Families with Breast Cancer

Medical Author: Carolyn Janet Crandall, MD, FACP
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

Ms. G. is a 40-year-old woman with two small children. Like most women, she is concerned about her chances of developing breast cancer. She asks her doctor about her risks. Although breast cancer is a worry for most women, Ms. G. is especially worried because of a family history of breast cancer. Her mother and sister had breast cancers that were diagnosed at young ages.

A woman with a family history of breast cancer has a lot of concerns. Among other things, she is thinking of her job, children, and husband, as well as how her medical insurance and health team will be able to serve her needs in the future should a crisis arise.

What are the facts about families that have multiple members with breast cancer?

Inherited breast cancer disorders account for a small minority of breast cancers overall. Genes are the "messages" in each cell of the body that determine the ultimate design of our bodies. Genes can be damaged by the environment. Additionally, people can be born with defects in the genes that remove the body's defenses against cancers. Only in about 10% of all breast cancer cases is there actually a genetic defect that can be tested. This means that 90% of breast cancers are due to other causes. In fact, most cases of breast cancer occur in women who do not have a family history of breast cancer. A complex interplay between environmental and genetic factors affect the development of breast cancer, and all the key factors have not yet been identified.

How does Ms. G. decide if she should have genetic testing?

The whole issue of genetic testing for breast cancer is complicated. Recent research indicates that the information women seek most often when they request genetic testing does not match what they can realistically determine from this testing. Nevertheless, it is worthwhile to consider the role of this testing and what it involves.

Certain characteristics make a woman at higher risk for rare, genetic breast cancer disorders. These factors include (1) family members with breast cancer, especially at a young age, (2) breast cancer in a male family member, (3) both breast and ovarian cancer in the family, (4) cases of bilateral breast cancer in a single family member, (5) cases of breast cancer diagnosed at very young ages, and (6) being of Ashkenazi Jewish descent. Ms. G. and her doctor determine that she falls within the higher risk factors because her sister and mother both had breast cancer at young ages.

Women at risk for a genetic breast cancer disorder must understand what the genetic testing process involves.

First, an expert reviews the family medical history to evaluate what sort of pattern of genetic breast cancer may be occurring. Next, the family member's tumor sample undergoes testing. It is impossible to run tests to analyze every single gene in a woman. Therefore, the nature of the specific disorder is narrowed by testing of the specific tumor from an affected family member. The tests are designed to determine if any of the known genetic breast cancers has caused the tumor to grow. If the defect is found on the tissue sample of the woman's relative, the lab will then know exactly which defect needs testing in the blood sample of the woman herself. In this way, a woman will be able to be counseled about her own risk. Counseling, education, and emotional support are expected both before and after any testing, no matter what the result.

Prior to undergoing testing, it is essential that women consider the benefits and risks in light of the possible results. For example, if her test is positive (meaning she is affected by a genetic disorder) there are measures that can reduce her breast cancer risk. One of these is having breast tissue surgically removed. This is an unpleasant prospect for many women. Removal of the ovaries also appears to be helpful in reducing risk. There are no medications specifically approved for use in reducing the risk in women with genetic breast cancer disorders, although tamoxifen and other medications are actively being studied.

While Ms. G. is considering these surgery options, she must also decide a variety of issues such as (1) whom she would tell, (2) whether her own children should be tested, and (3) how her health insurance and/or job will be affected. If she does not desire to inform anyone about a positive test and would not consider having surgery, then perhaps she may not want to be tested in the first place. On the other hand, what if the test results for Ms. G. are negative? This may be a relief. However, there is also the frustrating fact that even if a woman has a negative genetic test, she is still at higher risk for breast cancer than the general population due to the risk factor of having multiple family members with breast cancer.

What about the many women who do not fit the pattern of a genetic breast cancer disorder? How worried should they be?

Although most women who are surveyed think breast cancer is the leading cause of death in women, heart disease is actually the leading cause of death in women. Heart disease kills one out of two women, far in excess of the number of deaths caused by breast cancer. It is important to keep the perspective that most women who have only one family member with breast cancer should be more concerned with discussing heart disease prevention with their physicians than breast cancer prevention.

Summary

In conclusion, any woman in Ms. G.'s situation needs to talk to a doctor who is specially educated to counsel high-risk women regarding if and when they should be tested and how to act on the different test result scenarios--all prior to testing. There is further counseling after testing, whether results are positive or negative. Research is progressing rapidly, with the results of new studies coming out all the time.