Hereditary Breast and Ovarian Cancer. Identifying Your Risk.

Each year, more than 200,000 women in the U.S. learn they have breast cancer, and over 20,000 find out they have ovarian cancer. While most of these cancers happen by chance, 5 to 10 percent of breast and about 15 percent of ovarian cancers are linked to an inherited gene mutation.

During a free health lecture held on Oct. 15 at the Boulder Jewish Community Center, oncologist David Andorsky, MD, and genetic counselor Breanna Roscow, MS, CGC – both with Rocky Mountain Cancer Centers – explained the link between genetics and breast and ovarian cancers, as well as how genetic testing could help determine whether you’re at risk. Read what they had to say.

How Can Cancer be Inherited?

“Hereditary breast and ovarian cancers are caused by abnormal genes passed from parent to child—from either the mother’s or father’s side,” Dr. Andorsky told lecture attendees.

He described how genes are made up of DNA, which contain instructions for regulating cell growth. Damage or changes in the DNA can produce the wrong set of instructions, altering normal cell production.

“DNA can become damaged or changed as a result of natural aging processes, environmental and lifestyle factors or an inherited genetic mutation,” Dr. Andorsky said. “Some DNA changes are harmless, but others can give rise to cancer by allowing cells to grow and divide in an uncontrolled way, forming a tumor.”

BRCA1 and BRCA2 Genes

Inherited breast and ovarian cancers are often associated with genetic mutations in two genes: BRCA1 and BRCA2 (BReast CAncer genes 1 and 2).

“Despite what their names suggest, these genes don’t cause cancer. Instead, they normally play a role in protecting you from cancer by repairing damaged DNA and keeping breast, ovarian and other cells from growing uncontrollably,” said Dr. Andorsky.

Because of this, the BRCA genes are actually known as tumor-suppressing genes.

“However, in some people these tumor-suppressing genes don’t function properly because they contain hereditary mutations passed down from parent to child. This can, in turn, lead to the development of cancer, especially breast and ovarian cancer,” he explained.

Dr. Andorsky described how every individual has two copies of BRCA1 and BRCA2 genes. One copy is inherited from your mother, and the other from your father. Yet it takes only one defective copy to increase your cancer risk significantly.

“Though some patients with BRCA1 or BRCA2 mutations never develop cancer, because there is random chance involved in which DNA errors occur,” he added.

BRCA Mutations and Ashkenazi Jewish Heritage

BRCA1 and BRCA2 gene mutations are found in people of all ethnic and racial backgrounds. However, certain groups are more likely to carry an altered BRCA1 or BRCA2 gene.

“For example, there are three specific BRCA1 or BRCA2 gene mutations, called founder mutations, seen with increased frequency in Ashkenazi Jewish or Eastern European ancestry. In fact, about 1 in 40 Ashkenazi Jews have a BRCA1 or BRCA2 gene mutation, compared to 1 in 300 to 500 individuals in the general U.S. population,” Dr. Andorsky stated.

Getting Tested for a Genetic Mutation

Roscow followed Dr. Andorsky with an explanation of how effective medical options are now available for individuals more likely to get hereditary breast and ovarian cancers. She said learning about your hereditary risk can go a long way in helping you take the right steps to prevent the cancers.

“A genetic counselor can help you assess your cancer risks and answer any questions you may have,” said Roscow. “Your counselor can also help determine whether you and your family are likely to have a mutation that make it worth getting tested.”

Roscow stated that genetic testing involves a blood or saliva test performed by a specialized laboratory. According to the Centers for Disease Control and Prevention (CDC), testing is usually recommended when you have any of the following:

• A known BRCA1, BRACA2 or other inherited mutation in your family.
• A strong family health history of breast and ovarian cancer, early onset cancers or multiple cancers in a single person.
• A moderate family health history of breast and ovarian cancer and are of Ashkenazi Jewish or Eastern European descent.
• A personal history of female breast cancer that meets certain criteria such as age at diagnosis, type of cancer and family health history.
• A personal history of ovarian, fallopian tube or primary peritoneal cancer, male breast cancer, pancreatic cancer or aggressive prostate cancer.

“Women with a family history of breast or ovarian cancer can benefit from broader, multigene panel tests, which look for mutations in several genes at the same time, including BRCA1 and BRCA2. Therefore, we usually recommend panel testing for anybody who qualifies for genetic testing,” Roscow said.

“However, genetic testing is not always needed. We can still use family history or personal history to estimate your risk using various risk assessment models,” Roscow clarified.

How Much Does Having a BRCA1 or BRCA2 Gene Mutation Increase Your Risk?

Women with a BRCA1 or BRCA2 mutation face a dramatically increased lifetime risk of breast cancer: 72 percent of women who inherit a BRCA1 mutation and about 69 percent of women who inherit a BRCA2 mutation are likely to develop breast cancer by the age of 80, compared with about 12 percent for women with no inherited genetic risk.

Roscow explained, “While most of the cancers associated with mutations in these genes only occur in women, men with hereditary breast or ovarian cancer can also be at increased risk of developing certain cancers, like prostate cancer. For this reason, we also encourage men who have a family history of cancer to talk with a genetic counselor.”

Ovarian cancer risk with a BRCA1 or BRCA2 mutation is much higher, too – 44 percent of women who inherit a BRCA1 mutation and about 17 percent of women who inherit a BRCA2 mutation will likely develop ovarian cancer by the age of 80, compared to about 1.3 percent of women in the general population without the mutation.

While the risks of cancer are significantly higher for men and women who have a BRCA1 or BRCA2 mutation, increased screening and preventative surgical options have been shown to dramatically reduce the risk of cancer or identify cancer early, when it is most easily treated and cured.

To make an appointment with oncologist David Andorsky, MD, call Rocky Mountain Cancer Centers at (303) 385-2000. To make an appointment with genetic counselor Breanna Roscow, MS, CGC, call 303-930-7872.

View their PowerPoint slides from the free health lecture on “Identifying Your Risk for Hereditary Breast and Ovarian Cancer.”

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