MammaPrint Test Addressed in ASCO Breast Cancer Guideline Update

Vered Stearns, MD

Ian Krop, MD, PhD

New recommendations on the use of the MammaPrint genomic test issued on July 10 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.

The guideline update was published by Krop et al in the Journal of Clinical Oncology^1.

“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.”

MINDACT Trial

This focused update was initiated following the 2016 publication of findings from the MINDACT randomized phase III clinical trial in The New England Journal of Medicine.² 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 that developed the guideline update. “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

Key recommendations of the guideline update follow:

• 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 one to three 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.

ASCO encourages feedback on its guidelines from oncologists, practitioners and, patients through the ASCO Guidelines Wiki at ASCO.org/guidelineswiki. ■

DISCLOSURE: For full disclosures of the guideline authors visit jco.ascopubs.org.

References:

1. Krop I, Ismaila N, Andre F, et al: Use of biomarkers to guide decisions on adjuvant systemic therapy for women with early-stage invasive breast cancer: American Society of Clinical Oncology clinical practice guideline focused update. J Clin Oncol. July 10, 2017 (early release online).

2. Cardoso F, van’t Veer LJ, Bogaerts J, et al: 70-gene signature as an aid to treatment decisions in early-stage breast cancer. N Engl J Med 375 717-729, 2016.