
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
...Diagnosis...
...Recommen...
...ent selection, the Expert Panel recomm...
Patients previously treated with ET and a...
...New Recommendations...
...ndation 1.1Patients with locally recurr...
...ecommendation 2.1There are insufficient data at...
...ommendation 3.1Patients with metastatic HER2-ne...
...dation 3.2There is insufficient evidence to...
...commendation 4.1There are insufficient data a...
...mendation 5.1Patients with locally recurrent unre...
...dation 6.1Patients with metastatic...
...n 7.1Patients with metastatic cance...
...tion 8.1Clinicians may test for NTRK fusions in p...
...9.1There are insufficient data to recommend routi...
...on 10.1There are insufficient data to recommend ro...
...on 11.1There are insufficient data...
...Recommendations U...
...presentation of metastasis from brea...
...Recommendation...
...s who are already receiving systemic thera...
...Recommendations...
...ents already receiving systemic therapy for meta...
...oembryonic antigen (CEA), cancer antigen (CA) 15-...
...At-A-Glance...
...Tests Recommended by the ASCO Expert Panel...
...Tests Not Recommended by the ASCO Expert...
ASCO believes that cancer clinical trials are...