Mastectomies to Prevent Cancer

Prophylactic or Optional Mastectomies

By: Diana Zuckerman, PhD

Every year, thousands of women choose to undergo a mastectomy when lumpectomy would be an equally effective option for them. Some women choose a bilateral mastectomy when there is cancer in only one breast. Even women who do not have breast cancer may undergo mastectomies as a preventive measure because of their high risk of breast cancer.

Helping patients make an informed decision about whether to have a mastectomy is an important aspect of the physician-patient relationship. Unfortunately, many patients are not able to get the information they need from their physicians. A patient who is seriously considering a mastectomy or bilateral mastectomy that is not medically necessary may be basing her decision more on fear than on information. They may benefit from unbiased information, counseling, or from a second opinion before making a final decision.

The purpose of this article is to provide information that patients and family members can use to help them discuss their options with their physicians.

Gene Mutations that Increase the Risk of Breast Cancer (BRCA1 and BRCA2)

Women with known mutations in the BRCA1 and BRCA2 genes have a lifetime risk of breast cancer ranging from 40% to 85%, compared to 12% for women in the general population.1 Women with BRCA1 or BRCA2 mutations often develop breast cancer before age 50 and have a high risk of bilateral breast cancer and ovarian cancer.2 Removing breasts with no sign of cancer is called a prophylactic (preventive) mastectomy. Prophylactic mastectomy and prophylactic oophorectomy (removal of the ovaries) have both been shown to greatly reduce—but not eliminate—the risk of breast cancer in BRCA mutation carriers.1

Among women with strong family histories of breast cancer, individuals of Ashkenazi Jewish descent have an 8 times greater frequency of carrying these mutations in BRCA1 or BRCA2 compared with other women.3

Lumpectomy with radiation therapy is just as effective for preventing in-breast tumor recurrence in patients with BRCA mutations as it is for other women. Questions remain, however, about how other adjuvant treatments (such as chemotherapy) affect survival of women with these gene mutations.4

For women with the BRCA1 or BRCA2 genes, it is important to remember that the risk of breast cancer in the next 5 or 10 years is much lower than the lifetime risk of breast cancer. For example, the risk of breast cancer in her 20’s is very low, even with BRCA1 (less than 3%) or BRCA2 (approximately 1%). For a 30-year old woman, the risk by age 39 is higher (10% for women with BRCA1 and 8% for BRCA2). For a 40-year-old woman, the risk by age 49 is 16% for women with BRCA1 and 13% for women with BRCA2.3 Although these 10-year risk levels are much higher than for most women, they are much lower than the life-time risk that is so frightening. It is also important to remember that cancer treatments and prevention strategies are improving, so the risks of cancer may decrease and the survival rates are improving.

Non-Surgical Alternatives to Prophylactic Mastectomies

Many women who are at high risk for breast cancer consider having a prophylactic mastectomy to reduce their future cancer risk. Prophylactic mastectomies can prevent breast cancer, but many women who undergo prophylactic mastectomies would never have developed breast cancer, even without the surgery.

This is a decision that women need to make for themselves, but to make that decision they need a clear understanding of the risks and benefits as well as alternative strategies that also reduce risk.

Tamoxifen and raloxifene have both been shown to reduce the risk of breast cancer for women who have not had cancer but are at greater risk. However, it is not yet known if these drugs can prevent breast cancer for women with BRCA1 or BRCA2 mutations.

For women at high risk of breast cancer for any reason, mammography screening at a young age and annual breast MRIs are alternatives to prophylactic mastectomy. MRIs are more accurate than mammograms for young women and women with dense breast tissue.

Research indicates that a low-fat diet, weight control, and exercise may reduce the risk of breast cancer for all women, including women at high risk and women who previously were treated for breast cancer.4, 5

References

1 Schrag D, Kuntz KM, Garber JE, Weeks JC. Decision analysis – effects of prophylactic mastectomy and oophorectomy on life expectancy among women with BRCA1 or BRCA2 mutations. New England Journal of Medicine. 1997;337(6):434.

2 Rubinstein, WS. Hereditary breast cancer in Jews. Familial Cancer. 2004;3:249-257.

3 Chen S, Iversen ES, Friebel T, Finkelstein D, Weber BL, Eisen A. et al. Characterization of BRCA 1 and BRCA 2 mutations in a large United States sample. Journal of Clinical Oncology. 2006;24(6):863-869.

4 Breast Cancer (PDQ®): Treatment. National Cancer Institute. http://www.cancer.gov/cancertopics/pdq/treatment/breast/HealthProfessional/

5 Prentice RL, Caan B, Chlebowski RT, Patterson R, Kuller LH, Ockene JK, et al., The women’s health initiative randomized controlled dietary modification trial. JAMA. 2006;295(6):629-642