21-Gene Recurrence Score (Oncotype Dx)

• Both tamoxifen and aromatase inhibitors:
  • Have been shown to:
    • Reduce recurrence rates and improve survival in postmenopausal women
• Although chemotherapy has been shown to be beneficial in many patient subsets:
  • The 21-gene recurrence score was developed:
    • To help ascertain which patients with:
      • ER-positive, node-negative breast cancer:
        • Would be most likely to benefit from chemotherapy in addition to adjuvant tamoxifen
• In patients with an intermediate recurrence score:
  • The benefit of chemotherapy is unclear
• The Trial Assigning IndividuaLized Options for Treatment (Rx) [TAILORx] trial:
  • Is a randomized prospective trial:
    • That randomized women with ER-positive breast cancer:
      • With a score of 11 to 25 to:
        • Chemotherapy plus endocrine therapy to endocrine therapy alone
  • This trial is closed to accrual, and the results of this trial for this cohort are pending:
    • However:
      • Outcomes data from a subset of 1626 patients with a recurrence score of less than 10:
        • Were recently published
      • These patients were assigned to:
        • Receive endocrine therapy alone without chemotherapy
      • This study reported a 5-year local recurrence rate of:
        • 0.5% in women with a recurrence score of:
          • Less than 10
      • Furthermore:
        • At 5 years:
          • The invasive disease–free survival was:
            • 93.8%
          • The rate of freedom from recurrence of breast cancer at a distant site was:
            • 99.3%
          • At distant or local site was:
            • 98.7%
          • Overall survival rate of:
            • 98%
  • The authors concluded that a favorable gene expression profile:
    • Is associated with a very low rate of recurrence:
      • At 5 years with endocrine therapy alone
• References:
  • Early Breast Cancer Trialists’ Collaborative Group (EBCTCG), Dowsett M, Forbes JF, et al. Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials. Lancet. 2015;386(10001):1341-1352.
  • Sparano JA, Gray RJ, Makower DF, et al. Prospective validation of a 21-gene expression assay in breast cancer. N Engl J Med. 2015;373(21):2005-2014.

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