Genomic testing should be used judiciously in early-stage breast cancer
NEW YORK — Not every patient with early-stage breast cancer should undergo genomic testing, and oncologists should be aware of the data to inform who should and should not receive genomic testing, according to a moderator at Chemotherapy Foundation Symposium.
“Say a woman comes in to an oncologist’s office with a 2-cm tumor [that is] grade 1, node-negative and ER-positive, she probably can get away with just hormone therapy alone,” Adam M. Brufsky, MD, PhD, co-director of the comprehensive breast cancer center and associate chief of hematology/oncology at the University of Pittsburgh, told HemOnc Today. “This is something we have to think about. Instead of just doing the tests all the time on everybody, we should be more judicious [about who we test].”
Brufsky, a HemOnc Today Editorial Board Member, moderated a crossfire at the Chemotherapy Foundation Symposium between breast cancer experts who discussed which genomic tests they recommend and some of the differences between the tests.
The question of which genomic test oncologists should consider using is an interesting one to Brufsky.
“As someone who has been interested in this topic for almost 15 to 20 years, it’s a matter of the degree of precision the tests offer,” he said. “For example, the 21-gene assay is a first-generation test that ... no one had been able to do with that precision. The problem with the tests is they picked genes that were known in 2000 and haven’t changed them since. So, although those genes are important, a lot of what the 21-gene assay does, potentially can be replicated by really good immunohistochemistry.”
Assays including the 21-gene assay (Oncotype DX, Genomic Health), 70-gene assay (MammaPrint, Agendia) and breast cancer prognostic gene signature assay (Prosigna, NanoString Technologies) are all good to use for tests, according to Brufsky. But, he said, the decision should come down to the degrees of precision for each test.
“Clearly, at least to me right now, the 70-gene assay has the most prospective data,” he said. “We don’t have the other subgroups of TAILORx, so right now we have prospective data on 6,700 women who if they are high clinical risk, and if they have a low risk 70-gene assay on endocrine therapy alone, they have a 5-year DFS of 95%.”
Brufsky reiterated the importance of staying up-to-date on the data, and that not every patient needs to undergo genomic testing.
He gave an example of how, traditionally, older women unfit for chemotherapy do not undergo genetic tests. “I think that this can really apply to any age, 3 cm or below, node-negative disease,” he said. Additionally, low-risk patients — possibly 20% to 30% of patients — most likely do not need to be tested, according to Brufsky.
“You really have to choose,” he said. “I think the payer’s like that, the patient’s like that, and I think we’re a little hesitant sometimes to say to [our patients], ‘Listen, you have a tumor that’s just going to do great, no matter what we do, and you don’t need to be genomically tested.’” – by Ryan McDonald
Brufsky AM, et al. Medical Crossfire: How Should Genomic Testing Be Used in Early-Stage Breast Cancer? Presented at: Chemotherapy Foundation Symposium; Nov. 8-10, 2017; New York.
Disclosures: Brufsky reports serving as a consultant for Agendia and Novartis.