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New recommendations on the use of the MammaPrint genomic test will help guide decisions on adjuvant systemic therapy for women with early breast cancer. The recommendations update the ASCO 2016 clinical practice guideline on the use of biomarkers in these patients.


"Some women with breast cancer are more likely to have a recurrence of cancer and need to receive chemotherapy to lower this risk," said Vered Stearns, MD, Co-Chair of the Expert Panel that developed the guideline update. "The MammaPrint test can now be added to the list of tests that help clinicians identify women who need chemotherapy and those who do not."


This focused update was initiated following the 2016 publication of findings from the MINDACT randomized phase III clinical trial (N Engl J Med 2016;375:717-729). The study explored the use of the MammaPrint 70-gene test to guide treatment decisions in more than 6,500 women with early-stage breast cancer.


"Certain women with a low-risk score on MammaPrint may not need chemotherapy and may be spared its side effects," said Ian Krop, MD, PhD, Co-Chair of the Expert Panel. "However, this test is not suitable for all women with early breast cancer. For example, we do not recommend it for women with HER2-positive tumors or those with triple-negative breast tumors."


Key recommendations of the guideline update include:


* The use of the MammaPrint assay can be considered to inform decisions on adjuvant systemic chemotherapy in women with estrogen receptor-positive or progesterone receptor-positive, HER2-negative, node-negative breast cancer who are at a high clinical risk of recurrence per MINDACT categorization (details provided in Data Supplement published with this guideline).


* MammaPrint can also be considered in women with estrogen receptor-positive or progesterone receptor-positive, HER2-negative breast cancer with 1-3 positive lymph nodes who are at a high clinical risk of recurrence.


* Women meeting either of these criteria whose MammaPrint score is low may be treated with hormone therapy alone, as it is unlikely that chemotherapy will provide substantial additional benefits.


* MammaPrint should not be used in women who have a low clinical risk for recurrence per MINDACT categorization.



The guideline update is available at Information for patients about breast cancer is available at


ASCO encourages feedback on its guidelines from oncologists, practitioners, and patients through the ASCO Guidelines Wiki at