If you’ve been following our blog or participating in our courses, you’ll know that there are many hereditary cancer syndromes that increase adults’ lifetime cancer risks. Often, adults undergoing genetic testing are motivated by obtaining risk information for their children. But, after receiving news of a pathogenic variant (mutation) in a cancer predisposition gene, many parents hesitate to tell their children. When should the kids find out, and in what situations should they be tested?
Discussing results with children is an ongoing conversation
Receiving news that you carry a pathogenic variant that increases cancer risk can be disconcerting, even someone motivated to be proactive. In addition to providing medical management advice, clinicians should also ensure patients are receiving the necessary emotional support from professionals and organizations that have experience working with patients with hereditary cancer risk.
This may be especially important for parents. Parents will benefit from support, not only to process their own reaction to a positive result, but also in discussing results with family and anticipating their reactions. For hereditary cancer syndromes with adult-onset risks, waiting to discuss their results may work out, in theory. After all, most guidelines recommend deferring genetic testing unless it would have direct impact on the child’s medical management. But we know that kids overhear adult conversations all the time. If a child inadvertently learns of their risk, they may wonder why the adults didn't discuss this with them. Will they develop misconceptions, such as overestimating their risk, or become overly worried or anxious?
Admittedly, disclosure of genetic results to children can be difficult for parents while they are going through their own adjustment to their carrier status or possibly their own active cancer treatment. Disclosure, however, can help kids assimilate risk knowledge into their self-identity, better plan for future health choices, and will often strengthen family relationships. Ideally, this will be an ongoing conversation, tailored to the child’s age and developmental stage.
In some cases, there may be a medical necessity for discussing results and arranging testing for children.
Exceptions to waiting until adulthood to test
Guidelines recommend deferring genetic testing for adult-onset conditions until adulthood in most instances. This is to preserve the child’s future autonomy in medical decision-making. There are exceptions, such as the American Academy of Pediatrics’ qualification that the waiting itself should not cause an undue psychological burden for the child. Another exception to waiting is when there may be risks of developing cancer in childhood.
First, pathogenic variants in some genes typically considered to be adult-onset may actually have childhood-onset risks. For example, consider the APC gene, associated with Familial Adenomatous Polyposis Syndrome (FAP) and colorectal cancer. If a pathogenic variant in the APC gene is detected, children in the family can be at risk of certain cancers if they also carry the variant. There is a risk of hepatoblastoma in young children ages 5 and younger. For older kids, colon cancer screening may begin as early as age 10 and thyroid cancer screening in the late teens. Li Fraumeni syndrome (TP53 gene) is another example of a cancer predisposition syndrome with cancer risks for children. Among these: leukemia, sarcoma and more.
Then, there may be rare cases where an adult-only onset syndrome was identified and family members were affected at very early ages. Predictive testing for relatives may be considered 10 years prior to the earliest diagnosis in the family. For example, if a BRCA carrier is diagnosed with breast cancer in her 20s, the usual recommendation for her daughter to wait until age 18 for genetic testing would not apply. Due to the potentially young age of cancer onset, predictive genetic testing should be considered. This can help inform early screening decisions if she tests positive for the familial variant.
Lastly, a broad multigene panel ordered for an adult patient may incidentally identify a childhood-onset syndrome. To learn more about hereditary pediatric cancer syndromes, check out the resources provided below.
Testing to inform reproductive considerations
What if a BRCA2 carrier has a partner who also carries a BRCA2 pathogenic variant? If their child inherits both pathogenic variants, a 1 in 4 chance, he or she will have a condition called Fanconi anemia. Fanconi anemia is a bone marrow failure syndrome with risks including growth deficiency, anemia, leukemia, and structural abnormalities of the skeletal system, heart, and kidney. Other genes also confer risk for children if both parents are carriers and both pass along the variants. These include other genes involved in Fanconi anemia, constitutional mismatch repair deficiency (Lynch syndrome genes), ataxia telangiectasia (ATM gene), fumarase deficiency (FH gene), among others. These syndromes are very rare, but clinicians should counsel individuals of reproductive age about these possibilities.
Patients interested in family planning may ask if they can do anything to prevent passing on risk to their children. They may wish to take advantage of preimplantation genetic diagnosis (PGD). PGD is a procedure in which a few cells are removed from an embryo, tested for the pathogenic variant, and unaffected embryos are selected for in-vitro fertilization (IVF).
Care coordination between cancer and prenatal genetic specialists can ensure appropriate and timely pretest counseling and testing for partners.
Hereditary cancer risk information is inherently familial in nature. Parents state they desire genetic testing not only to guide their own management but also to help their children. Sometimes this means test results will impact their children when they are young. Providers can help their patients frame information about childhood cancer risks for their kids in a constructive way. Families, however, adapt and communicate about cancer risk information in different ways, and the information to share can be complex. Genetic counselors remain an excellent resource for your patients to navigate this challenging territory.
Accessing Genetic Services (JAX). Lists tools and websites to help find genetic professionals and provides patient talking points about referring to genetics.
Cancer Genetic Clinical Education (JAX). Practice applying genetic information to realistic cases and learn about the value of genetic assessment and genetic testing to patient care. Earn free CME and CNE credit for each of eleven 15-minutes modules.
- Ataxia telangiectasia
- Constitutional mismatch repair deficiency and Lynch syndrome
- Fanconi anemia
- Fumarase deficiency
- Hereditary breast and ovarian cancer syndrome (BRCA1 and BRCA2)
- Li Fraumeni syndrome
- Familial adenomatous polyposis syndrome (FAP)
American Academy of Pediatrics and the American College of Medical Genetics and Genomics (2013).
Ethical and Policy Issues in Genetic Testing and Screening of Children.
Plon, SE and Malkin, D (2016). Childhood Cancer and Heredity. In P. A. Pizzo & D. G. Poplack (Eds.), Principles and Practice of Pediatric Oncology.
Scollon, S et al. (2017). A Comprehensive Review of Pediatric Tumors and Associated Cancer Predisposition Syndromes.
Werner-Lin, A, et al. (2018). Talking with Children About Adult-Onset Hereditary Cancer Risk: A Developmental Approach for Parents.