family history of breast cancer

If a woman with a family history of breast cancer wishes to clarify her genetic risk or that of her family, health professionals should discuss referral to specialist genetic services for advice, appropriate counselling and management. For more information, refer to Advice about familial aspects of breast cancer and ovarian cancer:A guide for health professionals.28

A history of breast and/or ovarian cancer in one or more first-degree relatives may be the strongest risk factor for younger women,23 particularly if the affected relative was younger than 50 years at diagnosis.27 In one Australian case-control study of women aged younger than 40, 12% of women with breast cancer compared with 5% of controls reported a history of the disease in a first-degree relative of any age.23 Family history taking should include both the maternal and paternal sides of a family.

Several genes are associated with a high risk of breast or ovarian cancer. It is estimated that between 1% and 5% of all breast and ovarian cancers involve the inheritance of a mutated gene.28 In younger women, the proportion of breast and ovarian cancers believed to involve an inherited mutated gene is higher.29 International data from samples of women not selected for family history suggest the prevalence of a BRCA1 mutation in women diagnosed with breast
cancer before age 35 is approximately 6-11%.29-31

In some circumstances,women with a very strong family history, or who are found by genetic testing to have inherited a mutated copy of a high-risk gene, may wish to explore possibilities for reducing their risk of developing breast cancer, such as prophylactic mastectomy and/or prophylactic bilateral salpingooophorectomy. Women who are at significantly increased risk of developing breast cancer should be referred for appropriate counselling before any therapeutic decisions are made.
Women with a family history of breast cancer may experience significant levels of distress. One study of women who had one or more first-degree relatives with breast cancer found that 27% of these women had a level of psychological distress consistent with the need for counselling.32 The Psychosocial clinical practice guidelines provide examples of questions health professionals can use to screen women who may be experiencing psychological distress.33