- A new study published in the Journal of Clinical Oncology has concluded that patients classified as Low Risk by the MammaPrint genomic platform benefit from adding extended endocrine therapy to their treatment regimens, unlike those classified as UltraLow and High Risk.
- MammaPrint is the most comprehensive standalone genomic test that enables short- and long-term treatment planning for early-stage breast cancer.
Madrid, September 11, 2024.
Personalization of oncological treatments has become a tangible reality thanks to recent advances in precision medicine. One of the greatest challenges when managing breast cancer lies in determining which patients may benefit from extended therapy without risking unnecessary toxicities. Within this context, Agendia’s genomic profiling test MammaPrint has become an essential tool to guide clinical decision-making and improve outcomes for patients.
The challenge of recurrence in breast cancer
Breast cancer, particularly hormone receptor-positive (HR+) breast cancer, has a risk of recurrence that can extend up to 20 years after diagnosis. Despite the advances in its treatment, the uncertainty persists about the optimal duration of extended endocrine therapy (EET). Several studies, including NSABP B-42, recently published in the Journal of Clinical Oncology, have demonstrated that extended letrozole therapy improves disease-free survival (DFS) in some patients, but the key question is: how can we identify those patients that will really benefit from treatment extension?
MammaPrint: beyond clinical risk
MammaPrint is a genomic test for early-stage breast cancer patients that analyzes 70 genes in their tumors and classifies them into different categories according to their High (MP-HR) or Low Risk (MP-LR) of distant recurrence. This tool goes beyond traditional clinical risk assessment by including an in-depth analysis of the tumor’s genetic profile, therefore enabling a more accurate prediction of the potential benefit of EET.
In the NSABP B-42 study, the use of MammaPrint allowed identifying subsets of patients with Low Risk tumors (MP-LR) who benefitted significantly from extended letrozole therapy. A significant 10-year benefit was observed in these patients in terms of disease-free survival (DFS), with a 7.8% increase, as well as in terms of breast cancer-free interval, which increased by 7.0% in these patients. Conversely, patients with High Risk tumors (MP-HR) did not show significant benefits from extended therapy, and neither did those with tumors classified as UltraLow risk; these results underline the importance of accurate patient screening to avoid unnecessary treatments and their associated side effects.
Clinical implications
The results of the NSABP B-42 study highlight the possibilities of the MammaPrint test for guiding decision-making on extending endocrine treatment. This is particularly relevant for patients with Low (non-UltraLow) Risk tumors (MP-LNUL), who showed the highest benefits in terms of improved disease-free survival and breast cancer-free interval.
For oncologists, these findings represent a significant breakthrough towards the ability to personalize therapy and improve clinical outcomes by adapting treatment to each patient’s individual molecular characteristics. Moreover, it allows preventing overtreatment in UltraLow Risk (MP-UL) patients, who may achieve excellent results with little or no extended endocrine therapy.
A personalized approach to managing breast cancer
Integrating tools such as MammaPrint into clinical practice transforms the way breast cancer treatment is addressed. It is not only about prolonging the lives of patients, but also about improving quality of life by minimizing unnecessary treatments and side effects.
A personalized approach allows oncologists to offer more targeted treatments, reduce toxicities, and improve the management of healthcare resources. This is particularly critical within a context where prolonged treatment may lead to cumulative side effects that negatively impact the patients’ quality of life, such as osteoporosis and cardiovascular problems associated with therapies that use aromatase inhibitors such as letrozole.
The utility of the MammaPrint test for guiding decision-making on extending endocrine therapy represents a paradigm shift in the management of early-stage HR+ breast cancer. This study emphasizes the importance of implementing genomic tools in clinical practice to optimize treatment and ensure that each patient receives optimal healthcare based on their specific risk profile.
As we advance towards a more personalized medicine, the integration of technologies such as MammaPrint will be essential to keep improving outcomes and quality of life for breast cancer patients. Collaboration among oncologists, researchers, and the industry is key to continue driving these advances and transforming oncological care for the benefit of all patients.
Rastogi, P. et al. (2024). Utility of the 70-gene MammaPrint assay for prediction of benefit from extended letrozole therapy in the NRG Oncology/NSABP B-42 trial. Journal of Clinical Oncology. https://doi.org/10.1200/JCO.23.01995
