cancer, especially in a first-degree relative (mother, sister or daughter), or two or more close relatives such as cousins and the presence of genetic alterations in certain genes such as BRCA1 and BRCA2 which are associated with significant lifetime risks of breast cancer.
A past history of breast cancer, radiation exposure for medical reasons and certain benign conditions such as atypical ductal hyperplasia, atypical lobular hyperplasia or lobular carcinoma in-situ diagnosed on breast biopsy also increase the risk.
However, most women who have breast cancer have none of the above risk factors. Likewise, not possessing any of these risk factors does not mean that one will not get breast cancer. There is ongoing research to learn more about these factors, as well as ways to prevent breast cancer.
