Why ‘All Patients’ With Breast Cancer Should Undergo Germline Testing

All patients who receive a diagnosis of breast cancer should undergo germline genetic testing, one expert urged.

“In my opinion, all patients, in general, should be tested to see if they have [genetic] mutations, both for their family and then also importantly for themselves, because we have these targeted therapies available,” said Dr. Laura Huppert, assistant professor, Division of Hematology/Oncology Department of Medicine at the University of California San Francisco.

Huppert, discussing triple-negative breast cancer during the CURE® Educated Patient® Breast Cancer Summit hosted in tandem with the Miami Breast Cancer Conference, explained that germline testing “is looking at the DNA that you were born with, [such as a] BRCA mutation.” Approximately 5% to 10% of patients with breast cancer “harbor a germline pathogenic or likely pathogenic mutation in BRCA1 and BRCA2 genes,” according to JCO Oncology Practice.

However, the use of germline testing remains low.

Among patients with breast cancer, 26% of female patients and 50% of male patients diagnosed between 2013 and 2019 had undergone germline genetic testing by March 31, 2021, according to a study of more than 1 million patients diagnosed in that timeframe in California and Georgia, results of which were published in JAMA and also found that 6.8% of all patients studied underwent germline genetic testing.

LEARN MORE: Initial Treatment Options for Metastatic Triple Negative Breast Cancer

Experts advised earlier this year — following a panel at the convenance of an American Society of Clinical Oncology (ASCO) and Society of Surgical Oncology panel — that all patients newly diagnosed with stages 1 through 3 or de novo stage 4/metastatic disease who are aged 65 or younger at the time of diagnosis should be offered germline BRCA1/2 testing, according to a report published in the Journal of Clinical Oncology.

The panel also advised that patients who are older than age 65 at the time of diagnosis should be offered testing if they are candidates for PARP inhibitor therapy for early-stage or metastatic disease, have triple-negative disease, have a personal or family history that suggests the possibility of a pathologic variant, were assigned male sex at birth, are of Ashkenazi Jewish ancestry or are members of a population with an increased prevalence of founder mutations, according to the report.

“So, [this is a] big deal. Anyone under 65 tests? Absolutely. And sometimes [I see] it's not done still. … Honestly, my opinion is that everyone should be tested, and other guidelines also suggest that. So I think [it's] just really, really important to get germline genetic testing. And why is that? It's because we have better [treatment] options now,” Huppert said.

The Food and Drug Administration (FDA) approved a pair of PARP inhibitors for patients with breast cancer in 2018: Lynparza (olaparib), was approved by the FDA for the treatment of patients with BRCA-positive, HER2-negative metastatic breast cancer and Talzenna (talazoparib) was approved by the FDA to treat patients with deleterious or suspected deleterious germline BRCA-mutant, HER2-negative locally advanced or metastatic breast cancer.

LEARN MORE: What Patients and Their Families Should Know About Hereditary Breast Cancer

The FDA’s 2022 decision to extend the approved indication of Lynparza as an adjuvant treatment for patients with germline BRCA-mutated HER2-negative high-risk early-stage breast cancer was greeted with enthusiasm by one expert who spoke with CURE® at the time.

“We really like that the unique sensitivity is only there for patients who have these germline mutations,” said Dr. Charles Geyer, co-director of University of Pittsburgh Medical Center’s National Clinical Trials Network and chief scientific officer of the National Surgical Adjuvant Breast and Bowel Project Foundation. “It’s an exciting thing for them. (For the patient it is like), ‘the thing that caused us to get cancer, now we have an effective therapy specific to that that helps us have a much better likelihood of (having an) outcome.’”

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