Invasive Node-Negative Breast Cancer

Invasive Breast Cancer Assay

Breast cancer is the most common cancer worldwide and the leading cause of cancer death in women. In 2015, more than 234,000 women are anticipated to be diagnosed with invasive breast cancer in the United States.1 Of newly diagnosed patients approximately 50% are lymph-node negative and without evidence of distant metastasis. Prospective randomized trials have demonstrated that patients with estrogen receptor positive (ER+) primary breast cancers benefit from the addition of chemotherapy to adjuvant endocrine therapy, though chemotherapy is not equally efficacious among all patients.2 The Oncotype DX® Breast Recurrence Score enables clinicians to quantify a patient’s risk of disease recurrence and identifies patients who may or may not benefit from the addition of adjuvant chemotherapy to endocrine therapy.

The Oncotype DX Invasive Breast Cancer Assay is a quantitative RT-PCR assay that measures the expression of 21 genes (sixteen cancer-related, five reference genes) in triplicate from fixed paraffin-embedded breast cancer tissue. The assay has been rigorously validated and confirmed in multiple large studies in ER+ node-negative breast cancer patients. The Breast Recurrence Score result is prognostic of the likelihood of distant disease recurrence and is predictive of adjuvant chemotherapy benefit. Utility studies conducted worldwide show that the Recurrence Score result changes adjuvant treatment decisions and health economic studies report the assay to be cost-effective.

There is a continuum of nodal pathology in breast cancer extending from node-negative to node-positive disease, and studies have consistently validated the Oncotype DX Breast Recurrence Score in ER-positive patients along this continuum. The assay has been shown to be both prognostic and predictive of chemotherapy benefit in patients with both node-negative and node-positive disease. Use of the Oncotype DX assay for these patients may serve as a method to identify individuals 1) with lower risk of distant recurrence who are unlikely to benefit significantly from chemotherapy and 2) with a higher risk of recurrence who are likely to derive significant benefit from the addition of adjuvant chemotherapy to hormonal therapy.

Node-Negative Breast Cancer

The Oncotype DX Breast Recurrence Score has been clinically validated in multiple large cohorts of early stage ER+ breast cancer patients with node-negative and node-positive disease. The following summarizes the validation, clinical utility, and health economic evidence in node-negative patient populations.

  • The Oncotype DX Breast Recurrence Score validation has been demonstrated and confirmed in multiple large studies in node-negative breast cancer patients: National Surgical Adjuvant Breast and Bowel Project (NSABP) B-14, NSABP B-20, Arimidex, Tamoxifen, Alone or in Combination) ATAC, Kaiser case control, Japan Breast Cancer Translational Research Group, and Eastern Cooperative Oncology Group (ECOG) 2197.
  • Validation studies consistently met their primary endpoint, and demonstrate that the Breast Recurrence Score result is prognostic of the likelihood of distant recurrence and is predictive of adjuvant chemotherapy benefit. The assay also provides insight into the unique biology of each patient’s tumor not captured by other clinical or pathologic measures.
  • Multiple clinical utility studies worldwide demonstrate that the Breast Recurrence Score result changes adjuvant treatment recommendations and health economic studies show the assay to be cost- effective and or cost saving.
  • As a result of the significant body of consistent evidence supporting the Oncotype DX Breast Recurrence Score it has been incorporated into multiple guidelines including NCCN, ASCO, NICE, St. Gallen and ESMO.

 

REFERENCES
1. Cancer Facts and Figures 2015.
2. Early Breast Cancer Trialists' Collaborative Group (EBCTCG). Comparisons between different polychemotherapy regimens for early breast cancer: meta-analyses of long-term outcome among 100,000 women in 123 randomised trials. Lancet. 2012; 379(9814):432-44.

 

Next: Clinical Validation