Is breast cancer hereditary?

Breast cancer is hereditary. However, hereditary breast cancer only accounts for around five to ten per cent of patients who contract the disease. In the remaining 90 to 95 per cent of cases, the disease has other causes or develops for no apparent reason.

Genetic alterations as a cause for hereditary breast cancer

Hereditary breast cancer is primarily caused by alterations – mutations – in breast cancer genes such as BRCA1 and BRCA2. The abbreviation BRCA stands for BReast CAncer. Large-scale studies of families with an above-average incidence of breast cancer show that, in addition to these genes, further changes in genetic material are responsible for increasing the risk of breast cancer.

Indications of an increased risk of hereditary breast cancer

The following factors point to an increased familial incidence and a possible increased risk of breast cancer [inclusion criteria specified in the Collaborative Research Project for Familial Breast and Ovarian Cancer (Verbundprojekt Familiärer Brust- und Eierstockkrebs) initiated by the German Cancer Aid Organisation (Deutsche Krebshilfe)]:

• At least two females in the family (mother, sister, daughter or you yourself) have had breast or ovarian cancer, one of whom was younger than 50 at the time of contracting the disease.
  
• One female in the family (mother, sister, daughter or you yourself) has contracted unilateral breast cancer at the age of 30 or younger.
  
• One female in the family (mother, sister, daughter or you yourself) has contracted bilateral breast cancer at the age of 40 or younger.
  
• One female in the family (mother, sister, daughter or you yourself) has contracted breast or ovarian cancer at some time in the past.
  
• A male relative has developed breast cancer at some time in the past.
  

Counselling centres for familial breast cancer

Women with an increased risk of hereditary breast should seek advice from their doctor. They may need to be referred to a special counselling centre. In Germany, there are several familial breast cancer centres. In addition to offering advice, these centres also carry out genetic testing aimed at detecting any possible changes in the BRCA1 and BRCA2 genes. The addresses and telephone numbers of the centres specialising in familial breast and ovarian cancer can be found under the menu item “Breast cancer centres”.