Study: Can population-based DNA sequencing find more people at risk for hereditary cancers?
|At a glance||Questions for your doctor|
This study is about:
Whether population-based screening for BRCA1 and BRCA2 mutations may identify substantially more patients who are at high risk for hereditary cancers than the current practice of using personal and family cancer history alone.
Why is this study important?
Identifying more patients who carry mutations in BRCA1 or BRCA2 provides an opportunity for improved cancer prevention, early detection, and access to new targeted therapies.
Adult participants were recruited from January 2014 to March 2016 through the Geisinger MvCode Community Health Initiative in Pennsylvania and New Jersey. Over 50,000 participants enrolled and consented to complete DNA sequencing of BRCA1 and BRCA2.
Of the 50,726 patients who underwent DNA sequencing, over 99% did not have a mutation. A BRCA1 or BRCA mutation was found in 0.5% (about 1 in 200) people tested.
Almost half of the 89 BRCA1 or BRCA2 mutation carriers who had not had prior testing and for whom comprehensive personal and family medical histories were available did not meet NCCN guidelines for clinical testing. These people would have been missed using standard recommendations for genetic counseling and testing.
These results are consistent with previous studies that showed that about 1 in 500 to 1 in 300 people in the general population will carry a BRCA1 or BRCA2 mutation. Like other studies, the results confirm that about half of all people with a BRCA1 or BRCA2 mutation do not have a strong family history of cancer.
What does this mean for me?
The National Comprehensive Cancer Network (NCCN) is a nonprofit network of leading cancer centers that publishes guidelines for genetic counseling and testing for BRCA. Current NCCN guidelines for mutations in BRCA1 and BRCA2 are based on personal and family history of cancer(s). However, these guidelines are not always applied correctly; nor do they always identify all BRCA mutation carriers.
The guidelines are based in part on having a noticeable family history of breast or ovarian cancer. These guidelines are likely to miss people with mutations:
- who come from small families
- when the BRCA mutation is inherited from the father's side of the family
- if there is lack of information (e.g. with adoptees)
This new research adds to other studies that have shown that current ways of identifying BRCA1 and BRCA2 mutation carriers are insufficient. Population-based genetic testing for inherited BRCA mutations may be a better way to identify high-risk patients and provide to them opportunities to reduce their risk of cancer. For more information on cancer risk management for mutation carriers click here.
At the 2018 Joining FORCEs Conference, renowned scientist Dr. Mary-Claire King, who discovered the BRCA1 gene, told attendees, “To identify a woman as a carrier only after she develops cancer is a failure of cancer prevention.” While Dr. King and others have been calling for population-based genetic testing for BRCA mutations, this is a bold challenge that demands careful consideration.
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Manickam K, Buchanan AH, Schwartz MLB, et al., "Exome Sequencing–Based Screening for BRCA1/2 Expected Pathogenic Variants Among Adult Biobank Participants." JAMA Netw Open. 2018. 1(5):e182140. King, M-C, Levy-Lahad E, and Lahad A. "Population-Based Screening for BRCA1 and BRCA2." JAMA. 2014. 312(11):1091-1092. Gabai-Kapara E, Lahad A, Kaufman B, et al. "Population-based screening for breast and ovarian cancer risk due to BRCA1 and BRCA2." Proc Natl Acad Sci U S A. 2014. 111(39):14205-10.
FORCE receives funding from industry sponsors, including companies that manufacture cancer drugs, tests and devices. All XRAYS articles are written independently of any sponsor and are reviewed by members of our Scientific Advisory Board prior to publication to assure scientific integrity.
This article is relevant for:
Women over age 30
This article is also relevant for:
Men with breast cancer
Breast cancer survivors
Women under 45
Women over 45
Healthy people with average cancer risk
Be part of XRAY:
NCCN guidelines recommend genetic counseling and testing for people without cancer who have the following family history:
- A relative who has tested positive for an inherited mutation in a gene that increases cancer risk.
- One or more first- or second-degree relatives with breast cancer and any of the following:
- diagnosed at age 45 or younger
- triple-negative breast cancer
- two separate breast cancers, with the first diagnosis at age 50 or younger
- male breast cancer
- One or more first- or second-degree relatives with:
- colorectal cancer before age 50
- endometrial cancer before age 50
- ovarian, fallopian tube, primary peritoneal cancer
- rare or childhood cancers
- One or more first-degree relatives with:
- metastatic or high-grade prostate cancer
- pancreatic cancer
- Two or more relatives on the same side of the family diagnosed with any combination of the following at any age:
- breast cancer
- pancreatic cancer
- prostate cancer
- adrenal cancer
- brain tumors
- endometrial cancer
- thyroid cancer
- kidney cancer
- diffuse gastric cancer
- colon cancer
- Do I meet criteria for genetic counseling and testing for BRCA1, BRCA2, or other high-risk cancer genes?
- If I do not meet criteria for genetic testing for high-risk cancer genes, what are the risks and benefits of genetic counseling and testing for me?
- Will my insurance pay for testing? If not, what are the costs for the test?
Below are clinical trials that include genetic counseling and testing.
- NCT02665195: Prospective Registry Of MultiPlex Testing (PROMPT). PROMPT is an online research registry. The goal of PROMPT is to help researchers to better understand the risks that are linked to mutations in less well-studied genes.
- NCT04245176: Genetic Testing for All Breast Cancer Patients (GET FACTS). This study looks at the impact of a novel genetic counseling method on surgical decisions in people with newly diagnosed breast cancer. This study involves genetic counseling about contralateral breast cancer risk.
- NCT02620852: WISDOM Study: Women Informed to Screen Depending on Measures of Risk offers women age 40-74 the opportunity to undergo risk assessment and genetic testing in order to determine the best breast screening options based on their situation.
- Enhancing Genetic Risk Assessment in Underserved Blacks and Latinas at Risk of Hereditary Breast Cancer. This study will test how well educational materials increase the use of knowledge about hereditary cancer risk.
- NCT04476654: Improving Uptake of Genetic Cancer Risk Assessment in African American Women-Video. This study looks at the usefulness of intervention with a culturally-tailored video to improve uptake of genetic counseling in Black women who are at increased risk of HBOC.
Other genetic counseling or testing studies may be found here.
Health care providers who are specially trained in genetics can help you more clearly understand your risk for hereditary cancer. The following resources can help you locate a genetics expert in your area.
- The National Society of Genetic Counselor website offers a searchable directory for finding a genetic counselor by state and specialty. To find a genetic counselor who specializes in cancer genetics, choose "cancer" under the options "Area of Practice/Specialization."
- InformedDNA is a network of board-certified genetic counselors providing this service by telephone. They can also help you find a qualified expert in your area for face-to-face genetic counseling if that is your preference.
- JScreen is a program from Emory University that provides low-cost genetic counseling and testing.
- Grey Genetics provides access to genetic counselors who offer genetic counseling by telephone.
- The Genetic Support Foundation offers genetic counseling with board-certified genetic counselors.
- FORCE's toll-free helpline at: 866-288-RISK, ext. 704 will connect you with a volunteer board-certified genetic counselor who can answer general questions about genetic testing and cancer and help you find a genetics expert near you.
- FORCE Peer Navigator Program will match you with a volunteer who has undergone genetic counseling and can help you navigate resources to find a genetic counselor near you.
- Ask your doctor for a referral to a genetics expert.
Who covered this study?
Yale Daily News
Most with cancer risk don’t know it, study finds This article rates 4.0 out of 5 stars
Genomic screening can ID undetected BRCA1/2 cancer risk This article rates 2.0 out of 5 stars
IN-DEPTH REVIEW OF RESEARCH
Clinical testing for BRCA mutations has been available for over 20 years. In the United States, between 1 in 300-500 are estimated to have an inherited BRCA mutation. This translates to between 250,000 and 415,000 women for whom breast and ovarian cancer is both highly likely and potentially preventable. However, the majority of these women do not know that they have a BRCA mutation.
The U.S. Preventative Services Task Force recommends testing only in at-risk populations. The guidelines are based in part on having a noticeable family history of breast or ovarian cancer. This is harder to observe when families are small or if the BRCA mutation is inherited from the father's side of the family or if there is lack of family medical information (e.g. with adoptees).
Some experts are concerned that guidelines are too narrow. A recent, eye-opening study out of Israel, for example, found that 50% of all women with a BRCA mutation had no history of breast or ovarian cancer. Some experts, including Dr. Mary-Claire King, now advocate voluntary genetic testing for all women after the age of 30.
Researchers of this study wanted to know:
Is population-based genetic testing a better way to identify BRCA mutation carriers than current practice?
This was a study of 50,726 adults who had exome sequencing from January 2014 to March 2016 as voluntary participants of the DiscovEHR cohort identified through the Giesinger MyCode Community Health Initiative in Pennsylvania. (Conducting sequencing on the portions of genes that encode proteins (exons) helps researchers to identify genetic mutations that influence disease.) Comparisons were made between clinical data from electronic health records and clinical visits.
Among the 50,726 patients who underwent sequencing:
- 50,459 (99.5% of patients tested) did not have a disease-causing mutation in BRCA1 or BRCA2.
- 267 (0.5% of patients tested) had inherited BRCA mutations.
- Among these patients:
- 219 (82.%) had no prior clinical testing
- 95 (35.6%) had a mutation in BRCA1; 172 (64.4%) had a mutation in BRCA2.
- 148 (55.4%) were women and 119 (44.6%) were men.
- Cancer was diagnosed in 56 (20.9%) of all 267 BRCA mutation carriers.
- Among these patients:
Twenty BRCA mutation carriers died before they received their results and 3 died after return of results (before June 30, 2017). Among the 23 deaths, the cause of death was determined to be a BRCA-associated cancer in 9 (39.1%) people. Cause of death was unrelated to BRCA in 11 (47.8%) and indeterminate in 3 (13%). Compared to deceased cases, 45 (18.4%) of living BRCA mutation carriers had a personal history of a BRCA-associated cancer.
Among the 148 women with BRCA mutations:
- 31 (20.9%) had a personal history of breast cancer as did 1,544 (5.2%) of 29,880 noncarriers.
- 15 (10.1%) had a personal history of ovarian cancer as did to 195 (0.6%) of 29,880 noncarriers.
BRCA1 or BRCA2 mutation carriers without prior testing but with comprehensive personal and family medical histories:
- 44 (49.4%) did not meet published guidelines for clinical testing.
Age was one limitation of this study. Participants were generally older than the health system’s patient population. More importantly, this study was skewed toward those patients who received regular health care, thereby increasing the opportunity to enroll in the biobank research. The higher incidence of breast cancer in the biobank population was also likely a reflection of age and frequency of care.
BRCA mutations predispose women to extremely high risks of breast and ovarian cancer, but these risks can be significantly lowered. For women with mutations in BRCA1 or BRCA2, surgical intervention, particularly risk-reducing salpingo-oophorectomy, reduces risk of both ovarian and breast cancer and reduces overall mortality. However, many women with mutations in these genes are identified as carriers only after their first cancer diagnosis because their family history of cancer was not sufficient to suggest genetic testing.
Although this study and others support genetic screening in healthy patients, we still do not have a perfect, all inclusive way to do that effectively. Minimally, patients must have good genetic counseling about the potential benefits and drawbacks of genetic testing.