ASCO update with TAILORx results: Biomarkers for adjuvant systemic therapy in early-stage invasive BC

M3 India Newsdesk Nov 25, 2019

Based on the TAILORx results, this ASCO update, addresses the use of Oncotype DX in guiding decisions on the use of adjuvant systemic therapy.


The Trial Assigning Individualized Options for Treatment (TAILORx) evaluated the noninferiority of endocrine therapy alone versus chemoendocrine therapy for invasive disease–free survival in women with Oncotype DX scores. As per the consensus, chemoendocrine therapy is recommended in patients with recurrence scores of 26 to 30.


Emerging research in personalised and precision medicine has deciphered the importance of tumour biomarker assays in guiding clinical care. The use of biomarker assay results to tailor treatment decisions has revolutionised health outcomes for cancer patients and has thus unlocked the promise of precision medicine.

In a previous guideline (2016), ASCO had recommended that the biomarker assays Oncotype DX, EndoPredict, PAM50, Breast Cancer Index, and urokinase plasminogen activator and plasminogen activator inhibitor type 1 hold clinical utility to guide decisions on adjuvant systemic therapy for women with early-stage invasive breast cancer.


The new focused ASCO update addresses the use of Oncotype DX in guiding decisions on the use of adjuvant systemic therapy.

For oestrogen receptor and progesterone receptor (ER/PgR)-positive, HER2-negative (node-negative) breast cancer adjuvant chemotherapy reduces the risk of recurrence, with effects that are proportionally greater in younger women but that are little affected by nodal status, grade, or the use of adjuvant endocrine therapy. These findings led to the recommendation of adjuvant chemotherapy for most patients in this group. However, it was found that the majority of patients may receive chemotherapy unnecessarily.

The 21-gene recurrence score assay (Rs), Oncotype DX, is a multigene assay that provides prognostic information in ER/PgR-positive breast cancer.

The recurrence score based on the 21-gene assay ranges from 0 to 100 and is predictive of chemotherapy benefit.

  • A high recurrence score (31 or higher or 26 or higher) is predictive of chemotherapy benefit.
  • A low recurrence score (0 to 10), demonstrates a low probability of distant recurrence (2%) at 10 years that is not likely to be affected by adjuvant chemotherapy.

Though the 21-gene assay is a highly recommended, there have been uncertainties regarding the use of chemotherapy in patients who have a mid-range recurrence score (11 to 25). The Trial Assigning Individualized Options for Treatment (TAILORx) was designed to assess this query.


Key outcomes of the TAILORx trial

The TAILORx trial was a prospective, noninferiority clinical trial that included 6,711 patients with hormone receptor–positive, HER2-negative, axillary node–negative breast cancer and an Oncotype DX recurrence score between 11 and 25.

  • The study population (midrange score of 11 to 25) were randomly assigned to receive either chemoendocrine therapy or endocrine therapy alone.
  • The primary outcome of the trial was invasive disease–free survival, which was defined as freedom from invasive disease recurrence, second primary cancer, or death.
  • Trial results demonstrated that endocrine therapy was noninferior to chemoendocrine therapy (hazard ratio, 1.08; 95% CI, 0.94 to 1.24; P = .26). At 9 years, the two treatment groups (chemoendocrine therapy or endocrine therapy alone) demonstrated the following results:
    • Similar rates of invasive disease–free survival (83.3% in the endocrine-therapy group and 84.3% in the chemoendocrine-therapy group)
    • Freedom from disease recurrence at a distant site (94.5% and 95.0%) or at a distant or local–regional site (92.2% and 92.9%), and overall survival (93.9% and 93.8%).
  • Exploratory analyses of the TAILORx trial indicated that the chemotherapy benefit for invasive disease–free survival may vary with the combination of recurrence score and age; some benefit of chemotherapy was found in women 50 years of age or younger with a recurrence score of 16 to 25.

Based on the TAILORx results, ASCO came out with the following recommendations:

  • For patients with hormone receptor–positive, axillary node–negative breast cancer whose tumours have Oncotype DX recurrence scores of less than 26, there is little to no benefit from chemotherapy, especially for patients older than age 50 years.
  • Clinicians may recommend endocrine therapy alone for women older than age 50 years.
  • For patients 50 years of age or younger with recurrence scores of 16 to 25, clinicians may offer chemoendocrine therapy.
  • Patients with recurrence scores greater than 30 should be considered candidates for chemoendocrine therapy.
  • Based on informal consensus, the panel recommends that oncologists may offer chemoendocrine therapy to these patients with recurrence scores of 26 to 30.

 

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

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