Biomarkers for Systemic Therapy in Metastatic Breast Cancer
Key Points
Key Points
- Testing for PIK3CA and estrogen receptor 1 gene (ESR1) somatic variants and germline BReast CAncer gene 1 (BRCA1), BReast CAncer gene 2 (BRCA2), and partner and localizer of BRCA2 (PALB2) pathogenic variants (mutations) to guide therapy.
- Testing tumors for homologous recombination deficiency, expression of programmed cell death ligand-1 (PD-L1), deficient mismatch repair microsatellite instability (dMMR/MSI), tumor mutational burden (TMB), neurotrophic tyrosine receptor kinase (NTRK) gene fusions, and trophoblast cell-surface antigen 2 (TROP2) expression to determine eligibility for selected treatments.
- The use of cell-free, circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) for monitoring treatment response.
Diagnosis
...Di...
...Recom...
...in treatment selection, the Exper...
...ients previously treated with ET and a CDK4...
...New...
Recommendation 1.1Patients with loc...
Recommendation 2.1There are insufficient dat...
...ecommendation 3.1Patients with metastatic H...
...3.2There is insufficient evidence to supp...
....1There are insufficient data at presen...
...ion 5.1Patients with locally recurre...
...ommendation 6.1Patients with metas...
...ommendation 7.1Patients with metastatic ca...
...endation 8.1Clinicians may test for NTRK...
...mmendation 9.1There are insufficient data to rec...
...ndation 10.1There are insufficient data to recom...
...11.1There are insufficient data to recommend r...
...Recommendations Unch...
...initial presentation of metastasis fro...
...Recommendation for T...
...n patients who are already receiving s...
...Recomme...
...tients already receiving systemic therapy...
...arcinoembryonic antigen (CEA), cancer...
...At-A-Glance Guid...
...rker Tests Recommended by the ASCO Expert PanelH...
...ts Not Recommended by the ASCO Expert P...
...CO believes that cancer clinical trials are vi...