A patient’s guide to understanding hereditary cancer genetic testing

The last week of September marks the beginning of National Hereditary Cancer week, a time to bring awareness to hereditary cancers and provide education about the genetic conditions that cause them.

Cancer itself cannot be inherited from parent to child; however, having a parent with cancer may increase your risk. Cancer can be categorized as hereditary, sporadic, or familial. 

Hereditary Cancer

Hereditary cancer is when there is a single inherited genetic change responsible for the cancer within a family. Individuals with this inherited genetic change are born with a significantly increased risk of cancer compared to the general population. Ovarian, pancreatic, medullary thyroid cancers, and pheochromocytoma are more likely to be hereditary.

Sporadic Cancer

Sporadic cancer is a cancer that happens by chance from DNA changes which are the direct result of environmental changes, such as aging, smoking, and continuous exposure to carcinogens. Lung, papillary thyroid, and cervical cancers are more likely to be sporadic.

Familial Cancer

Familial cancer is when there is a clustering of cancer within a family that may be caused by multiple genetic and environmental factors. Examples of shared environmental risks include diet, where you live, smoking, and general lifestyle. Breast, prostate, and colon cancers are more likely to be familial. 

There are many reasons why you may want to consider genetic testing for inherited cancer predisposition syndromes. However, not everyone is a good candidate for genetic testing. In general, you may have a higher-than-average risk of hereditary cancer if you have:

• Cancer diagnosed at an early age (under 50)
  
• Cancer in 2 or more closely related relatives (on the same side of the family)
  
• Multiple generations in the family with cancer
  
• Multiple primary tumors in the same person 

Guidelines created through the National Comprehensive Cancer Network (NCCN) are available to assist in identifying who should consider testing.

If your personal or family history is suggestive of hereditary cancer, you should consider speaking with your provider about the implications of genetic testing. If you have concerns about risk of discrimination, federal law under the Genetic Information Nondiscrimination Act (GINA) provides some protection against certain, but not all, forms of discrimination. Consult with your provider to learn more about how these laws apply to you, as additional protections vary by state. 

To ensure you are receiving the most informative and helpful results from your genetic testing, you should:

• Consult with your healthcare provider, such as a genetic counselor, to review your family history and determine which test is best for you. 
  
• Your healthcare provider will place the order for your genetic testing.
  
• Your DNA is collected through blood, saliva, buccal (cheek) swab or skin biopsy.
  
• Results are released to your ordering healthcare provider and reviewed with you.

After getting genetic testing for hereditary cancer, there are 3 main types of results you may receive: 

• Positive – A result of positive, pathogenic or likely-pathogenic indicates you carry a genetic change that puts you at a higher-than-average risk of developing specific types of cancer. 
  
• Negative – A negative result indicates no genetic changes that increase the risk for cancer were found in the genes tested. A negative test can mean different things depending on the individual’s personal and family history of cancer and whether there is a known pathogenic (cancer-causing) variant in the family. A genetic counselor or other healthcare provider can help to determine the most appropriate next steps, which may include additional genetic testing.
  
• Variant(s) of unknown clinical significance (VUS) – A result of VUS indicates a change in the gene was found but, at this time, there is not enough information to know whether this genetic change causes an increased risk for cancer or not. 
  

If you have questions about your results after speaking to your healthcare provider, consider reaching out to the performing laboratory. At Quest Diagnostics, genomic science specialists (often known as genetic counselors) are available to review your results with you. These Quest specialists can be reached by calling 1.866.GENE.INFO (1.866.436.3463).

A positive result for a hereditary cancer gene indicates an increased risk of developing cancer. It does not indicate that you have or will have a diagnosis of cancer. Most of the time, a positive result indicates a diagnosis of hereditary cancer syndrome. These syndromes can explain some patterns of cancer seen within families. It’s important to share these results with your family members since they may want to consider genetic testing to assess their risk.

The most common examples of hereditary cancer syndromes are Lynch syndrome and hereditary breast and ovarian cancer syndrome. Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer, increases the risk of developing colorectal, endometrial, ovarian and many other types of cancer often before the age of 50. Hereditary breast and ovarian cancer syndrome, also called HBOC syndrome, increases the risk of breast, ovarian, pancreatic, and prostate cancer, as well as melanoma (a kind of skin cancer).

The information a positive result provides can aid in making informed medical decisions. There are options available for cancer prevention and early detection once an inherited risk is discovered. These medical management options may include increased screenings (in frequency and beginning at a younger age), cancer preventing surgeries and/or personalized treatment of cancer if present. Guidelines are constantly evolving and can be utilized in the decision-making process for medical management. However, these are not specific to any one individual. Each individual’s gender, age, medical history, family history, quality of life goals, reproductive desires, general health status, and other medical information should be considered when developing a medical management plan. 

• Learn more about Hereditary Cancer at Hereditary cancer | Quest Diagnostics
  
• Speak with a Quest specialist at 1.866.GENEINF0 (1.866.436.3463) about which tests may be best for you, and what your results mean.
  
• National Society of Genetic Counselors Home (nsgc.org) 
  
• Facing Our Risk of Cancer Empowered (FORCE) FORCE - Facing Hereditary Cancer Empowered home page (facingourrisk.org)
  
• More information regarding financial support for patients can be found at: Financial support for patients | Quest Diagnostics
  
• Additional information about GINA https://www.genome.gov/about-genomics/policy-issues/Genetic-Discrimination
  

FORCE (Facing Hereditary Cancer Empowered). Inherited Mutations and Cancer. Updated January 31, 2022. Accessed September 4, 2024. https://www.facingourrisk.org/info/hereditary-cancer-and-genetic-testing/hereditary-cancer/inherited-mutations-and-cancer

Garutti M, Foffano L, Mazzeo R, et al. Hereditary Cancer Syndromes: A Comprehensive Review with a Visual Tool. Genes (Basel). 2023;14(5):1025. Published 2023 Apr 30. doi:10.3390/genes14051025

Imyanitov EN, Kuligina ES, Sokolenko AP, et al. Hereditary cancer syndromes. World J Clin Oncol. 2023;14(2):40-68. doi:10.5306/wjco.v14.i2.40

LaDuca, H., Polley, E.C., Yussuf, A. et al. A clinical guide to hereditary cancer panel testing: evaluation of gene-specific cancer associations and sensitivity of genetic testing criteria in a cohort of 165,000 high-risk patients. Genet Med 22, 407–415 (2020). https://doi.org/10.1038/s41436-019-0633-8 

National Cancer Institute. Genetic Testing for Inherited Cancer Risk. Reviewed April 18, 2024. Accessed September 4, 2024. https://www.cancer.gov/about-cancer/causes-prevention/genetics/genetic-testing-fact-sheet

National Cancer Institute. The Genetics of Cancer. Updated August 8, 2024. Accessed September 4, 2024. https://www.cancer.gov/about-cancer/causes-prevention/genetics

National Comprehensive Cancer Network®. NCCN Clinical Practice Guidelines in Oncology. Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic. V3.2024. http://www.NCCN.org

National Comprehensive Cancer Network®. NCCN Clinical Practice Guidelines in Oncology. Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, and Gastric. V1.2024. http://www.NCCN.org