Agendia, Irvine, Calif, recently shared data that demonstrate the benefits of the MammaPrint 70-gene breast cancer risk-of-recurrence test to significantly change treatment management for patients who had previously received an ‘intermediate’ risk result according to a 21-gene assay.1

MammaPrint analyzes the 70 genes most predictive of breast cancer recurrence and provides a binary low-risk or high-risk result.2,3 The results provide clinically actionable information, causing physicians to either add or remove chemotherapy from their original treatment decision in one out of three cases.

The prospective study of MammaPrint in breast cancer patients with an intermediate recurrence score (Promis) trial was an impact study that enrolled 840 women who had early-stage breast cancer and a 21-gene assay intermediate recurrence score of between 18 and 30 (risk score [RS] 18–30). The trial was conducted across 58 US institutions from May 2012 to December 2015. Each woman had her sample retested with MammaPrint (referred to within the paper as the 70-gene signature test) and treatment recommendations were recorded before and after receipt of the MammaPrint results.

Among the intermediate-risk patients, 45% had a low-risk result with MammaPrint, and 55% had a high-risk result. MammaPrint low- and high-risk results were found at every score across the entire intermediate results range (RS 18–30), with 50% of MammaPrint high-risk results found between the risk scores of 18 and 25, highlighting the lack of correlation between the two tests. Physicians changed their treatment decisions in alignment with the MammaPrint treatment guidance by recommending chemotherapy in 88% of high-risk patients and recommending no chemotherapy in 91% of low-risk patients.

In the study, 29% of patients (108) had chemotherapy removed from their treatment after receiving a MammaPrint low-risk result. For patients classified as MammaPrint high-risk, 37% of patients (171) were recommended to receive chemotherapy, potentially preventing under-treatment.

The Promis findings demonstrate the impact that MammaPrint can have on chemotherapy decisions, and follow the recent American Society of Clinical Oncology (ASCO) breast cancer treatment guideline update, which exclusively recommended the use of MammaPrint in clinically high-risk and lymph-node-positive patients.


William Audeh, MD, MS, Agendia.

“The key outcomes of this study are the confidence that a binary low-risk or high-risk MammaPrint result gave to over three quarters of physicians when making important treatment decisions, and the significant change in those treatment decisions following the reclassification of patients with 21-gene assay intermediate recurrence score,” says William Audeh, MD, MS, chief medical officer at Agendia.

“Promis illustrates the positive effects of having clear, understandable results from a test like MammaPrint when making chemotherapy decisions for breast cancer patients, and suggests that having these results up front can improve physicians’ assurance in treatment decisions where the traditional clinicopathological results are unclear,” adds Audeh.

For more information, visit Agendia.


  1. Tsai M, Lo S, Audeh W. Association of 70-gene signature assay findings with physicians’ treatment guidance for patients with early breast cancer classified as intermediate risk by the 21-gene assay. JAMA Oncol. Published online in advance, October 26, 2017; doi: 10.1001/jamaoncol.2017.3470.
  1. Carlson JJ, Roth J. The impact of the Oncotype Dx breast cancer assay in clinical practice: a systematic review and meta-analysis. Breast Cancer Res Treat. 2013;141(1):13–22; doi: 10.1007/s10549-013-2666-z.
  1. Sparano JA, Gray RJ, Makower DF, et al. Prospective validation of a 21-gene expression assay in breast cancer. N.Eng J Med. 2015;373(21):2005–2014; doi: 10.1056/NEJMoa1510764.