21-Gene Recurrence Score (Oncotype Dx)

• The 21-gene recurrence score assay:
  • Is a gene-expression assay:
    • That provides prognostic and predictive information:
      • In hormone receptor positive breast cancer
    • The 21-gene recurrence score:
      • Estimates the likelihood of distant recurrence in women with:
        • ER+ breast cancer with up to 3 lymph nodes positive
      • It also predicts who is more likely to benefit from adjuvant chemotherapy:
        • Patients with more than 3 lymph nodes:
          • Usually receive adjuvant chemotherapy and 21-gene signature assay is not routinely ordered

• The recurrence score based on the 21-gene assay ranges from:
  • 0 to 100:
    • Is predictive of chemotherapy benefit:
      • When it is higher than 25

• 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.
  • Sparano JA et al, N Engl J Med 2018 Sparano JA, Gray RJ, Makower DF, Pritchard KI, Albain KS, Hayes DF, et al. Adjuvant chemotherapy guided by a 21-gene expression assay in breast cancer. N Engl J Med 2018;379(2):111-121.
  • 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.
  • Dowsett M, Cuzick J, Wale C, Forbes J, Mallon EA, Salter J, et al. Prediction of risk of distant recurrence using the 21-gene recurrence score in node-negative and node-positive postmenopausal patients with breast cancer treated with anastrozole or tamoxifen: a TransATAC study. J Clin Oncol. 2010;29(11):1829-1834.
  • Roberts MC, Miller DP, Shak S, Petkov VI. Breast cancer-specific survival in patients with lymph node-positive hormone receptor-positive invasive breast cancer and Oncotype DX Recurrence Score results in the SEER database. Breast Cancer Res Treat. 2017;163(2):303-310.

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