Genetic testing for pediatric cancer

When is it appropriate for a child to have a genetic test? Counselors weigh in.

Genetic testing for pediatric cancer

Cancer can affect anyone — even kids. This is especially frightening for parents, who want to protect their children from pediatric cancer which can be a deadly disease.

Here, Sanford Health genetic counselors Lisa Ohden and Shelby Brown weigh in on the complex issue of running predisposition genetic tests on children.

Genetic testing isn’t a simple answer

As genetic counselors, families with a personal or family history of cancer ask to speak with us. In some cases, this leads to a discussion of whether genetic testing is appropriate for their children to see if they have a predisposition for hereditary cancers or conditions.

While this may sound like an easy answer to a difficult question, it’s quite the opposite.

Anytime you’re talking about predisposition testing, it gets to be a long, complicated conversation about a lot of ethical and emotional issues.

When you consider the fact that testing would be on someone who likely is too young to comprehend the effects of knowing these kinds of test results, it can turn into a dilemma for parents.

Why do you want to run a genetic test?

During a genetic counseling session, we may discuss the motivation for testing.

  • Was this strongly recommended by a provider?
  • Is it a primary concern for the parents due to general anxiety?
  • Is there guilt that something could or did happen?
  • Do they have a family history of cancer or a particular syndrome?
  • Is it because they want to make sure their child is getting the right screenings?

The majority of time, in our genetic counseling sessions, we’re not actually doing testing. We’re just talking.

We’re getting to the root of why parents may want the genetic testing done, explaining what that genetic testing can and can’t tell you, discussing when and why it would or wouldn’t be appropriate to test a child, and going through scenarios to make sure families understand the full implications that the results of a genetic test can have.

In many cases, we may come to a mutual decision that genetic testing is not appropriate at this time.

There’s no taking back the information

Genetic testing is a family decision. Even though you’re testing one individual, it impacts all the family members.

Once you know that information, there’s no taking it back. If you’re predisposed, it can deeply affect you and your family emotionally. It can affect lifestyle choices, decisions and even your identity. It could have implications for the rest of your life.

There can be a lot of psychosocial counseling with these discussions. Genetic testing isn’t like any other blood draw, however. It can have implications for more than one person’s lifetime.

Is it appropriate to test a child?

Another major subject we discuss is whether it’s appropriate to test a child for that particular condition.

While there are many ethical components to consider, autonomy of the child becomes a focal point of our discussion. Autonomy refers to the right for an individual to decide for themselves whether they want to pursue something like predictive genetic testing for cancer predisposition.

For example, if a mother has a BRCA1 gene variant that predisposes her to breast cancer, and she wants to know if her presently healthy child carries that same gene variant and predisposition, we generally would not recommend a child having that genetic testing.

The cancer risks associated with BRCA1 variants are essentially isolated to adults. There are no pediatric guidelines for patients, and there is no medical action to take at that age.

So we ask: What are you going to do with the test results now? What if your child regrets knowing this information as they get older and they would have chosen not to know? What if that knowledge affects the lifestyle and identity choices they make in their formative years?

When weighing cost vs. benefit, it is probably not appropriate to test a child for BRCA1 in most circumstances.

Hereditary conditions with pediatric screenings

There are, however, some conditions that we may recommend genetic testing for in children. A number of cancer predisposition syndromes have published management guidelines for children.

For example, say a parent is diagnosed with familial adenomatous polyposis (FAP) syndrome, a genetic condition that causes many polyps to form along the gastrointestinal tract. If left untreated, the risk for cancer is nearly 100 percent over that person’s lifetime.

FAP is inherited in an autosomal dominant pattern. When the parent is affected, there is a 50 percent chance for each of their children to inherit that condition. With FAP, children could be predisposed to early symptoms and cancers.

There are screening recommendations for children, even babies, with FAP. These can catch cancerous tumors or pre-cancerous polyps early and get them treatment sooner.

So in a case like this, where there is a strong hereditary link and established protocols for children, after talking with the parents and providers, we may recommend a child getting genetic testing.

Conditions that especially affect children

In addition to FAP, some other more common inherited conditions with pediatric cancer screening protocols include:

  • Li-Fraumeni syndrome
  • Gorlin syndrome
  • Hereditary retinoblastoma
  • Juvenile polyposis syndrome
  • Neurofibromatosis type 1
  • Cowden syndrome

Genetic testing occurs only after discussing family history and symptoms, and making sure everyone agrees that it is appropriate.

We want to know that the family understands what having a child with this condition means for them. We also want them to understand the child’s health care going forward.

A lot will change for the patient’s pediatric care. Additionally, later in life these conditions will affect both childhood and adult screenings.

With some of these conditions, there are certain cancers that appear primarily in pediatric cases. These include retinoblastoma, hepatoblastoma and optic glioma. In the grand scheme of things, though, pediatric cancers are very rare with hereditary cancer predisposition syndromes.

Pediatric cancer is rarely hereditary

Only about 10% of childhood cancer has a genetic link. The other 90% of the time, the cancer occurred by chance. This is because of an environmental exposure, or because of an unidentifiable predisposition in the family.

Parents of these children may ask to meet with us, even if it’s not suspected to be genetic. We answer their questions and provide perspective so the family can decide next steps.

In cases where parents are concerned about a family history of cancer, the most appropriate person to have genetic testing is the relative with cancer. If we can solve why that person developed their cancer, we may gain a better understanding of the child’s risk.

It is important to remember, however, that very few cancer predisposition syndromes are fully penetrant. This means that even if you test positive for a cancer gene variant, it’s not a guarantee you will develop cancer.

That test result may help us understand that you are more likely to develop cancer than your neighbor is. However, the benefit in knowing is the increased screenings your doctor will recommend.

No guarantees, but some peace of mind

Every parent wants reassurance their child won’t get pediatric cancer. In most cases, genetic testing can’t answer that question either.

Even if there’s a negative result in a genetic test, we can’t guarantee they won’t get cancer. That’s really hard for parents. There’s always the factors of environmental or spontaneous changes that may develop into cancer.

Genetic testing doesn’t always rule out or rule in a condition — it’s impossible to give exact zero or 100% answers. Before a genetic test, we make sure families are OK if there is uncertainty around a result. Genetic testing is not the crystal ball we wish it could be, and it’s also not capable of detecting everything.

But sometimes, with an in-depth conversation around family history, a child’s symptoms, established screening protocols and the parents’ understandings, genetic testing may be an appropriate option for children.

If parents are concerned or have questions, genetic counseling is always available, even just to discuss concerns and ease worries.

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Posted In Cancer, Cancer Screenings, Children's, Genetics, Pathology