ASCO Recommends ESR1 Mutation Testing for Certain Metastatic Breast Cancers
In May 2023, the American Society of Clinical Oncology (ASCO) updated its guidelines to recommend that metastatic, estrogen receptor-positive, HER2-negative breast cancers that grow or come back (recur) during treatment with hormonal therapy — with or without a CDK4/6 inhibitor — should be routinely tested for ESR1 mutations.
ASCO is a national organization of oncologists and other cancer care providers. ASCO guidelines give doctors recommendations for treatments and testing that are supported by much credible research and experience.
The experts who drafted the update said results from the EMERALD trial sent a strong signal that the guidelines needed revising. That trial showed that the hormonal therapy Orserdu (chemical name: elacestrant) could effectively treat advanced-stage, estrogen receptor-positive, HER2-negative breast cancer that has ESR1 mutations.
What are ESR1 mutations?
The ESR1 gene makes proteins that are estrogen receptors. The receptors receive signals from estrogen that tell estrogen receptor-positive breast cancer to grow.
Most metastatic, estrogen receptor-positive breast cancers initially respond to hormonal therapy medicines, but become resistant after a while. Research has shown that when the ESR1 gene develops a change, or mutation, it can cause the breast cancer to become resistant to hormonal therapy.
Updated recommendations
After ESR1 mutation testing, the updated recommendations offer several options for people diagnosed with metastatic, estrogen receptor-positive, HER2-negative breast cancer who want to continue hormonal therapy treatment after hormonal therapy and a CDK4/6 inhibitor.
People who have previously received hormonal therapy and a CDK4/6 inhibitor and have cancer without an ESR1 mutation may receive:
Faslodex (chemical name: fulvestrant) alone
an aromatase inhibitor alone
tamoxifen alone
hormonal therapy plus Piqray (chemical name: alpelisib) if the cancer has a PIK3CA mutation
hormonal therapy plus Afinitor (chemical name: everolimus)
People who have previously received hormonal therapy and a CDK4/6 inhibitor and have cancer with an ESR1 mutation may receive:
Orserdu
other hormonal therapy alone
other hormonal therapy plus Piqray if the cancer also has a PIK3CA mutation
other hormonal therapy plus Afinitor
The experts added that although research shows that Orserdu works as well as or better than the standard of care —hormonal therapy alone — there is currently no data on the safety or benefits of combining Orserdu with targeted therapy medicines.
— Last updated on November 14, 2024 at 9:26 PM