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Genetic Testing Challenges in Oncology: Unnecessary Testing Identifies BRCA2 VUS in 16-Year-Old Girl

Precision Oncology News and My Gene Counsel have partnered to produce the "Genetic Testing Challenges in Oncology" series to highlight real-world issues that genetics experts and medical professionals are encountering as genetic tests are increasingly used in cancer care. Experts submit anonymized case reports to My Gene Counsel, and based on the details in these reports, Precision Oncology News writes a feature that describes the case history, the challenges encountered by professionals in dealing with the case, and strategies they used in response to challenges or errors. The features also include a discussion with My Gene Counsel genetic counseling experts on better approaches that could be considered if similar cases are encountered in the future. In publishing this series, our aim is to educate experts in the field and foster discussion. If you would like to submit a case report, please email [email protected].

What happened?

A gynecologist ordered genetic testing for a 16-year-old girl with an unspecified breast finding and a limited family history of cancer. Genetic testing detected a variant of unknown significance (VUS) in BRCA2. Since this patient had this breast finding, a grandmother with late-onset breast cancer, and the BRCA2 VUS, the gynecologist referred the girl to a breast surgeon.

The surgeon evaluated the girl and concluded that the finding in her breast was benign and explained that medical management decisions shouldn't be based on a VUS finding. However, the surgeon thought it was unusual that the gynecologist had ordered genetic testing for such a young patient and referred her for genetic counseling to discuss the results.  

The genetic counselor contacted the family, and the mother confirmed that the only history of cancer in the family involved the maternal grandmother who was diagnosed with breast cancer at age 60.

Given the limited cancer history in the family, neither the girl nor her relatives would meet the National Comprehensive Cancer Network's guidelines for BRCA1/2 testing for assessing hereditary cancer risk. Genetics professionals tend to defer genetic testing on minors for adult-onset conditions until they reach adulthood, which is the approach uniformly supported by multiple guidelines. Although there may be valid reasons to test a minor, guidelines caution medical professionals to carefully consider the family history and maturity level of minors before conducting such testing and to do so with pretest genetic counseling. Finally, guidelines state that doctors should not make decisions about patient care based on a VUS, a point the breast surgeon had already explained to the mother and daughter. 

How was this case resolved?

The genetic counselor informed the mother of these guidelines, explained what a VUS is, and underscored that variants with unclear links to cancer should not be used to change medical management. Since the gynecologist had ordered genetic testing based on family history information, the genetic counselor offered to see the mother in a formal genetic counseling session.

The mother declined and said she understood that the risk for hereditary cancer was low for her and her daughter. However, she acknowledged being nervous about her daughter's breast finding, and thought it was important to get genetic testing if the gynecologist thought it was needed.

The genetic counselor advised the mother to recontact her if other family members were diagnosed with cancer, since this may change their cancer risk assessment, as well as management recommendations. The breast surgeon suggested the genetic counselor discuss this case with the gynecologist who ordered the genetic test. She visited the office, spoke with a nurse, and left her card, but did not hear back from the gynecologist. The genetic counselor also called the genetic testing lab and told them that the age of the patient should have been a red flag.

Why is this case concerning?

The specifics of the patient's breast finding, which caused the gynecologist to order genetic testing, are unknown. According to Meagan Farmer, a genetic counselor and genetic clinical operations director at My Gene Counsel, it's plausible that the girl had a lump in her breast, for which the gynecologist did a breast exam, but then also ordered a genetic test because her grandmother had breast cancer. It is likely that when testing uncovered a VUS, the gynecologist referred the patient to a breast surgeon due to his or her lack of awareness of guidelines about testing minors and recommendations against acting on VUS.

This case is concerning because medically unnecessary genetic testing was ordered for an adult-onset condition for a minor patient without pretest genetic counseling. Genetics experts tend to avoid testing minors for adult onset conditions. If they do decide to test them, they do so after carefully factoring in the family's cancer history and providing pretest genetic counseling to ensure that the patient understands the risks and benefits.

Still, "the breast surgeon, actually saved the day here. The surgeon appropriately counseled the patient and her mother with respect to the BRCA2 VUS and recognized that the circumstances surrounding the testing of this minor were unusual," Farmer said. “The surgeon’s referral to a genetic counselor also allowed for a second source of accurate information to ensure that the mother and daughter understood the implications of the BRCA2 VUS result.”

What could have been done differently?

There are instances where a medical geneticist or genetic counselor may decide it is appropriate to order genetic risk testing for an adult-onset condition for a minor. Farmer recounted her own experience of ordering targeted BRCA1 testing for a 17-year-old girl whose parent harbored a BRCA1 mutation, which meant that she had a 50 percent chance of inheriting the same mutation. In fact, this was a familial mutation that had been inherited by several relatives.

Farmer's patient had a good understanding of what it would mean to be mutation positive. It would put her at heightened risk for breast, ovarian, and other cancers, which in turn, would put her on a trajectory of increased annual screenings, and later in life, she would have the option to have preventive surgeries to try to reduce her cancer risk.

"The patient in that case wanted to have testing before leaving for college while she was still covered by her parents' health insurance and at home with a built-in support system," recalled Farmer. "We had an in-depth genetic counseling session, and at my request, she took some time after the appointment to think about it further," she said. Upon Farmer's recommendation, the patient even considered speaking to a mental health professional. Based on these interactions, ultimately, Farmer felt comfortable coordinating genetic testing for this young patient.

Had the gynecologist in this case taken a similarly cautious approach, Farmer believes that this 16 year old could have avoided unnecessary genetic testing. "Minors can't make [medical decisions] on their own," Farmer noted. "But you still want to have them assent, even if they can't consent, and involve them" in the decision-making process.

If the gynecologist was unfamiliar with guidelines addressing genetic testing minors for adult-onset conditions, or was uncertain as to how to have an in-depth discussion about the pros and cons of testing, then he or she should have referred the patient to a genetic counselor to have these conversations. According to Farmer, it's unlikely that after taking a family cancer history a genetic counselor would have ordered genetic testing for this patient. "If the family history had been more striking, a genetic counselor would identify the most appropriate person in the family to test, such as someone affected [with cancer] or a closer relative to the affected person," she said.

Although the genetic counselor informed the testing lab that this patient's birth date on the requisition form should have raised red flags, labs defer to the ordering physician and assume that the test is appropriate for the patient. "If a doctor offers a test, it's common to think it's important and indicated," Farmer said. But, even if genetic testing were indicated, there may still be legitimate reasons to wait until the patient reaches adulthood before conducting testing. "A nuanced discussion would be critical," she said.