Genetic Testing for Breast Cancer: Who Should Get Tested?
Focused on Health - October 2008
By Rachel WintersGenes are what determine if our eyes are green or blue, and whether our hair is auburn or blonde. While genes establish the traits that make us each unique, genetic information can be altered or damaged. When this happens, cancer may develop. These altered or damaged genes can be passed down from generation to generation.
Joanne Beethe, 50, has two daughters and seven grandchildren ranging in age from two months to 10 years. She is extremely close to her family. Joanne, who everyone calls Joan, is an accountant, a self-starter and a breast cancer survivor.
After her diagnosis, Joan discovered that her cancer was most likely inherited. She was diagnosed with Hereditary Breast and Ovarian Cancer (HBOC) syndrome, which is a result of a mutation of the BRCA1 and/or BRCA2 genes.
“Knowing earlier that I had HBOC would’ve helped me,” said Joan. “I would have gotten more frequent mammograms, and I feel that my cancer could’ve been caught before it spread to my lymph nodes.”
Joan’s introduction to cancer began in May 2005 when her older brother died suddenly of cancer of an unknown origin. The following year, Joan’s father died, and the chaotic nature of her life caused her to miss her annual mammogram. It wasn’t until January, while dressing for work one morning, that Joan found a lump in her right breast. A few weeks later, she was dealt a hard blow – she was diagnosed with cancer in both breasts.
Joan’s breast cancer was triple-negative. A patient who has triple-negative breast cancer is estrogen receptor negative, progesterone receptor negative and HER2/NEU negative, so they can be more difficult to treat because they don’t respond to certain hormone or drug treatments. Triple negative breast cancers also can be more aggressive and are more likely to recur than other types of breast cancer.
“Before my brother died, I hadn’t given cancer much thought,” said Joan. “I always just had my mammograms. It’s ironic that I missed my annual mammogram the year following my brother’s death.”
It was the rare nature of her diagnosis that led Joan and her doctors to pursue genetic counseling and testing. Even though only five to 10% of breast cancers are inherited, understanding the hereditary component to breast cancer is key.
“It’s important that people know about HBOC,” said Joan. “There is power in knowledge. People who haven’t been tested don’t have the privilege of knowing, which is something that can help your family for generations.”
After completing her cancer family tree, Joan learned that she had always been at increased risk for developing breast cancer. She had an extensive family history which included a first cousin on her father’s side, her maternal grandfather, and a case of recurrent breast cancer in her mother’s sister who was diagnosed when she was 41-years-old
Once someone is told about a specific genetic mutation, doctors may recommend that they begin cancer screening at a younger age than what is usually advised for the general population. Screening enables health care providers to detect cancers as early as possible, when there is the best chance of successful treatment and cure.
Another option for women diagnosed with HBOC is preventive surgery or drug therapy.
“Preventive surgery can reduce breast and ovarian cancer risk by up to 95 percent, while drug treatment can reduce risks by up to 50 percent,” said Banu Arun, M.D., associate professor and clinical medical director of Cancer Genetics at M. D. Anderson.
Because of her HBOC diagnosis, Joan’s decision to have a double mastectomy was a lot easier to make. Now, after having undergone chemotherapy for six months, followed by six weeks of daily radiation and subsequent breast reconstruction surgery, Joan is almost fully recovered. She works with a personal trainer to manage her weight and remain healthy, and is back working full-time.
“I feel like a much stronger person now, having beaten breast cancer,” said Joan.
Since her mastectomy, Joan has chosen, with serious thought and support from her genetic counselors and physicians, to also have her ovaries removed as a preventive measure to developing ovarian cancer. In addition, Joan’s family made the difficult decision to undergo genetic testing themselves based on what they learned about HBOC.
“It is certainly a delicate matter, but I wanted my family members to be tested,” said Joan. “If you have HBOC, you have access to a world of treatment opportunities, and getting tested keeps me from having to worry.“
Both of Joan’s daughters, who each had a 50 percent chance of inheriting the BRCA mutation from Joan, tested negative for HBOC. Joan’s mother tested positive, and now gets breast MRIs in addition to her annual mammograms. She also is currently considering removing her ovaries as a preventive measure. Joan’s aunt recently had her ovaries removed, and will make sure that all of Joan’s cousins are tested – now, and far into the future.
Genetic testing isn’t for everyone. It involves many ethical, legal, and social issues that require careful consideration. There is currently legislation on the state and national level, in addition to the Genetic Information Nondiscrimination Act (GINA) that will be enacted in May 2009, to protect individuals in group health plans from discrimination based on genetic testing results. Just like all health information, genetic testing results are confidential, but genetic discrimination is still a topic to consider.
In addition, your genetic counselor or physician can try to help coordinate an insurance preauthorization so that genetic testing is a covered benefit, but some insurance companies will not pay for genetic testing and paying for it out of pocket can be expensive.
Individuals considering genetic testing should think about how it could cause changes in family relationships. Some family members may wish to be tested and know the results; others may prefer not to participate at all. These are all issues that should be discussed with a genetic counselor or physician.
“Genetic counseling and testing is a very personal decision, and individuals need to want to know this information, and then be ready to do something about it,” said Arun. “It’s not something to be taken lightly.”
How would I know if my family has a hereditary cancer?
In general, families at risk for an inherited form of cancer have family members who were diagnosed with:
- cancer at an early age
- the same or similar cancers
- cancer in more than one site in the body
- a rare cancer, such as male breast cancer
If you think your family is at risk for an inherited form of cancer, speak to your health care provider about your concerns. Obtaining detailed cancer histories for both sides of your family can play an important role in risk assessment.
“The most important thing is to identify first and second degree relatives who have had breast cancers in the family, and to know the ages they were diagnosed,” said Arun.
Estimated cancer risks associated with BRCA1 and BRCA2 mutations:
- Lifetime risk of breast cancer: 50-87%
- Lifetime risk of a second primary breast cancer: 40-60%
- Lifetime risk of ovarian cancer 15-44%
- Lifetime risk of breast cancer: Up to 6%
- Lifetime risk of prostate cancer: Up to 20%
Should I undergo genetic testing for breast cancer?
You and your family members should consider genetic counseling and testing if:
- You had breast cancer before age 50.
- You had breast and ovarian cancer.
- You had breast or ovarian cancer, and have relatives with breast or ovarian cancer.
- Any men in your family had breast cancer.
- You are of Ashkenazi (Eastern European) Jewish ancestry.
- A family member has already had genetic testing and has a BRCA1 or BRCA2 mutation.
Genetic testing may be used to help identify people who are at high risk for developing certain types of cancer before any symptoms appear.
“It is knowledge you want,” said Arun. “If you have a mutation you have up to an 80 percent chance of developing breast cancer and up to a 50 percent chance of developing ovarian cancer.”
What happens next?
For individuals with HBOC, breast cancer screening exams are recommended beginning at age 20 and include semi-annual or annual clinical breast exams and, beginning between ages 25 to 35, semi-annual or annual mammograms with alternating breast MRIs.
Although preventive screening for ovarian cancer has not been perfected and cannot detect all ovarian tumors, experts still recommend the following semi-annual tests for women with HBOC syndrome, beginning at age 25 to 35:
- Pelvic exam
- CA-125 blood test
- Transvaginal ultrasound
Where can I get genetic counseling or testing?
To make an appointment with a genetic counselor, contact M. D. Anderson’s Clinical Cancer Genetics Program at 713-745-7391.