Family History

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The lifetime risk of developing breast cancer for a woman living in the United Kingdom is one in twelve. Twenty five thousand new cases are diagnosed each year, most of whom are over the age of fifty. Less than five per cent of breast cancers are due to an inherited gene defect. A positive family history is therefore more likely to occur by chance, or being exposed to the same environmental factors, rather than due to a genetic abnormality. Specific cancer genes have been identified that may increase the risk of developing cancer. The two most important genetic abnormalities in the context of breast cancer are BRCA-1 and BRCA-2. Other genes that can affect breast cancer risk include p53 and AT. Patients with BRCA-1 mutations, for example, commonly develop breast and ovarian cancer. Women with a strong family history should be assessed for relative risks of developing breast cancer in a specialist clinic to determine further management and special screening.

Who should be followed up?

Many patients who have a family history of breast cancer do not have a genetic abnormality. Only a minority of all breast cancers diagnosed has a genetic origin. Most breast cancers with genetic basis are of early age of onset.

The criteria listed on this page are used to select women who are at thigh risk that would be advised to attend for assessment and continued follow-up in a family history. At the first visit, a detailed medical and family history will be taken to assess clinical risk. Women will be examined, and investigations performed where required. The results of mammography and breast ultrasound examination are usually available immediately. If further tests are required as a result of imagining investigations, these will also be carried out at the same visit.

Patients with a strong family history will be counselled and advised of their risks of developing breast cancer. Women who do not have an increased lifetime risk of greater than 1:8 do not usually require special follow-up. Where appropriate, arrangements can be made for women at significant risk to attend a specialist genetics clinic.

Indications for assessment and follow-up of family history patients in high risk clinics

• One first degree relative with breast cancer diagnosed before the age of 40

• Two first or second degree relatives on the same side of the family diagnosed with breast cancer before the age of 60

• Two first or second degree relatives on the same side of the family with breast and ovarian cancer at any age (a single relative with breast and ovarian cancer fulfils this criterion)

• Three first or second-degree relatives diagnosed with breast cancer under the age of 70 years.

• Four or more members on the same side of the family with breast cancer diagnosed at any age.

• First or second-degree relatives of Ashkenazi Jewish women with breast or ovarian cancer.

• First degree relatives with bilateral breast cancer.

• First degree relative of male breast cancer.

• Family members of defined cancer risk genes eg BRCA-1 and BRCA-2.

Age to start follow-up

Women who are at high risk of breast cancer from a significant family history should commence special screening at the age of 35 years. In patients whose relatives had the diagnosis of breast cancer made under the age of 35 years, mammographic screening should commence at 30 years of age, with clinical examination starting five years before the age of diagnosis of the youngest relative.

Frequency of follow-up

Annual clinical examination and annual mammograms should be offered until the age of 50 years. After the age of 50 years, women who do not have a genetic abnormality can be screened every 18 months with clinical examination and mammography. Over the age of 50 years, mammograms are more sensitive and the screening interval could be increased to reduce the total number of mammograms an individual woman will require in her lifetime. Women with a known genetic defect will continue to be screened annually.

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