A Tough Decision
Though heart disease is the number one cause of death for women, the greatest fear for many is breast cancer. A woman who has a family history of breast cancer feels especially vulnerable and wonders, “Did I inherit breast cancer? Do I have a genetic flaw?”
“All cancer is genetic,” says Dr. Edward Dalton, medical director of the Elliott Breast Health Center in Manchester. “In any cancer, certain genes are not performing in the normal way. A gene has been damaged. As cells reproduce, the damaged or mutated gene is replicated. At some point, there are enough copies of the damaged gene to produce cancer. But this is not the same as ‘inherited.’”
Only 7 to 10 percent of all breast cancers are the result of inheriting an abnormal gene. Two such genes — BRCA1 and BRCA2 — have been identified.
Ann Jeffers-Brown is a genetics counselor at the Elliot Breast Health Center. The center is one of two programs in the state that can provide genetic testing for breast cancer patients: the other is the Norris Cotton Cancer Center at Dartmouth-Hitchcock Medical Center, a National Cancer Institute-designated comprehensive cancer center.
Jeffers-Brown counsels individuals and families about the option of genetic testing to determine the presence of BRCA1 or BRCA2. “I’m a genetics geek,” she says with a laugh. But she is serious about the importance of this work. She is there to help women understand their risk of cancer and evaluate their options. Her clients have a diagnosis of breast or ovarian cancer, or family histories that indicate substantial risk.
The first step in the process is to gather the family history, through four generations if possible. Important considerations include the number of first-degree relatives (parents, siblings) who have had cancer, the number of second-degree relatives (aunts, grandparents), their ages at diagnosis and the outcomes.
“We are just beginning to be able to look at genomic patterns,” she says. “Genes have been identified in certain families, in which there is a clear pattern of breast and/or ovarian cancer. These damaged or mutated genes are passed from one generation to the next by female or male relatives.” Inheriting the gene does not mean that one has cancer, but the risk is substantially higher.
The lifetime risk of cancer from random genetic damage or copying errors in cell division is about 12 percent. These damaged cells often self-destruct and the healthy cells are sufficient to carry on the work of regulating cell division. For a woman who has BRCA1 or BRCA2, the lifetime risk of cancer is 82-85 percent. Every cell in the breast carries one copy of the damaged gene. The random damage that occurs throughout life, added to existing cancer cells, is much more likely to result in cancer for these women.
Certain patterns are indicators that BRCA1 or BRCA2 may be present. Early onset of cancer is one warning sign. A majority of breast cancers develop after menopause; the statistical risk of cancer increases as a woman ages. But cancer that results from the inherited gene usually develops before menopause. Bi-lateral breast cancer and ovarian cancer are also indicators that BRCA1 or BRCA2 may be present.
Jeffers-Brown uses a computer software program that gives a risk assessment, based on the family history and personal data obtained from the patient. Using that number, plus her personal assessment, she decides whether to pursue the issue of genetic testing.
The decision to be tested, or not, is complex and emotional. One woman may decide, “I want to know. Then I can get on with my life, whatever it brings.” Another may say, “What would I do with this knowledge? I would rather not know.” Yet another wonders if she should tell her sisters or cousins, who may also be at risk. The choice is painful. Feelings of guilt, anger and sorrow may be present in two or three generations. Jeffers-Brown says that her role in helping people sort through these questions is as important as understanding the genetics.
If a woman opts for testing and finds that she does carry either of the two genes, what then? Until recently her choices were to “wait and hope” or to have a prophylactic mastectomy, the removal of both breasts. Some women choose the mastectomy. It is a drastic step but the risk of cancer is reduced by 90 percent.
Other women are reluctant to take that step. They choose to follow an increased surveillance and prevention program. Surveillance will include a mammogram every six months, a breast MRI every six months and a minimum of two clinical breast exams each year. A patient may also take tamoxifen. Jeffers-Brown explains that using tamoxifen as part of a prevention program has been studied for 10 years and “the results are good.”
The use of MRI as a screening and a diagnostic tool is a recent development. An MRI can identify a cancer at an earlier stage. It is particularly helpful for a woman with unusually dense breast tissue. It seems logical that the use of MRI will improve results. Dr. Dalton is optimistic, but he cautions that it is too soon to know how that translates into long-term survival. The technique is expensive and for most women not necessary.
A woman who has inherited the mutated gene also has a greater risk of ovarian cancer. Jeffers-Brown anticipates the development of a blood test to identify the risk of ovarian cancer, but that is several years away. As yet, there is no reliable screening for ovarian cancer. Most are not detected till the cancer has progressed to late stage. Therefore, it is usually recommended that a woman who carries a gene for cancer have her ovaries removed after she is finished with childbearing. “Inheriting a mutation in BRCA1 or BRCA2 does not affect a young woman’s fertility, nor should it interrupt her plans for a family,” Jeffers-Brown says.
Factors that have reduced a woman’s exposure to estrogen reduce her risk of both breast and ovarian cancer somewhat. This would include having children early and breast-feeding. Taking oral contraceptives for three years reduces the risk for ovarian cancer by about 60 percent, but may slightly increase the risk for breast cancer.
There are other variables in determining a woman’s risk for cancer. Some factors, including the number of pregnancies, impact carriers of BRCA 1 and BRCA 2 in different ways. Others, such as late onset of menstruation, lower the risk of breast cancer for both. The impact of toxic environmental exposure is not fully understood. Likewise, the role of diet in cancer prevention needs more study.
“Our knowledge is expanding,” says Jeffers-Brown. “We are just beginning to look at genomic patterns. Someday, not too far down the road, we will be able to provide a genetic risk assessment for all women.” There is research going on now to develop a test to assess patterns in multiple genes that fit together. With that information, surveillance and treatment can be tailored to the specific risk of each woman. NH