Germline testing for genetic variants associated with breast cancer has been a hot topic since BRCA1 and BRCA2 were identified in the mid-1990s. What was once a cumbersome, expensive, and rarely reimbursed process has become relatively straightforward, more affordable, and widely reimbursed. Does that suggest that all breast cancer patients should undergo genetic germline testing?

Two experts will explore opposing perspectives on that question during the 2024 San Antonio Breast Cancer Symposium®. The session, Debate: All Patients Should be Offered Universal Germline Genetic Testing, will take place Friday, December 13, from 2 to 2:50 p.m. CT in Stars at Night Ballroom 3-4 at the Henry B. Gonzalez Convention Center.

Allison Kurian, MD, MSc, will present the case for testing, while Raymond Kim, MD, PhD, will give the argument against. Dr. Kurian is Professor of Oncology and of Epidemiology and Population Health at Stanford University School of Medicine and Director of the Stanford Women’s Clinical Cancer Genetics Program. Dr. Kim is Medical Director of Cancer Early Detection at Princess Margaret Cancer Centre and the principal investigator of the Ontario Hereditary Cancer Research Network at the Ontario Institute for Cancer Research.

“Genetic testing isn’t that easy, not as simple as ordering a complete blood count or a urine test,” Dr. Kim said. “The testing system isn’t very user friendly to clinicians or to patients and even though insurance does cover it, it is variable on which tests which insurer is going to cover.”

And then there are questions of which genes to test, he said. There is solid evidence for the role BRCA1/2 pathogenic variants play in breast cancer pathogenesis and progression as well as the clinical benefits of BRCA1/2-targeted treatment with poly (ADP-ribose) polymerase, or PARP, inhibitors. The evidence on what to do with variants in many other genes commonly included in test panels is far less clear. Dr. Kim said.

“We test for at least 20 genes on a breast cancer patient and a subset of those genes have been studied very deeply and have very little relevance to breast cancer,” he said. “Lynch syndrome, for one, causes some forms of ovarian cancer but its link to breast cancer is very loose. A lot of the genes we test for may, or may not, be relevant to a breast cancer patient. Telling a patient that you have this mutation but we don’t know what it means in terms of breast cancer risk or treatment is not helpful.”

All true, agreed Dr. Kurian, and the benefits of universal testing for breast cancer patients still outweigh the risks.

“We have seen advances in technology and regulation whereby costs have come down,” she said. “We would like testing to cost $0 and even though it does not, it is much more affordable than it used to be and covered by insurance. And even if a patient has a mutation that does not have a targeted therapy, testing can still tell us whether they have a higher risk for a second breast cancer or another cancer down the road. That would be important for offering personalized screening or prevention.”

Universal testing is also useful for patients’ relatives. Testing positive for mutations relevant to breast or other cancers should trigger testing in relatives, Dr. Kurian noted.

“If those relatives test positive, you can offer them focused screening or prevention before they develop their own cancer,” she explained.

Further, as more individuals develop breast and other cancers at a younger age, the potential benefit of catching unexpected tumors is increasing. Dr. Kurian said. Thus, the risk of finding an uncertain result may be outweighed by the potential benefit of finding a meaningful result – particularly if patients are appropriately counseled that uncertain results should not change their care.

“I don’t know who will win the debate,” Dr. Kim said, “but if we can convince the audience to think twice about the issue, we’ve done the right thing.”