Reducing Your Risk

Women who have significant risk factors for breast cancer should consider risk reduction strategies that can help her avoid developing the disease. Women who benefit most from these strategies are those who have a family history of breast cancer in a mother or sister, those with a breast biopsy showing either “atypical hyperplasia” or “lobular carcinoma in situ,” (LCIS) and those who are carriers of the BRCA 1 or 2 gene mutation. A cancer specialist can help her decide if some type of preventive measures are appropriate for her. Options currently available are both medical and surgical.

Tamoxifen or Raloxifene

These estrogen blocking drugs have been shown to significantly decrease the risk of developing breast cancer in high risk women. Each is a pill taken daily for 5 years and they essentially make the breast uninviting to a developing cancer by blocking one of the cancer’s primary growth factors. Side effects that may be experienced include hot flashes and a small risk of uterine cancer and blood clots.  Tamoxifen can be used in both premenopausal as well as post menopausal women, but roloxifene is only appropriate in post menopausal women.   Many women have taken raloxifene (Evista) for its known bone building effects and it seems to be particularly well tolerated.  A new class of estrogen modulating drugs, the aromatase inhibitors, (Femara, Arimidex) show great promise as a preventative agent in post menopausal women, and a national trial testing this drug for that purpose is planned.

Prophylactic Mastectomy

This option is appropriate only after careful consideration of its attendant risks, both physical and emotional, along with a realistic discussion of its degree of benefit in reducing a woman’s chance of developing breast cancer. Clearly, women at highest risk are those who stand the most to gain from this preventative measure.

Carriers of the BRCA 1 or 2 gene mutations have an up to 85% lifetime risk of developing breast cancer. Prophylactic mastectomy reduces this risk by about 90%. Prophylactic oophorectomy further reduces their risk as detailed below.

Women who have lesser risk factors, such as a strong family history of breast cancer but without a genetic mutation, may also benefit from prophylactic mastectomy, but the absolute degree of the benefit is less. These women should be carefully counseled regarding non-surgical options for risk management. But, if the anxiety produced by managing her risk outweighs the benefit of preserving her breasts, prophylactic mastectomy is a reasonable way to provide her with the assurance she needs to get on with her life.

Prophylactic Oophorectomy

In women carrying the BRCA 1 or 2 gene mutation, surgical removal of the ovaries reduces the incidence of breast cancer by at least 50%. This procedure in combination with a close breast cancer surveillance program for early detection gives these high risk women a realistic option for managing their risk without resorting to mastectomy. High risk women who don’t have a genetic mutation do not enjoy the same breast cancer protection from this procedure so they are not routinely offered it.

Lifestyle Choices

In general, women who maintain ideal body weight have a lower incidence of breast cancer. This effect probably operates through lowering the amount of estrogen that we know is produced by fatty tissue. Similarly, taking hormone replacement after menopause has been shown in a recent large clinical trial to increase a woman’s risk of developing breast cancer. The number of breast cancer events in this trial was small but the relationship is undeniable. Given this information, those women who already have significant risk factors for breast cancer may want to avoid even the small additional risk that hormone replacement therapy confers.

Dietary choices can also impact the incidence of cancer in general, though this relationship is less well understood. A diet rich in green leafy vegetables, which contain beta carotenes, seems to protect against a number of cancers. Similarly, soy based diets are associated with low rates of cancer overall, though there is some controversy regarding its use in preventing breast cancer as soy is a phytoestrogen and may hypothetically provide a growth factor for this type of cancer. Moderate alcohol consumption has been linked to an increased incidence of breast cancer, but this risk may be mitigated  by ensuring an adequate intake of folate, a B vitamin found in whole grains. A number of other nutritional therapies aimed at cancer risk reduction are very provocative but rigorous scientific testing of these therapies has not yet been done. Fortunately, this is an area of emerging scientific interest and we will be hearing more about clinical trials involving natural therapies in the future.

Copyright 2008 by Janet Grange, MD