The Oncotype DX Breast Recurrence Score® test has been developed for patients with early-stage HR+, HER2- breast cancer to:
- Identify those patients who will derive benefit from chemotherapy
- Determine the magnitude of chemotherapy benefit
- Make chemotherapy a personalised treatment
Chemotherapy causes both short- and long-term side effects affecting current and future health, quality of life, family life and work life.1–3 The vast majority of patients with HR+, HER2- early-stage breast cancer do not benefit from adjuvant chemotherapy.4
The Oncotype DX test is the only multigene assay that is both predictive of chemotherapy treatment effect and prognostic of disease outcome5–14
The Oncotype DX test is the only test clinically validated to identify patients likely to benefit from chemotherapy, or not.5–14
Learn more about the difference between prognostic and predictive tests
Prediction of chemotherapy benefit based on prospective clinical trials makes the Oncotype DX test unique
*TAILORx showed that endocrine therapy was non-inferior to chemoendocrine therapy in node-negative patients with Recurrence Score® results 11-25. RxPONDER showed that node-positive postmenopausal patients with Recurrence Score® results 0-25 do not benefit from chemotherapy while premenopausal patients with 1 to 3 positive nodes and RS® results 0-25 have a modest benefit from chemotherapy.
Development of the Oncotype DX Test
The Oncotype DX test was developed to assess disease prognosis and predicts benefit from chemotherapy (CT) in patients with early-stage, HR+, HER2- breast cancer9. Genes were selected accordingly, and the test’s predictive abilities were validated in two-arm retrospective prospective clinical trials (comparing CT+ Endocrine Therapy (ET) versus ET alone): the NSABP B-20 for node-negative patients5,14 and SWOG-8814 for node-positive patients8. The landmark TAILORx study6 showed that ET was non-inferior to CT + ET in patients with node-negative disease and Recurrence Score results 11 to 25. In addition, RxPONDER study11 initial results demonstrated that postmenopausal patients with Recurrence Score results 0-25 can be spared chemotherapy independent of clinical pathologic parameters. This supports earlier research indicating that the majority of patients do not benefit from the addition of chemotherapy.4
The Oncotype DX test was developed to predict chemotherapy benefit based on a unique understanding of tumour biology5,9. The Oncotype DX test quantifies expression of 21 genes in fixed, paraffin-embedded tumour tissue using high-throughput, real-time, reverse transcription-polymerase chain reaction. Three independent breast cancer studies were used to select the panel of 16 cancer-related and five reference genes that are tested in the Oncotype DX assay. Based on the expression levels of the 21 genes, a Recurrence Score result is calculated for each tumour sample.
The Oncotype DX test reveals individual tumour biology based on measuring the expression of 21 genes9
16 Cancer Genes and 5 Reference Genes
What information does the Oncotype DX test provide?
The Oncotype DX test identifies patients who will benefit from adjuvant chemotherapy, or not, by providing three pieces of information: the Recurrence Score result, the risk of distant recurrence, and the estimated chemotherapy benefit.
The Oncotype DX test for node-negative patients
In node-negative, early-stage, HR+, HER2- breast cancer patients, studies including > 95,000 patients have established that the Oncotype DX test consistently identifies the vast majority of patients (80%) who can be spared chemotherapy and the important minority (20%) who may substantially benefit from it.5,6,9,14–16 This includes the largest prospective, randomised adjuvant clinical trial in breast cancer: the landmark TAILORx study, which enrolled more than 10,000 patients.6
Patient selection using the Oncotype DX test in node-negative patients
The Oncotype DX test consistently identifies the ∼80% of HR+/HER2-/EBC patients who can avoid chemotherapy, and 20% of patients for whom it may be life-saving5,6,9,14-16
In the HR+, HER2-, early breast cancer population, about 20% of node-negative patients have Recurrence Score results 26-100. These patients have been shown to derive substantial benefit from chemotherapy5,14. Patients >50 years of age with Recurrence Score results 0-25 have been shown not to benefit from chemotherapy and may forgo the burden and toxicities of this treatment.5-6,8,11-12 For patients 50 or younger, some benefit from chemotherapy may be relevant below the Recurrence Score result of 25 and should be discussed between the treating physician and the patient.5-6,9,14-16
The Oncotype DX test for node-positive patients
The test’s predictive ability in the node-positive setting was validated in the two-arm prospective retrospective clinical trial SWOG-8814 for postmenopausal patients (comparing CT+ Endocrine Therapy (ET) versus ET alone)8. Initial results from the RxPONDER study further refined the chemotherapy benefit estimates for patients with Recurrence Score results 0-25 and 1 to 3 positive nodes. Results from these trials are summarized in the graphic below. Postmenopausal patients with one to three positive lymph nodes and Recurrence Score results 0-25 did not benefit from chemotherapy in addition to endocrine therapy8,11. Premenopausal patients with Recurrence Score results 0-25 and 1 to 3 positive nodes derived a 2.4% chemotherapy benefit in terms of distant recurrence-free interval (DRFI) at 5 years.11-12
Patient selection using the Oncotype DX test in node-positive patients*
*CT benefit expressed in percentage points based on probability of distant recurrence-free interval with/without CT at 5 years. No CT benefit is considered for an absolute benefit <1%. Benefit of chemotherapy for premenopausal N1 patients with RS® results 26-100 has not been formally assessed in a randomised study. The benefit derived from chemotherapy was modest for RS® results 0-13 and 14-25 in the RxPONDER study and it is inferred to be substantial for patients with RS® 26-100.
Guiding treatment with the Oncotype DX test
In summary, thanks to the comprehensive clinical evidence for both node-negative and node-positive patients, the Oncotype DX test can help guide confident chemotherapy treatment decisions.
CT benefit expressed in percentage points based on probability of distant recurrence (N0) or distant recurrence-free interval (N1) with/without CT;
No CT benefit is considered for an absolute benefit <1%;
Node-negative (N0) patients: TAILORx analyses were performed by age and demonstrated patients ≤ 50 years derived some clinically meaningful benefit from CT at 9 years starting with an RS® result of 16;
Node-positive (N1) patients: RxPONDER data were analysed according to menopausal status and demonstrated that premenopausal patients with RS® results 0-25 overall derived benefit from chemotherapy at 5 years.
* Benefit of chemotherapy for premenopausal N1 patients with RS® results 26-100 has not been formally assessed in a randomised study. The benefit derived from chemotherapy was modest for RS results 0-13 and 14-25 in the RxPONDER study and it is inferred to be substantial for patients with RS result 26-100.