The important risk factors are associated with first degree relatives (mother, sister, daughter), especially if they have had early onset breast cancer (that is, breast cancer under 50 years, bilateral breast cancer, or a family history of ovarian cancer). Other patterns in family history may strongly suggest an inherited gene abnormality that is independent of normal aging and is associated with a relatively higher risk of breast cancer. The following signs suggest that there may be an inherited gene abnormality in your family:
- Having a mother, sister, or daughter with breast cancer
- Having multiple generations of family members affected by breast or ovarian cancer
- Having relatives who were diagnosed with breast cancer at a young age (under 50 years of age)
- Having relatives who had both breasts affected by cancer
We suggest that women who are under 40 years when diagnosed, or have a strong family history of breast or ovarian cancer see one of the genetic counselors.
Personal history of breast cancer
If you have had cancer in one breast you have an increased risk of developing cancer in the other breast. This risk can be reduced with drugs like tamoxifen, but the bottom line is that women who have had cancer in one breast should be followed very closely so that if a cancer develops in the other breast it can be caught early.
Most breast biopsies are benign, and do not influence future risk for breast cancer. However, if a woman had a previous biopsy that showed either atypical changes or lobular carcinoma in situ, her risk for breast cancer is increased. These women should seek the guidance of a physician knowledgeable in diseases of the breast. Many of these women would benefit from risk reduction medication such as Tamoxifen. They also require careful long-term follow-up.
Prolonged exposure to estrogen
Prolonged exposure to the combination of estrogen combined with progesterone increases the risk of developing breast cancer. The risk associated with prolonged use of estrogen alone has yet to be defined, but probably will prove to be less than that for combined therapy. Short term replacement therapy for the treatment of menopausal symptoms seems safe. Women who can get by without replacement therapy should do so, but don’t forget to have your bone density checked. Women who choose to take replacement therapy for control of symptoms should try to get by on the lowest dose of estrogen for the shortest period of time.
Other risk factors:
- Never having had a full-term pregnancy
- Late menopause or early menstruation
- First full-term pregnancy after age 30 years
- More than two alcoholic drinks per week