Objective:

To determine if a genomic test can identify patients with hormone receptor-positive, HER2-negative early breast cancer who are most likely to benefit from anthracycline-containing chemotherapy.

Approach:

• Study Design: Analysis of real-world data from 1,259 patients in the FLEX registry with stage I–III disease, requiring high-risk results on the MammaPrint 70-gene assay and a Luminal B tumor profile on the BluePrint 80-gene test.
• Treatment Comparison: Patients received either an anthracycline- and taxane-based regimen or a taxane/cyclophosphamide regimen after surgery.

Key Findings:

• High-risk category was not uniform; High Risk 2 patients had better invasive disease-free survival with anthracycline treatment.
• High Risk 1 patients had similar outcomes regardless of anthracycline inclusion.
• Standard clinical features did not distinguish patients benefiting from anthracyclines.

Interpretation:

The study illustrates the value of genomic profiling in predicting benefit from specific cancer therapies.

Limitations:

• Analysis based on an observational registry with a median follow-up of just over three years.
• Statistical methods were used to reduce treatment-selection bias, but further validation is needed.

Conclusion:

Additional validation, including analyses from randomized clinical trials, will be necessary before broader clinical adoption.

Sources:

• JCO Precision Oncology