The 21-Gene Recurrence Score Assay (Oncotype DX)

  • The 21-gene recurrence score assay (Oncotype DX):
    • Is a reverse-transcriptase-polymerase-chain-reaction assay of:
      • 16 prospectively selected genes and 5 reference genes
  • Analysis is performed in:
    • Paraffin-embedded tumor tissue
  • This assay was developed from:
    • NSABP B-14 and validated with data and specimens from NSABP B-20
  • It estimates the 10-year risk of distant recurrence:
    • By categorizing results into:
      • Low-risk (RS<18) group
      • Intermediate-risk (RS 18-30) group
      • High-risk (RS>30) group
  • A low recurrence score:
    • Predicts little benefit of chemotherapy
  • The 21-gene recurrence score assay is proven to be prognostic for women with:
    • Node-negative
    • ER-positive breast cancer:
      • Treated with tamoxifen
  • Retrospective data obtained via optional tumor banking:
    • In accordance with the SWOG 8814 trial:
      • Which demonstrated postmenopausal women with node-positive ER-positive tumors achieved:
        • Superior survival when cyclophosphamide, doxorubicin, and fluorouracil was given before tamoxifen
    • The SWOG 8814 trial:
      • Allowed for retrospective assessment of recurrence score on DFS by treatment group
      • Analysis demonstrated the recurrence score results:
        • To be both prognostic and predictive of benefit to adjuvant chemotherapy:
          • As there was no added benefit to adjuvant systemic chemotherapy:
            • In women with low recurrence scores and
            • An improvement of DFS:
              • In those with high recurrence scores
  • These hypothesis-generating results serve as preliminary basis:
    • For the RxPonder trial:
      • Which is currently enrolling as a phase III trial:
        • Randomizing women with hormone receptor-positive and HER2-negative breast cancer involving 1 to 3 lymph nodes and a 21-gene assay recurrence score of 25 or less:
          • To endocrine therapy alone versus chemotherapy followed by endocrine therapy
  • The 21-gene recurrence score:
    • Is not used in patients with HER2-positive breast cancer


  1. Paik S, Shak S, Tang G, et al. A multigene assay to predict recurrence of tamoxifen-treated, node-negative breast cancer. N Engl J Med. 2004;351(27):2817-2826.
  2. 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(23):3726-3734.
  3. Albain KS, Barlow WE, Shak S, et al. Prognostic and predictive value of the 21-gene recurrence score assay in postmenopausal women with node-positive, oestrogen-receptor-positive breast cancer on chemotherapy: a retrospective analysis of a randomised trial. Lancet Oncol. 2010;11(1):55-65.
  4. Ramsey SD, Barlow WE, Gonzalez-Angulo AM, et al. Integrating comparative effectiveness design elements and endpoints into a phase III, randomized clinical trial (SWOG S1007) evaluating oncotypeDX-guided management for women with breast cancer involving lymph nodes. Contemp Clin Trials. 2013;34(1):1-9.

#Arrangoiz #Surgeon #BreastSurgeon #CancerSurgeon #SurgicalOncology #BreastCancer

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