Direct-to-Consumer Genomic Testing in Patients With Cancer
Direct-to-consumer genomic testing (DTCGT) is a patient-initiated type of testing that is marketed to the general public in advertisements on all media. The tests can be purchased online or in stores without requiring a healthcare professional order or third-party payer authorization. Customers send a saliva sample to the company and view their test results on a secure website, but the results are not included in their electronic health record unless they specifically request it.
Types of Testing
Consumers can choose from several types or combinations (https://doi.org/10.1016/j.mayocp.2017.11.001) of DTCGT:
- Disease-risk tests estimate their chance of developing common diseases caused by both environmental factors and multiple variants in several genes (e.g., Alzheimer disease, heart disease) or carrier status for less common diseases (e.g., cystic fibrosis, sickle cell disease).
- Ancestry tests provide clues about a person's heritage or ethnicity.
- Kinship testing identifies biologic relations (e.g., paternity testing).
- Lifestyle testing claims to provide information about nutrition, fitness, weight loss, skincare, sleep, and food preferences based on variations in DNA. Lifestyle DTCGT companies may also sell services or products related to the test results.
Cautions for Consumers
DTCGT does not necessarily sequence an entire gene; when it sequences only a subset of variants, it may miss disease-causing variants (https://doi.org/10.1002/jgc4.1310). For example, 23andMe analyzes (https://medical.23andme.com/23andmes-new-brca1-brca2-report/) for the 185delAG and 5382insC variants in the BRCA1 gene and the 6174delT variant in the BRCA2 gene, but it does not provide information on other pathogenic variants in BRCA1 or BRCA2 or many of the other genes associated with germline risk for developing malignancy.
Upon request, most DTCGT companies will provide consumers with their sample’s raw data (https://doi.org/10.1136/bmj.l5688) that include extensive unanalyzed information, with the caveat that the raw data are only for research purposes and not for diagnostic purposes. Consumers may buy services from other online companies to analyze and interpret the raw data, but regulation is scarce.
The genomic data from a DTCGT is considered personal health information. DTCGT laboratories are responsible for (https://doi.org/10.5858/arpa.2020-0078-RA) managing the sample, safeguarding the data, and controlling whether and how the data will be used for secondary purposes (e.g., research, advertising).
Risks and Benefits
Marketing for DTCGT promotes awareness of genomics’ role in disease (https://doi.org/10.1016/j.mayocp.2017.11.001) and may encourage individuals to be proactive about their health, particularly with following prevention and healthy behavior (https://doi.org/10.1016/j.mayocp.2017.11.001) recommendations.
However, because of its potential to miss pathogenic variants, DTCGT may put consumers at risk for making life-altering decisions about prevention or screening based on inaccurate, incomplete, or misunderstood information (https://doi.org/10.1002/jgc4.1310). If a DTCGT identifies a pathogenic variant, it should be confirmed in a Clinical Laboratory Improvement Amendments of 1988–certified laboratory (https://doi.org/10.7326/m18-2356), which may be associated with additional costs.
DTCGT is typically completed without pretest counseling, which may restrict true informed consent and leave consumers unprepared for the implications of a test result or that the results may lack clinical utility. Lack of pretest assessment and counseling with a genetics professional increases consumers’ risk of obtaining the wrong test (https://doi.org/10.1097/PPO.0000000000000391) or a test from a laboratory with questionable quality.
Unexpected results about health, family relationships, or ancestry may have psychosocial implications (https://doi.org/10.1016/j.mayocp.2017.11.001), and although the Genetic Information Nondiscrimination Act (https://www.govinfo.gov/content/pkg/PLAW-110publ233/pdf/PLAW-110publ233.pdf) provides protections for health insurance and employment, DTCGT may affect an individual’s ability to obtain (https://doi.org/10.1188/20.CJON.135-137) life, disability, or long-term care insurance, contributing to financial distress.
Implications for Nurses
Patients may ask their oncology nurses about their DTCGT results, the data analysis in a DTCGT report or a third-party interpretation, or clinical biomarker testing and DTCGT in general. Referral to a genetic professional (https://doi.org/10.1002/jgc4.1310) is often indicated. As patient educators, oncology nurses must take every opportunity to explain the differences between diagnostic tests and DTCGT, the importance of personal and medical family history in genomic testing, and how testing influences recommendations for care.