In certain cases, where family members are at high risk of breast cancer we may be able to identify a fault in one of the two known breast cancer genes, BRCA1 and BRCA2. There are probably other genes not yet identified which may contribute towards breast cancer.
If a gene fault is identified it allows us to offer a blood test to other family members to see whether or not they have inherited the same faulty gene. A person who has inherited the fault will be at high risk (probably between 50-80%) of developing breast cancer in their lifetime. However, we know that not everyone with the inherited gene fault does develop cancer and we do not know why that is the case. A person who is found not to have inherited the BRCA1 or BRCA2 gene fault present in their family will no longer be considered to be at high risk, and their children will not be at risk of carrying the familial gene alteration. A person who is found to have inherited the familial gene fault may be offered increased surveillance or preventive surgery.
Testing for a gene fault has many implications for different family members and should be considered carefully.
Breast self-examination and being breast aware may be beneficial for women. There are other possible protective factors which may reduce a woman's risk of developing breast cancer. It is thought that having children young and breast feeding may be helpful. A diet with plenty of fresh fruit and vegetables, a relatively low fat intake, regular exercise and avoiding excessive alcohol may reduce the risk of breast cancer. Not smoking lowers the risk of developing many cancers.