By Will Boggs MD
NEW YORK (Reuters Health) - 20/8/2019
In an updated recommendation, the US Preventive Services Task Force (USPSTF) is expanding the population eligible for BRCA screening.
The USPSTF now says risk assessment for BRCA-related cancer may be appropriate for women with a personal or family history of breast, ovarian, tubal, or peritoneal cancer or women who have an ancestry associated with BRCA1/2 gene mutations. Women with a positive result on the risk assessment tool should receive genetic counseling and, if indicated, genetic testing.
Routine assessment in other asymptomatic women is not recommended, according to the USPSTF.
"Whether or not the harms of risk assessment, counseling, testing, and interventions outweigh the benefits depends on a woman's individual risk profile and family history," Dr. Douglas K. Owens, Task Force member from Stanford University, Stanford, California, told Reuters Health by email. "That is why it is important for women who are concerned about their risk of having a BRCA mutation to discuss benefits and harms with their doctor."
"Each step in the process can be complex, and sometimes it makes sense for a woman to only get an assessment and undergo counseling, but not genetic testing," he said. "It is also important to note that test results are complex and can't always definitively tell a woman if she has a potentially harmful mutation that will lead to cancer."
Potentially harmful mutations of the BRCA1/2 genes, which occur in an estimated 1 in 300 to 500 women, are associated with an increased risk for breast, ovarian, fallopian tube, and peritoneal cancer and account for 5% to 10% of breast cancer cases and 15% of ovarian cancer cases.
The USPSTF previously established that there is adequate evidence that current genetic tests can accurately detect known BRCA1/2 mutations, but who should undergo such testing remains controversial.
Dr. Owens and colleagues reviewed existing evidence in order to update USPSTF recommendations on risk assessment, genetic counseling, and genetic testing for BRCA-related cancer in women who are asymptomatic for BRCA-related cancer and have unknown BRCA mutation status. This includes women who have never been diagnosed with BRCA-related cancer and those with a previous breast, ovarian, tubal, or peritoneal cancer diagnosis who have completed treatment and are considered cancer-free but have not been previously tested.
In this population, USPSTF recommends that primary care clinicians assess women with a personal or family history of breast, ovarian, tubal, or peritoneal cancer or who have an ancestry associated with BRCA1/2 gene mutations (for example, Ashkenazi Jewish ancestry) using an appropriate brief familial risk assessment tool.
Reasonable assessment tools include the Ontario Family History Assessment Tool, Manchester Scoring System, Referral Screening Tool, Pedigree Assessment Tool, 7-Question Family History Screening Tool, International Breast Cancer Intervention Study Instrument (Tyrer-Cuzick), and brief versions of BRCAPRO.
Women with positive results on one of these assessment tools should receive genetic counseling, which should include detailed kindred analysis and risk assessment for potentially harmful BRCA1/2 mutations, identification of candidates for testing, patient education, and discussion of the benefits and harms of genetic testing.
Genetic testing should only be undertaken in women with a personal or family history that suggests an inherited cancer susceptibility who are willing to see a health professional who is suitably trained to provide genetic counseling and interpret test results, and only when test results will aid in decision-making.
Women found to have harmful BRCA1/2 mutations can be managed with a variety of interventions to lower their future cancer risk, including intensive screening, risk-reducing medications, and risk-reducing mastectomy and salpingo-oophorectomy.
"The most important thing to remember is that there are several steps women can take to determine if they're potentially at increased risk for BRCA gene mutations - and if genetic counseling and BRCA testing are needed," Dr. Owens said.
Dr. Heidi D. Nelson from Pacific Northwest Evidence-based Practice Center, Oregon Health and Science University, Portland, who co-authored the evidence report on which the USPSTF recommendation statement is based, told Reuters Health by email, "The process of familial risk assessment in primary care, referral and evaluation by genetic counselors, genetic testing, and use of intensive screening and risk-reducing medications and surgical procedures is complex. Each step of the pathway requires careful interpretation of information, consideration of future risks, and shared decision-making before moving on to the next step."
The review identified no studies that evaluated the effectiveness of risk assessment, genetic counseling, and genetic testing in reducing the incidence and mortality of BRCA1/2-related cancer.
"More information is needed about mutation prevalence and the effect of testing in the general population, including whether testing actually results in lower cancer mortality," she said. "Current research focuses on highly selected women in referral centers and may not be relevant to others."
"Presence of a pathogenic BRCA1/2 mutation indicates higher risk of cancer, not that it will necessarily occur," Dr. Nelson said. "Interpretation of this risk is more meaningful for women with family histories of BRCA1/2-related cancer. Genetic testing in women without family cancer histories may provide inaccurate risk estimates and lead to inappropriate decisions to reduce risk, such as excessive imaging or bilateral mastectomy and salpingo-oophorectomy."
Dr. Susan Domchek from Basser Center for BRCA, University of Pennsylvania, Philadelphia, who co-authored an editorial related to these reports, told Reuters Health by email, "There are two important changes in the current recommendation: inclusion of women with prior breast or ovarian cancer who are considered cancer free, and the second to explicitly include ancestry as a risk factor. Neither of these two changes is particularly controversial."
"Many individuals at high risk of having a BRCA1/2 mutation are not tested," she said. "Oncologists, primary care doctors, gynecologists, other health care providers, and patients should all be aware of the options for genetic testing. At the same time, we should all strive to reduce barriers and ensure equitable access to genetic testing."
Dr. Larissa A. Korde from National Cancer Institute, Rockville, Maryland, who co-authored another editorial related to these reports, told Reuters Health, "The field of cancer genetics is rapidly evolving, For example, there is currently not much information available on the risks and benefits associated with screening for BRCA mutations in men, although men also face significant cancer risk if they carry a mutation."
"I also think it is important to highlight the increasing availability of direct-to-consumer (DTC) testing for hereditary cancer syndromes," she said. "Some DTC tests are very comprehensive, and others are not; some have associated genetic counseling available, while others don't. Again, while the panel did not address this, it is something that both physicians and patients need to be aware of."
"I think awareness of a cancer family history is the key for both patients and physicians," Dr. Korde said. "Knowing which cancers are associated with BRCA mutation, in both men and women, will lead to the successful identification of those who should be tested."
Dr. Lisa Newman from New York-Presbyterian/Weill Cornell Medical Center, New York wrote a third editorial related to these reports. She told Reuters Health by email, "Physicians and the general population must be mindful of all cancer-associated risk factors, which include family history, lifestyle, and ancestral background. Knowledge of these risk factors can influence screening recommendations as well as other healthcare options such as genetic testing and chemoprevention."
"Population-based data regarding the cancer burden of other population subsets suggests that we should broaden our criteria for defining high-risk ancestral groups," she said. "For example, African American women have a twofold higher risk of triple negative breast cancer (TNBC) compared to White Americans, and TNBC is a marker of hereditary breast cancer susceptibility. Available studies on genetic testing in African American families, however, are limited, and so the USPSTF recommendation does not specify African ancestry as a background warranting heightened concern for genetic cancer predisposition. Paradoxically, adherence to the USPSTF recommendation for genetic counseling referrals could increase the existing disparity in genetic testing information among African ancestry families."
The complete USPSTF recommendation statement, evidence review, and related editorials were published online August 20 in JAMA.
Stay up-to-date with Medicom. Subscribe to the Medicom Conference Reports and newsletter.
Medicom provides the highest quality medical information and tools to international medical professionals.