Huge Underuse of Genetic Testing Among Cancer Survivors  

Kristin Jenkins

August 24, 2017

Fewer than 1 in 5 survivors of breast and ovarian cancers have undergone genetic testing for heritable mutations affecting genes such as BRCA1 and BRCA2, which means that more than a million women in the United States are not receiving recommended care.

The finding, reported in a study published online August 18 in the Journal of Clinical Oncology, highlights a huge underuse of genetic testing, say the reserachers.

"Large national efforts are warranted to address this unmet need," they write.

"Many of these women have inherited genetic changes that put them and their family members at risk for future cancers," lead author, Christopher P. Childers, MD, from the Department of Surgery at David Geffen School of Medicine at the University of California, Los Angeles, said in a statment.

"Identifying a mutation is often important for surgical decision-making and cancer therapy, but its importance extends further than that," he continued. "If individuals are aware that they have these mutations, they can take steps to lower their future cancer risk."

In an accompanying accompanying editorial, Kevin S. Hughes, MD, from Massachusetts General Hospital and Harvard Medical School, Boston, warns that these new findings represent just the tip of the iceberg.

Dr Hughes points to evidence from another recent study of patterns in genetic testing for breast and ovarian cancer risk in the United States showing that 90% of unaffected BRCA carriers — or an estimated 10.7 million women— also need to be tested.

It's time to increase the detection rate of preventable cancer by moving genetic testing from a "cottage industry" to population-level screening, Dr Hughes emphasizes.

"Our problem, which desperately cries out for a solution, is that huge numbers of high-risk patients who could be identified by genetic testing are instead developing cancer and often dying of that disease," he writes.

It will soon become impossible to practice medicine without genetics. Dr Kevin S. Hughes

Clinicians have to get directly involved in genetic counseling and testing, perhaps with the help of directed education and software that support clinical decision-making, Dr Hughes says. "The corpus of genetic information is extensive and growing exponentially. Is it realistic to expect all physicians to be facile with genetics? The answer is, they will have to be. It will soon become impossible to practice medicine without genetics."

The finding comes from an analysis of data from the 2005, 2010, and 2015 National Health Interview Surveys, which show that 1.2 million to 1.3 million women (or fewer than 1 in 5) did not have a simple blood or saliva test even though they met select National Comprehensive Cancer Network (NCCN) screening criteria for lowering future cancer risk, according to Childers and colleagues.

Most of these women — including 70% of 800,000 eligible patients with breast cancer and 80% of 400,000 eligible patients with ovarian cancer — never discussed genetic testing with a healthcare provider, the researchers note.  

Of 47,218 women identified in the study, 2.7% had a history of breast cancer and 0.4% had history of ovarian cancer. In those with breast cancer, 35.6% met one or more select eligibility criteria. Of this group, 29.0% discussed testing with a healthcare provider, 20.2% were advised to undergo testing, and 15.3% actually underwent genetic testing.

In women age 45 years and younger, testing rates for individual eligibility criteria ranged from 6.2% to 18.2%. Among those with ovarian cancer, testing was discussed with 15.1%, while 13.1% were advised to undergo testing and 10.5% actually got tested.

Ovarian cancer seems to be a particularly unrecognized indication for genetic testing. Childers et al.

"Although rates of testing are low across the entire study, ovarian cancer seems to be a particularly unrecognized indication for genetic testing," the study authors point out. "NCCN guidelines have recommended genetic testing for patients with a history of ovarian cancer since at least 2010. Previous studies have shown this discrepancy, but the magnitude of this deficit was not previously known."

Just the Tip of the Iceberg

A recent study of directed education showed that with just 6 hours of training, primary care physicians could effectively manage pretest counseling, provide results, and arrange management for whole-genome sequencing. Even patient satisfaction was good. "This suggests that, with a few hours of training, physicians could learn to give informed consent, order appropriate testing, interpret results, and arrange management (when obvious) or know when to refer (when not obvious) for cancer genetic testing," writes Dr Hughes.

Population-level screening may also need to be extended beyond the research setting, he says, pointing to evidence that women can be safely recruited for BRCA testing through newspapers or magazines with little or no pretest counseling.

"Barriers of Care"

Understanding the number of steps a patient has to take to navigate genetic testing may also provide some insight into "the barriers of care," the study authors say. Of every 100 eligible patients, for example, their study showed there was no discussion of testing with 75. Another 7 patients didn't return after discussion of testing, and 4 patients who were advised to get tested didn't get the test.

The gaps between discussing and advising may reflect a lack of provider awareness and knowledge about how to identify patients eligible for testing, they say, noting "the rapid evolution of NCCN guidelines."

Most primary care providers appear to be aware of BRCA mutations, but a 2011 study confirmed that only 20% could accurately identify NCCN guidelines, the study authors point out. "When women change doctors, their new physicians may not be aware of their histories or of the new eligibility guidelines," senior study author, James Macinko, PhD, professor of health policy and management at the UCLA Fielding School of Public Health, Los Angeles, California, said in a statement.

Five NCCN criteria were used to identify women who should get genetic testing. In addition to all women with a personal or family history of ovarian cancer, testing is recommended in women with breast cancer who are diagnosed at age 45 years or younger, or who are diagnosed at age 50 years or earlier and also have a mother, sister, or daughter with breast cancer. It is also recommended in women who have a mother, sister, or daughter diagnosed with breast cancer at age 50 or younger.

Improved Support Systems for Providers

Approached for comment, Graham A. Colditz, MD, DrPH, associate director of prevention and control at Siteman Cancer Center and Washington University School of Medicine in St Louis, Missouri, said that improved support systems for providers to interpret results of genetic testing and guide patients to counseling and prevention could speed up implementation of routine genetic screening practice for all patients with breast and ovarian cancer.

"A panel test administered to women at the time of diagnosis can inform their treatment and also help identify predisposing genetic markers that have implications for family members," said Dr Colditz, who was not affiliated with the study. "With appropriate communication and support for family members, those who carry the high-risk genetic markers can be identified and offered appropriate prevention strategies."

In Ohio, for example, this approach is being used in Lynch syndrome, with state-wide testing for colon cancer patients with identification of high-risk family members and referral for colonoscopy or other prevention strategies. In addition, the National Cancer Institute Cancer Moonshot program aims to accelerate cancer research into prevention, early detection, and treatment while placing an emphasis on achieving benefit equitably across the whole population. Wider implementation of Lynch syndrome testing is also a recommended Moonshot research priority, Dr Colditz noted.

However, Dr Colditz told Medscape Medical News, unless all women have health insurance, "we are not positioned as a nation to implement a true population-wide screening and prevention strategy." Programs such as the National Breast and Cervical Cancer Early Detection Program  provide greater access to Papanicolaou smears and mammography for many but not all low-income and uninsured women. Similarly, access to screening for colorectal cancer remains highly variable across the country and across racial and socioeconomic boundaries.

"If testing were adopted as a population-wide strategy, say at a woman's 30th birthday, then millions of women face catch-up to get the testing," Dr Colditz explained. "If only top-level healthcare insurance covered testing and the management of risk for those who are positive," he warned, "then rolling out widespread population level testing could exacerbate disparities in incidence and outcomes from these cancers for years to come."

For now, clinicians need a better infrastructure to communicate the risks and benefits of prevention strategies that vary by age. Better tools need to be developed so that clinicians can interpret and advise women based on genomic test results, with resources for family members who need to understand their own potential risk.

"The management plan for patients who test positive must be clear," Dr Colditz said, pointing out that testing without access to appropriate management doesn't constitute a true screening program. In fact, it may be considered unethical by World Health Organization standards for population-wide screening.

The Agency for Healthcare Research and Quality funded this study. Dr Childers and study coauthors have disclosed no relevant financial relationships. Dr Hughes reports stock or ownership of Hughes RiskApps, and CRA, as well as relationships with Myriad Genetics, Veritas Genetics, Focal Therapeutics, and Health Beacons. Dr Colditz has disclosed no relevant financial relationships.

J Clin Oncol. Published online August 18, 2017. Abstract, Editorial

Follow Medscape Oncology on Twitter: @MedscapeOnc

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