Family risk

The greatest risk factor for breast cancer is 'being female' and the second strongest is family history. If you're a younger woman with breast cancer, your specialists will be very interested in gaining a detailed family medical history, looking for incidences of certain types of cancers and the ages at diagnosis. If there appears to be a strong case for a genetic link, then your specialist team may recommend genetic testing and how the results of this could affect you, your immediate family and your children. However, very few women progress to this stage because only 5-10% of all breast cancers are inherited.

Genetic testing is carried out for a very small number of families and requires careful consideration beforehand. For more information about genetic testing, visit the site of the NZ Genetic Health Service and read more about inherited breast cancer here. Watch a NZ video about family risk of breast cancer here.

We know that two genes in particular can increase breast cancer risk: BRCA1 and BRCA2. When healthy, these two genes act as 'tumour suppressors' meaning they have a protective effect against cancer. However, if the gene(s) carry a fault, then they cannot function normally and so there is a heightened risk of breast cancer, particularly for younger women.

We have two copies of every gene. When we have children, one of those genes is passed on. If, in a parent, one of the two BRAC1 or BRAC2 genes is abnormal, then there is a 50:50 chance of the faulty gene being passed on to children.

If there appears to be a high risk within your family, identified by incidence of certain cancers in relatives/ancestors, then you may be eligible for genetic testing which will be used to determine if there is a fault in your BRAC1 or BRAC2.

There are a number of recognised risk factors for breast cancer and a good listing of these can be found on the American website.