For decades, anthracyclines have played an important role in treating early-stage breast cancer. But whether this class of drugs should continue to be recommended in early disease given that other available therapies are less toxic is a matter of some debate and discussed in a new report by NEJM. Incorporating data from recent trials, two groups of experts present their views on whether anthracyclines should remain in treatment protocols and for which patients.

Determining which patients will benefit most from anthracyclines is critical. Until recently, predictive biomarkers of response have never achieved sufficient accuracy to be incorporated into clinical practice. Emerging data suggest that patients classified as having Luminal B-Type tumors and MammaPrint (MP) High 2 risk appear to derive significant benefit from anthracyclines, whereas those classified as MP High 1 achieve similar outcomes from regimens with or without anthracyclines (J Clin Oncol 2024; 42[S16]: abstract 511). If further validated, the MP assay could support clinical decisions in this setting and improve patient selection.

In a recent analysis of data from the FLEX registry cohort, researchers compared outcomes with TC versus anthracycline-based regimens among 614 people with EBC who had undergone testing with the 70-gene genomic assay MammaPrint (MP). Among the people with MP High Risk 1 category, Luminal type tumors, there was no difference in 3-year disease-free survival with TC compared with anthracycline regimens, whereas survival was significantly better for MP High Risk 2 patients with the inclusion of an anthracycline (J Clin Oncol 2024; 42(S16):abstract 511). This provocative finding at short-term follow-up suggests that genomic assays could eventually have a regimen-defining role.