Cancer and Genetic Testing: Expert Answers Common Questions

Genetic testing is more important now than ever before, as biomarker-driven cancer treatments continue to receive approval across many tumor types. While these personalized treatments are improving outcomes, navigating the landscape of genetic testing can leave patients with questions for their providers.

In a presentation during the 4th Annual School of Nursing Oncology virtual meeting hosted by Physicians’ Education Resource®, LLC (PER®), Emily Mazzei, MS, MPH, CGC, a licensed, certified genetic counselor, provided an overview of current recommendations for genetic counseling in oncology and discussed some of the questions commonly asked.

Determining Testing Type

Mazzei reviewed the difference between somatic testing, also known as germline or tumor testing, and germline testing. Somatic changes are not hereditary, as they occur in the cancer cells themselves, according to Mazzei; germline mutations are present in a patient since birth, since they are passed down from parents to children.

“Depending on what your patient population looks like, you may be seeing that your patients have 1 of these types of genetic tests or both,” Mazzei said. “Somatic testing is becoming a little more commonplace, or [even as] routine as genetic testing. Generally speaking, panel testing is now standard of care.”

In a panel test, patients will be tested for genes associated with their cancer, as well as those that typically fall outside of their cancer type. However, patient choice also plays a role in what kind of testing they will receive, noted Mazzei.

“It also depends on the patient’s preferences. Some want to just focus on the specific cancer type that they have,” Mazzei said. “It also depends on the institution and what the genetic counselors and ordering physicians prefer.”

Genetic Findings Affect Treatment and Family Members

Genetic testing results have become crucial in determining the type of treatment a patient receives. For example, the FDA most recently approved the combination of atezolizumab (Tecentriq) plus cobimetinib (Cotellic) and vemurafenib (Zelboraf) for patients with BRAF V600 mutation—positive melanoma. Only when a mutation or alteration has been detected can a patient be considered for a potential targeted treatment.

Additionally, if a germline mutation is detected in a patient, their immediate family may also be at higher risk for cancer, according to Mazzei. Family members are then faced with the decision of whether they want to undergo testing—that is not an easy choice for many people, Mazzei explained.

“A large part of our role is providing psychosocial support to these patients,” she said. “Essentially, we give them the information they need to help them make the decisions on whether they want to pursue genetic testing when it’s medically indicated.”

The cost of genetic testing is another concern that patients and their family members often have, particularly with regard to whether it will be covered by insurance, Mazzei noted.

“Most insurance companies will cover their genetic counseling, a face-to-face appointment with a genetic counselor,” Mazzei said. “Most insurance companies will cover all, or some, of the genetic or germline testing, if ordered appropriately and clinically indicated.”

As such, Mazzei recommended that prescribing clinicians work closely with genetic counselors to ensure that testing is correctly ordered, thus increasing the chance that it will be covered by their patients’ insurance.

Pediatric Genetic Testing

While the majority of patients who undergo genetic testing for cancer are adults, there are some instances when children under the age of 18 should be tested, according to Mazzei.

Children who should be tested include those with a family history of a pathogenic gene mutation, such as polyposis syndromes, multiple endocrine neoplasia type 2, and Li Fraumeni syndrome (LFS). Those with a personal history or current diagnosis of cancer may also be tested. LFS can lead to potential increased risk of sarcoma, leukemia, and brain tumors, and PTEN Hamartoma Tumor Syndrome can lead to increased risk of macrocephaly, developmental delay, or thyroid cancer.

“The reason for [this testing in this population] is for medical intervention for these specific conditions,” Mazzei said.

However, not everyone under the age of 18 should be tested, despite their relatives’ genetic testing results or cancer history. For example, there is no medical intervention for children with BRCA mutations or Lynch syndrome.

“We also want the patient or the person pursuing genetic testing to be autonomous when making this decision, so that’s why we only recommend testing these childhood conditions and not adult-onset conditions, even though the parents may be wondering whether their child does have that,” Mazzei concluded.

Reference

Mazzei E. Cancer genetic counseling. Presented at: 4th Annual School of Nursing Oncology. July 31-August 1, 2020.