Recent advancements in genomic testing have significantly refined the prognostic and predictive landscape of breast cancer, providing clinicians with enhanced tools to personalise treatment strategies.
A comprehensive review published in JAMA Oncology examines the clinical utility of three widely used genomic assays—Oncotype DX, MammaPrint, and the Breast Cancer Index (BCI)—in assessing recurrence risk and informing therapeutic decisions.
The integration of genomic assays into clinical care has transformed the management of hormone receptor–positive, HER2-negative early-stage breast cancer.
These assays analyse the expression of specific gene panels to generate individualised risk assessments, guiding decisions regarding adjuvant chemotherapy and extended endocrine therapy.
Key Findings from the Review
The review highlights the value of the three leading assays:
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Oncotype DX: Evaluates the expression of 21 genes to generate a Recurrence Score, stratifying patients into risk categories that predict the likelihood of distant recurrence and potential benefit from chemotherapy.
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MammaPrint: Assesses 70 genes to classify patients into high or low genomic risk groups, aiding decisions about whether to include chemotherapy in the treatment plan.
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Breast Cancer Index (BCI): Combines gene expression data to predict the risk of late distant recurrence and inform the potential benefit of extending endocrine therapy beyond five years.
These assays have demonstrated value in identifying patients who may safely avoid chemotherapy, reducing exposure to associated toxicities without compromising outcomes.
Clinical Implications
The use of genomic tools enables a more personalised approach to breast cancer treatment. By accurately stratifying patients based on recurrence risk, clinicians can tailor adjuvant therapy recommendations—maximising benefit while minimising unnecessary treatment.
Additionally, the ability to predict late recurrence assists in determining the appropriate duration of endocrine therapy, balancing ongoing benefit with potential side effects.
The expanding role of genomic assays in breast cancer care reflects the broader shift towards precision medicine. As evidence supporting their prognostic and predictive value continues to grow, these tools are becoming essential to informed, individualised care—ultimately improving patient outcomes and quality of life.
Paper: Abdou YKantor ORacz JNewman LPierce LJWiner EP. Prognostic and Predictive Insights From Genomic Assays for Breast Cancer in Diverse Populations: A Review. JAMA Oncol. Published online April 03, 2025. doi:10.1001/jamaoncol.2025.0178. Access online here.
