Genetic testing for breast, hereditary cancers is rapidly evolving science
30 to 40 genes currently associated with breast cancer
Only nine years ago, genetic testing for hereditary breast cancer risks focused on two well-known genes called BRCA1 and BRCA2.
Today, genetic testing for breast cancer can cover more than 30 genes, said Kim Kinnear, a genetic counselor who sees patients at UCHealth Jan Bishop Cancer Center in Steamboat Springs.
“I typically include 90 to 100 genes when I test people, including those 30 to 40 genes known to be associated with breast cancer,” Kinnear said.
The science of genetic testing to help determine the risk of inherited cancers or to help advise treatments after breast cancer diagnosis is a rapidly evolving and improving science.
Genetic testing can be performed for people 18 and older through UCHealth Yampa Valley Medical Center via an in-clinic blood draw or at home through a saliva collection kit, Kinnear said. Genetic testing costs $250 and is often covered by health insurance. The accompanying genetic counseling visits at UCHealth are free.
Dr. Jeff Chamberlain, an obstetrician-gynecologist with UCHealth Women’s Care Clinics in Steamboat Springs and Craig, calls genetic testing a very valuable, advanced tool that is fast, accessible, easy and reliable. The doctor said genetic testing is becoming increasingly sophisticated, and local doctors are pleased to have genetic counseling teams available for patients through UCHealth.
Genetic counselor Kim Kinnear, who sees patients at the UCHealth Jan Bishop Cancer Center in Steamboat Springs, provides guidelines for when genetic testing for breast cancer is recommended. In this case, “close family” means children, siblings, parents, grandparents, nieces/nephews and aunts/uncles.
Hereditary risk checklist:
If one or more of the following situations apply to you or your close family, you may want to meet with a genetic counselor:
• Many of your relatives had cancer
• Two or more of your relatives had the same type of cancer
• You and a relative had the same type of cancer
• You or a relative were diagnosed with cancer before age 50 or had more than one type of cancer
• You or a relative had a rare cancer (for example, breast cancer in a male)
• You or a relative had a cancer that is more likely to be inherited (ovarian, pancreatic, metastatic prostate)
Breast cancer specific checklist:
Who should consider genetic counseling and testing for breast cancer or other hereditary cancer genes:
• You had breast cancer (at any age)
• Close family member(s) had young breast cancer, meaning at age 45 or younger
• Three close family members on the same side of the family had breast or prostate cancer
• Close family member(s) had pancreatic, ovarian cancer or male breast cancer (with or without breast cancer in the family)
• You have Ashkenazi Jewish ancestry
• You have a known genetic finding in the family (for example, your cousin tested positive for BRCA1)
Chamberlain said genetic testing helps create a more comprehensive picture for patients with breast cancer risk factors, including a family history of hereditary cancer. Learning as much as possible about breast cancer risk and diagnosis are key because about 1 in 8 women in the U.S., or about 13%, will have breast cancer in their lifetime.
“About 43,600 women in the U.S. are expected to die in 2021 from breast cancer,” according to the nonprofit BreastCancer.org.
Chamberlain said patients should be as proactive and accurate as possible when providing their family history of cancer for their personal medical records as that information can raise a warning flag to indicate a need for genetic testing or for starting mammograms or other screenings earlier. The nonprofit Susan G. Komen organization also offers a “My Family Health History” tool online at Komen.org/fhht/index.html.
Patients with a family history of early cancers should start screenings 10 years before the earliest diagnosis age of a close family member with hereditary cancers, such as breast and colorectal, Kinnear said.
Genetic testing can be performed before or after a breast cancer diagnosis, said Kinnear, who earned a master’s degree in human genetics and genetic counseling from Stanford University School of Medicine. Genetic testing prior to diagnosis may be recommended based on family history and risk factors, and testing after a breast cancer diagnosis may help guide treatment and surgery decisions. Kinnear said all patients diagnosed with breast cancer who are younger than 65 are recommended for genetic testing to help guide possible surgical decisions and to inform family members of risks.
“Genetic testing is interesting when helping people to make decisions about their life and help reduce their long-term risk for breast cancer in context of their family history,” Chamberlain said.
Genetic testing looks for specific inherited mutations in a person’s genome that are harmful, which means they are known to increase the risks for diseases, such as specific cancers. While advances in genetic testing for breast cancer are positive and ongoing, Kinnear noted that currently only 5% to 10% of breast cancers are linked to a known genetic risk factor.
However, “we don’t know all of the genes that cause breast cancer yet,” Kinnear said.
The genetic counselor said many types of cancer can benefit from genetic testing but not cancers caused by nonhereditary issues, such as lung, esophageal, liver, cervical and anal cancers.
Kinnear said genetic testing can also impact nonsurgical treatment options since targeted therapies now exist for the most harmful genetic mutations.
For example, if someone inherits what we call a pathogenic variant, previously called a mutation, in a gene, including BRCA1 or BRCA2, there may be targeted treatments available to them. PARP (poly-ADP ribose polymerase) inhibitors are a new targeted treatment that can be used in the treatment of advanced breast, ovarian and other cancers for those with BRCA pathogenic variants,” Kinnear said, citing just one targeted treatment example.
The genetic counselor said the harmful BRCA1 or BRCA2 variants are found in 1 in 400 women in the general population and in 1 in 40 women of Ashkenazi Jewish heritage.
For genetic testing, patients first meet with a genetic counselor to review family history so the counselor can order the appropriate testing. Test results take two to three weeks usually through a lab in San Francisco, and results are always reviewed with a genetic counselor, she noted.
Kinnear said for patients with three or more cases of hereditary cancer on one side of the family, patients can start genetic testing after age 18. She recommends updated testing every five years since the science is progressing rapidly.
To reach Suzie Romig, call 970-871-4205 or email sromig@SteamboatPilot.com.
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This article is the second part of a two-part series. The first installment covered what insulin is and how it was discovered.