• The MINDACT:
    • Is a randomized, controlled, prospective, phase III, clinical trial:
      • Evaluating the use of a 70-gene signature test (MammaPrint):
        • To aid in directing chemotherapy treatment of women with early-stage breast cancer
      • The goal of this study was:
        • To reduce the overtreatment of early-stage breast cancer
        • To determine if genomic risk (as defined by the 70-gene signature test) can be utilized to predict recurrence and possibly avoid chemotherapy in patients with a low genomic risk
  • Patients were designated as high or low risk for recurrence based on two categories:
    • Clinical / pathologic high-risk features:
      • Positive lymph nodes
      • High-grade tumors
      • T2 tumors
      • Premenopausal diagnosis
    • Genomic risk:
      • As defined by the 70-gene signature test
  • Women who were low risk in both categories:
    • Were not given chemotherapy
  • Women who were high risk in both categories:
    • Were given chemotherapy in addition to endocrine therapy
  • The patients who were deemed discordant between the two categories:
    • Were randomized to use either:
      • Clinical / pathologic or genomic risk to determine chemotherapy recommendations
    • Patients who had a low genomic risk had a 94.7% 5-year distant-metastasis-free survival without chemotherapy:
      • Even in the presence of high-risk clinical / pathologic factors
    • The authors concluded that:
      • Selected patients with low genomic risk may be spared chemotherapy
      • However, in an accompanying editorial:
        • Critics of this trial have noted the survival advantage of 1.5% for high-risk patients who received chemotherapy, and that the study was underpowered to accurately analyze differences between these groups
        • They noted that small differences in survival may be more significant to certain patients:
          • Thus, the decision to forgo standard treatment based on genomic assays is a very personalized decision
  • Similar results were reported with the 21-gene recurrence score assay (e.g., Oncotype DX):
    • With regard to benefit of adjuvant chemotherapy based on genomic risk stratification:
      • For women with estrogen receptor-positive, lymph node-negative breast cancer:
        • Patients with a high recurrence score via the 21-gene recurrence score assay had a significant benefit from chemotherapy with a decrease in 10-year distant recurrence rates, while patients with a low score showed minimal benefit
  • While they differ in the individual genes used to determine their output score:
    • Both of these genomic assays support the concept of directing adjuvant therapy for breast cancer:
      • Based on the biology and genetics of the tumor itself rather than only the clinical and / or pathologic factors


1. Cardoso F, van’t Veer LJ, Bogaerts J, Slaets L, Viale G, Delaloge S, et al; MINDACT Investigators. 70-gene signature as an aid to treatment decisions in early-stage breast cancer. N Engl J Med. 2016;375(8):717-729.

2. Hudis CA, Dickler M. Increasing precision in adjuvant therapy for breast cancer. N Engl J Med. 2016;375(8):790-791.

3. Paik S, Tang G, Shak S, Kim C, Baker J, Kim W, et al. Gene expression and benefit of chemotherapy in women with node-negative, estrogen receptor-positive breast cancer. J Clin Oncol. 2006;24(23):3726-3734.

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