Challenging the status quo
About 12 in 100 women will develop breast cancer at some point in their life, and one or two of these cases will be linked to an heritable gene mutation.1 These hereditary cases are more likely to be in individuals of Ashkenazi Jewish background, as they have a higher rate of BRCA gene mutations (1 in 40) — the most common mutations associated with breast cancer — than the general population (1 in 300 to 800).
A recent study by Cuiro and colleagues (2020)2, published in Clinical Breast Cancer, suggests that there is another ethnic group with a similar prevalence of genetic risk for breast cancer. The analysis of 761 individuals suggests that black individuals are as likely as the Ashkenazi Jewish population to have mutations in the BRCA1 and BRCA2 genes. These new findings warrant a reexamination of current hereditary cancer screening guidelines, offering insight into the barriers that black individuals encounter in understanding their cancer risk.
Ethnicity matters for genetic testing
Testing for heritable cancer mutations (e.g., BRCA1/2 mutations) informs providers about an individual’s risk of hereditary cancers. For example, patients with a mutation in BRCA1 or BRCA2 have a ~70% chance of developing breast cancer in their lifetime.3 For patients with significant family cancer history or with a hereditary cancer mutation, medical recommendations suggest that these individuals should have additional screenings (like breast MRI) to diagnose breast cancer early, when the tumor is most likely to respond to treatment. Insurance coverage for genetic testing often follows these recommendations. Genetic screening results can also provide information about how to best manage hereditary cancers.
Genetic testing for BRCA1/2 mutations is recommended for patients with strong family history of breast cancer per the National Comprehensive Cancer Network.4 The NCCN guidelines also state that BRCA1/2 testing can be considered for unaffected Ashkenazi Jewish patients, even without personal or family history of breast cancer. This guidance underscores the relevance of ethnicity when determining an individual’s hereditary cancer risk.
To better understand hereditary cancer risk in other ethnic cohorts, Cuiro and colleagues (2020) analyzed data collected in a Michigan hospital from 2008 to 2018. The analysis revealed a higher-than-expected BRCA prevalence in black individuals at 8.1%. In fact, the prevalence of these mutations in black individuals was substantially higher than non-Ashkenazi Jewish whites (3.6%), and it almost reached the riskof Ashkenazi Jewish individuals (9.3%). The overall prevalence in the high-risk cohort (5%) matches previously reported estimates. To be clear, these numbers reflect BRCA1/2 mutational frequencies in patients who were tested (i.e., high-risk patients), which is why they are at a much higher than they would be by estimates in the general population.
Genetic testing beyond guidelines
Cuiro and colleagues (2020) also investigated the reasons why the 329 patients that were excluded from the study did not complete testing. Overall, patients were excluded for a number of reasons, including not meeting NCCN guidelines for testing, insufficient insurance, and loss of follow-up. According to Cuiro and colleagues (2020), insufficient insurance and loss of follow-up to the clinic prevented 29.3% of black individuals from completing testing. Comparatively, only 8.5% of non-Ashkenazi Jewish whites failed to complete testing for the same reasons. These disparities highlight the barriers black individuals face when trying to access hereditary cancer screening.
Cuiro and colleagues (2020) argue that current hereditary screening guidelines should be revised to enable broader access to hereditary cancer screening among black individuals.
Many patients fall outside of medical guidelines and insurance coverage policies, but they could still benefit from hereditary cancer testing. Through our personalized cost estimates, compassionate care options, and family testing program, Natera is committed to providing access to high-quality, affordable genetic testing for all patients.
- Breast Cancer Risk and Risk Factors. June 2016. https://www.breastcancer.org/symptoms/understand_bc/risk
- Ciuro J, Beyer A, Fritzler J, Jackson N, Ahsan S. Health Care Disparities and Demand for Expanding Hereditary Breast Cancer Screening Guidelines in African Americans. Clinical Breast Cancer. 2020 Sept, in press.
- U.S. Breast Cancer Statistics. Feb 2021. https://www.breastcancer.org/symptoms/understand_bc/statistics
- NCCN Guidelines Insights: Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic, Version 1.2020. https://jnccn.org/view/journals/jnccn/18/4/article-p380.xml