What Genetics Means in Hereditary Cancer

Genetic Testing

Genetic testing options now include panels of tests, combined tumor and germline testing, and direct-to-consumer (DTC) testing. Oncology nurses must be knowledgeable and able to educate patients about those concepts as well as about how to access comprehensive genetic care.

The process begins with careful risk assessment and testing of the family member most likely to provide informative results. Following testing, expertise is needed to interpret the results and provide recommendations for care based on medical and family history as well as test results.

The possible results of genetic testing include a positive finding, a true negative finding, a noninformative negative, and a variant of unknown clinical significance. Although positive, negative, and noninformative negative results are actionable, a variant of unknown significance is not.

Genetic testing has implications for an entire family. Genetic risk assessment is an ongoing process because family cancer histories are dynamic and change over time. Recommendations for follow-up need to be updated as new information becomes available.

Providing comprehensive care not only for the patient but also for other family members is an often-overlooked area of genetics care, according to Mahon. Opportunities for the prevention and early detection of malignancy can be missed when care is not coordinated and all potentially at-risk individuals are not offered testing.

Over-the-Counter Tests

With the increasing availability and popularity of DTC genetic testing, oncology nurses have a progressively more important role in helping patients understand what the tests can do as well as their limitations. Although such testing may promote awareness of genetic diseases and allow consumers to take a more proactive role in their health care, it also poses a risk for misinterpretation of test results and concerns about privacy and confidentiality.

DTC genetic tests typically involve analyzing single nucleotide polymorphisms (SNPs), or single-letter variations in the genome. However, identified SNPs account for a minority of heritable cancer risk. Because the implications of risk predictions based on SNP profiles are unclear, no standard recommendations exist regarding medical management based on the results of such testing. 

The Importance of Counseling

Credentialed genetics professionals can provide assistance across the continuum of genetic testing and care, including with risk assessment, selecting the most appropriate testing strategy and laboratory, interpreting test results, making follow-up recommendations, identifying options for research studies, and coordinating appropriate care for the entire family.

Oncology nurses can work closely with genetics professionals by identifying potential families that should have a genetic evaluation, ensuring that recommendations for care are implemented, and providing psychosocial support as individuals and families cope with a diagnosis of a hereditary predisposition for developing cancer.

Ultimately, Mahon said, coordinated genetic care can reduce the morbidity and mortality associated with a hereditary predisposition for developing cancer.