MammaPrint is a Useful Predictor of Chemotherapy Benefit for Estrogen Receptor-Positive (ER+) Breast Cancer Patients

June 13, 2016

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Take-Home Message:

The MammaPrint tumor profiling system accurately predicted the usefulness of chemotherapy on distant metastasis-free survival (DMFS) in women with breast cancer whose disease was ER+ and had zero to three lymph nodes involved.

 

Primary Analysis of the EORTC 10041/ BIG 3-04 MINDACT Study: a Prospective, Randomized Study Evaluating the Clinical Utility of the 70-Gene Signature (MammaPrint) Combined with Common Clinical-Pathological Criteria for Selection of Patients for Adjuvant Chemotherapy in Breast Cancer with 0 to 3 Positive Nodes

Authors: Piccart, M. et. al.
Source: Presentation Abstract, American Association for Cancer Research Annual Meeting, 18 April 2016
https://s3.amazonaws.com/v3-app_crowdc/assets/a/a9/a9f949981f16e94f/S1-05.original.1448391522.pdf

The MammaPrint breast cancer profiling system was developed to predict the benefit of chemotherapy for women with ER+ breast cancer.  The MINDACT study, a prospective trial examining MammaPrint’s effectiveness in women with node-negative and node-positive (1-3 nodes) disease, was eagerly anticipated.

Over 6,000 women from 9 countries were enrolled. Their disease prognoses (high or low risk for recurrence without chemotherapy) were evaluated with the Adjuvant! Online risk assessment tool (a well-established and standard calculator to determine chemotherapy benefit) and with MammaPrint. Women who were seen as “high risk” with both Adjuvant! Online and MammaPrint received endocrine therapy and chemotherapy. Women seen as “low risk” with both tools received endocrine therapy only. Women who were “high risk” with Adjuvant! Online and “low risk” with MammaPrint were then randomized to receive endocrine therapy with or without chemotherapy.

At five years of follow up in this last group, the DMFS was 94.7% in women who were randomized to endocrine therapy alone. This demonstrated the accuracy of MammaPrint in predicting the lack of benefit of chemotherapy for these patients, even with a score of “high” by Adjuvant! Online.

The investigators found that using the MammaPrint resulted in a 46% reduction in the use of chemotherapy, and that the MammaPrint system is useful to assess the presence or absence of chemotherapy benefit among ER+ breast cancer patients with involvement of 0-3 lymph nodes.