Microarray in Node-Negative and 1 to 3 Positive Lymph Node Disease May Avoid Chemotherapy (MINDACT) Trial

  • 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 and
      • 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
  • While 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:
            • tThe 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 (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

REFERENCES

  1. Cardoso F, van’t Veer LJ, Bogaerts J, et al; MINDACT Investigators. 70-gene signature as an aid to treatment decisions in early-stage breast cancer. N Engl J Med. 2016;375:717-791.
  2. Hudis CA, Dickler M. Editorial: increasing precision in adjuvant therapy for breast cancer. N Engl J Med. 2016;375:790-791.
  3. Paik S, Tang G, Shak S, et al. Gene expression and benefit of chemotherapy in women with node-negative, estrogen receptor-positive breast cancer. J Clin Oncol. 2006;24:3726-3734.

#Arrangoiz #BreastSurgeon #BreastCancer #SurgicalOncologist #CancerSurgeon #Teacher

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