Transferring MINDACT to Daily Routine: Implementation of the 70-Gene Signature in Luminal Early Breast Cancer – Results from a Prospective Registry of the Austrian Group Medical Tumor Therapy (AGMT)

Abstract

Background: For hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative early breast cancer (EBC), adjuvant chemotherapy (ACT) is recommended in the case of high-risk features only. The MINDACT trial showed that patients with high clinical risk (CR) but low genomic risk (GR) defined by the 70-gene signature (MammaPrint®; 70-GS) did not benefit from ACT. In this registry, we investigated the frequency and feasibility of 70-GS and concurrent 80-gene subtyping (BluePrint®) use in HR-positive, HER2-negative EBC. Furthermore, we recorded the frequency of ACT recommendation and the adherence to it when the “MINDACT strategy” was used. Methods: This prospective registry included patients from 2 Austrian cancer centers. Similar to MINDACT, a modified version of Adjuvant!Online was used to determine CR, and 70-GC was used to determine GR in high-CR patients. ACT was recommended to patients with high CR and high GR. Results: Of 224 enrolled patients, 76 (33.9%) had high CR and 67 (88.2%) received genomic testing. Of those, 43 (64.2%) were classified as low and 24 (35.8%) as high GR, respectively. All 24 patients with high CR and GR (10.7% of all patients) received the recommendation for ACT, but ACT was started in only 15 patients (62.5%). The median time from surgery to the start of ACT was 45 days (range 32–68), and the median time from test decision to the test result was 15 days (range 9–56). Conclusion: We showed that the results of the MINDACT trial are reproducible in an Austrian population. Incorporating 70-GS into the daily clinical routine is feasible and mostly accepted by physicians for the guidance of treatment recommendations.