HEREDITARY BREAST CANCER

As women get older, their chance of developing breast cancer increases.

• by the age of 30, the risk of breast cancer is 1 in 2,500
• by age 50, it is 1 in 50
• by age 70, it is 1 in 14
• by the age of 80, it is 1 in 9

Men may also develop breast cancer, but much less frequently than women.

Most breast cancer is not hereditary. Only 5-10% of all cases are due to strongly inherited factors.  Another 15-20% of cases are familial, and the remainder are sporadic.

Hereditary breast cancer can run in either the mother’s or the father’s side of the family.

A 3-generation family history is the most helpful key for determining if a cancer may hereditary.  Look for:

• early age of diagnosis (<50)
• additional relatives with breast or ovarian cancer
• breast and ovarian cancer in the same person
• multiple tumors in the same breast, or tumors in both breasts
• male breast cancer

Hereditary breast cancer is associated with mutations in two genes, BRCA1 and BRCA2, which account for about 80% of the cases of inherited breast cancer.  Other genes, as yet unidentified, probably cause the rest.

Both women and men who carry these gene mutations have an increased risk to develop breast cancer at some point during their lifetime.  The risk is increased from 11% in the general population to up to 80% in women with BRCA1 or BRCA2 mutations. People who know they carry such mutations can make informed decisions about medical care and cancer surveillance, but there is no way to prevent breast cancer at this time.

Other risk factors in addition to family history that may influence a woman’s chance to develop breast cancer are:

• age
• hormonal factors (ages at first period, birth of first child, menopause)
• number of breast biopsies and the results
• diet, exercise, alcohol intake