The World Cancer Research Fund (2019) estimates that there were over 18 million cases of cancer in 2018. Most people are affected by cancer in one form or another and I am no exception - cancer seems to run in my family. My mother passed away from breast cancer in 2008 and my father passed away from pancreatic cancer in 2011. My maternal aunt also passed away from breast cancer and my maternal great grandmother survived breast cancer, living to the age of 92. Given this strong family history, I met with an oncologist and genetic counselor to assess my risk. My mother had been tested for the breast cancer genes, BRCA1 and BRCA2, both of which were negative. Based on this information, the genetic counselor felt I didn’t need additional genetic testing at the time and concluded that I am at a 30% higher risk of developing breast cancer during my lifetime compared to the general population. They recommended aggressive screening with annual mammograms alternating every six months with annual breast magnetic resonance imaging (MRI) in order to detect cancer early.
Approximately five to 10% of all cancers are caused by a genetic mutation (McReynolds & Lewis, 2017). Gene mutations can be inherited or acquired. An inherited gene mutation is present in the cells (egg or sperm) during conception and can be passed on to the next generation (American Cancer Society, 2019). An acquired (somatic) mutation does not come from a parent, rather it develops some time later in life due to environmental or lifestyle factors. “Family cancer syndromes” are caused by inherited mutations in tumor suppressor genes that usually control cells by slowing growth or division, repairing DNA mistakes, or causing cell death at the appropriate time (American Cancer Society, 2019). A few examples of family cancer syndromes include hereditary breast and ovarian cancer (HBOC) syndrome, Lynch syndrome (hereditary non-polyposis colorectal cancer) and Li-Fraumeni syndrome (sarcoma, leukemia, brain, adrenal cortex and breast cancer).
What is genetic testing and counseling?
Genetic testing uses medical test on tissue samples such as blood, hair, cheek cells, urine, or amniotic fluid to look for mutations in a person’s genes. Genetic counseling is the “process of helping people understand and adapt to the medical, psychological, and familial implications of genetic contributions to disease” (National Society of Genetic Counselors [NSGC], 2019). Genetic risk assessment and counseling should occur before genetic testing and often includes:
- Obtaining a detailed patient medical history and three- to four-generation family history of cancer (age, age at death, cancer type and age at diagnosis) as well as risk-reducing surgeries.
- Discussing testing options for genes - several genes can account for clustering of cancer in a family. Talk about how the results could impact medical management.
- Educating the patient on the genetics of cancer – all first-degree relatives of a carrier have a 50% chance of inheriting the same mutation.
- Providing information on testing, management, prevention, resources, and research
- Counseling to help make informed decisions
Who should be tested?
Patients should be referred to a genetic specialist for one or more of the following (American Cancer Society, 2019):
- Several first-degree relatives (mother, father, sisters, brothers, children) with cancer
- Many relatives on one side of the family who have had the same type of cancer
- A cluster of cancers in your family that are known to be linked to a single gene mutation (breast, ovarian and pancreatic cancer)
- Family member with more than one type of cancer
- Family members who had cancer at a younger age than typical for that type of cancer
- Close relatives with cancers that are linked to rare heredity cancer syndromes
- Family member with a rare cancer (i.e. retinoblastoma)
- Ethnicity (i.e. Jewish heritage is linked to ovarian and breast cancers)
- Physical finding linked to an inherited cancer (i.e. having several colon polyps)
- Known genetic mutation in one or more family members who have had genetic testing
Genetic testing results can be very confusing. The results can be positive, negative, true negative, or a variant of uncertain significance (VUS). Let’s explore what these terms mean (McReynolds & Lewis, 2017):
- Positive –A genetic mutation was found and the patient is at increased risk of cancer. This result may help determine risk reduction options such as increased screenings or risk-reducing surgery.
- Negative –There was no mutation in the genes tested, however there may be a mutation in a different gene that was not tested, or a mutation was not detectable in the genes that were tested with the current technology. Cancer risk and screening is based on the patient’s history and family history.
- True Negative – The patient tested negative for a known mutation that was found in a family member. Risk for cancer development is not zero.
- Variant of Uncertain Significance – A change in the DNA was detected and may or may not affect the function of the gene. The patient does not have an increased risk for developing cancer, but the risk is also not zero. This result should not be used to make decisions about medical management.
What role do nurses play in genetic counseling and testing?
Genetic counseling should be performed by providers who have had proper education and training, and have obtained a master’s degree and certification from the American Board of Genetic Counseling. The American Nurses Association (ANA) in collaboration with the International Society of Nurses in Genetics (ISONG) established core competencies for nurses who provide genetic counseling and the American Nurses Credentialing Center now offers board certification in Advanced Genetics Nursing (AGN-BC) for master’s-prepared nurses who specialize in genetics. In addition, the ANA, ISONG, and the National Coalition for Health Professional Education in Genetics have established the “Essential Genetic and Genomic Competencies for Nurses with Graduate Degrees.” It outlines the various ways nurse practitioners (NPs) can support patients through the genetic testing process, including (McReynolds & Lewis, 2017):
- Identifying patients for referral
- Preparing patients by explaining the benefits, risks, and limitations of testing
- Managing care following results and ordering cancer screenings as needed to reduce risk
- Providing emotional support
Genetics is an evolving field that impacts most medical conditions today. New innovations in screening and testing continue to be made and new cancer-causing genes are being discovered. Nurses play an important role in providing information and education to their patients. Possessing a fundamental understanding of these complex and confusing concepts provides nurses with the skills necessary to support their patients.
American Cancer Society. (2019). What is genetic testing? Retrieved from https://www.cancer.org/cancer/cancer-causes/genetics/understanding-genetic-testing-for-cancer.html
McReynolds, K. & Lewis, S. (2017). Genetic counseling for hereditary cancer: A primer for NPs. The Nurse Practitioner, 42 (7), 22-28.
National Comprehensive Cancer Network. (2016). Genetic/familial high-risk assessment: breast and ovarian. Version 2.2017. Retrieved from http://www.nccn.org.
National Society of Genetic Counselors. (2019). Retrieved from http://www.nsgc.org.
World Cancer Research Fund. (2019). Worldwide cancer data: Global cancer statistics for the most common cancers. Retrieved from https://www.wcrf.org/dietandcancer/cancer-trends/worldwide-cancer-data
More Reading and Resources
Cancer Genetics Fundamentals
Nurse Faculty Knowledge of and Confidence in Teaching Genetics/Genomics: Implications for Faculty Development
The Complexities of Cancer Risk Evaluation
The Cancer Worry Scale Revised for Breast Cancer Genetic Counseling