Genomic Test Guides Chemotherapy Decisions in Older Breast Cancer Population

Findings from a study presented at the 2025 American Society of Clinical Oncology Annual Meeting suggest that a novel genomic assay could support treatment decision-making by identifying older patients who might benefit from chemotherapy for high-risk early-stage breast cancer.

The study, conducted by researchers at Baptist Health Miami Cancer Institute (Miami, FL, USA), evaluated the effectiveness of Agendia’s (Amsterdam, Netherlands) MammaPrint 70-gene assay in informing treatment plans for patients aged 70 and above diagnosed with early-stage breast cancer.

The research utilized data from the FLEX registry, a large, prospective, real-world observational study designed to collect clinical and genomic information from early-stage breast cancer patients who undergo MammaPrint testing. The objective was to understand how the assay’s results influence therapeutic decisions and long-term outcomes across varied clinical environments and demographics. The analysis included over 3000 patients under the age of 70 and slightly more than 1000 patients aged 70 or older, alongside descriptive data on tumor and patient characteristics.

The study found that older patients were significantly less likely than younger ones to have high-grade tumors or lymph node involvement. Moreover, the MammaPrint risk profile indicated a greater share of low genomic risk tumors, including ultralow- and low-risk categories, among the older cohort. Among patients with high-risk tumors, classified as High 1 or High 2 by MammaPrint, older individuals were less likely to receive chemotherapy compared to their younger counterparts. Notably, this trend persisted even when the tumors showed high genomic risk.

In terms of clinical outcomes, older patients with MammaPrint high-risk tumors, particularly those categorized as High 2, tended to experience improved 3-year relapse-free intervals when treated with chemotherapy versus endocrine therapy alone. These findings indicate that MammaPrint can play a valuable role in personalizing chemotherapy decisions for older women by identifying those who may gain a survival benefit from treatment and helping to avoid unnecessary chemotherapy in those with low-risk profiles.

Related Links:
Agendia 
Baptist Health Miami Cancer Institute