New research reveals that the current process of identifying people with BRCA gene mutations in the Jewish population — which relies on assessing someone’s family history — misses half the people who have the mutation and are at risk of developing cancer.
Women carrying a BRCA 1 or 2 gene mutation have a greatly increased risk of developing certain cancers. Approximately 15-45 percent of BRCA 1/2 mutation carriers will develop ovarian cancer and 45-65 percent will develop breast cancer by age 70, compared to 1.4 percent and 12 percent, respectively, in the general population. Women who know they are carriers can better manage their risk of developing cancer by enhanced screening or risk-reducing surgery.
Currently, testing for genetic mutations uses a family history-based approach whereby women are eligible for testing if they have a strong family history of BRCA 1/2 mutations and/or certain patterns of cancer diagnoses, such as breast cancer diagnosed at an usually early (e.g., before age 40 or 50). This is in contrast to population-based screening methods in which all members of a particular population group are universally screened.
In this latest study, researchers from the Genetic Cancer Prediction through Population Screening (GCaPPS) assessed the difference between family history-based testing and population screening in the Ashkenazi Jewish community, which is known to have a significantly higher number of people carrying the BRCA gene mutations than the non-Jewish population.
The researchers also carried out a cost-effectiveness analysis, and a study of the impact of testing on psychological health and quality of life, to address concerns that have been raised in the past when the issue of universal testing has come up. The results from both papers are published in the Journal of the National Cancer Institute.
Family history screening misses more than half of carriers
In the study, researchers found that 56 percent of people carrying a BRCA mutation were not identified by the existing family history criteria but were identified by population testing. Other key findings include:
- No significant difference in the short-term psychological impact or quality of life between those tested through population screening than those through family history testing.
- Screening all Ashkenazi Jewish women aged 30 and over, compared with family history testing, would cut the number of ovarian and breast cancers that occur and could potentially save millions in health care costs.
“Women at increased risk of cancer deserve far more than today’s genetic screening process gives them,” says Athena Lamnisos, CEO of the Eve Appeal, which funded the research. “This study shows that broadening genetic testing beyond just family history saves more lives and more money.”
Findings ‘raise the possibility of new approaches’ to genetic risk screening
These findings have very important implications, the researchers note. For the Ashkenazi Jewish community specifically, the results “suggest that population testing for BRCA1/2 mutations could save lives, is felt to be acceptable, and would be cost effective,” says lead investigator Dr. Ian Jacobs, Vice-President and Dean of the Faculty of Medical and Human Sciences at the University of Manchester.
Like other gene mutations, BRCA1/2 mutations are rare in the general population. In the U.S., between one in 400 and one in 800 people in the general population have a BRCA1/2 mutation. However, prevalence varies by ethnic group. Among Ashkenazi Jewish men and women, about one in 40 have a BRCA1/2 mutation. Although testing all members of the general population is impractical given the high cost of current testing methods and the low population-based prevalence of gene mutations, this study suggests that population-based screening methods may be suitable for certain high-risk subgroups.
“More broadly, [the findings] raise the possibility of new approaches to testing populations for cancer predisposing inherited genetic changes. As knowledge of the genetic basis of cancer increases, the acceptability to society of this type of testing rises and the cost of testing falls, we are likely to see rapid change in the way we deliver cancer genetic testing in health care,” adds Dr. Jacobs.
In their own words
Carolyn Graham, 42, took part in the GCaPPS study in 2011. She lost her mother to breast cancer but was unable to obtain genetic testing on the NHS. The study confirmed that she was carrying the BRCA2 gene mutation and she opted for surgical risk management. Carolyn underwent an oopherectomy (removal of both ovaries) followed by a double mastectomy and reconstruction in January 2012. She has recovered well from surgery and says that without GCaPPS’s testing program she would have felt like a walking time bomb.
Caroline Presho, 41, underwent a preventative double mastectomy when she was 36 years old after testing positive for a BRCA gene mutation three years earlier. Caroline’s family is of Ashkenazi Jewish descent but despite losing both her aunt and father to cancer she didn’t meet the family history criteria to have genetic testing.
“The current guidelines meant initially I wasn’t eligible for BRCA screening, even with my Ashkenazi Jewish ancestry,” says Presho. “Subsequent access to BRCA testing empowered me to make informed decisions about my personal health. This type of proactive healthcare not only saves lives, but will also save considerable amounts of money.”