The Recurrence Score® result has been proven to be predictive of chemotherapy benefit for HR+, HER2-, node-positive postmenopausal patients in the retrospective SWOG-8814 study1. The prospective randomized trial RxPONDER including more than 5 000 patients was designed to refine chemotherapy benefit estimates for HR+, HER2- patients with Recurrence Score results 0-25 with 1 to 3 positive nodes3. Initial results of the RxPONDER study have been described as practice-changing.2
- Postmenopausal women with 1-3 positive nodes and Recurrence Score® results 0-25 can forgo adjuvant chemotherapy regardless of the number of affected nodes, tumour grade and size3
- Premenopausal women with 1 to 3 positive nodes and Recurrence Score results 0-25 have a 2.9% benefit from chemotherapy based on distant recurrence at 5 years3
The retrospective analysis of the SWOG-8814 trial, in which HR+, node-positive, postmenopausal patients were randomized to chemoendocrine therapy vs endocrine therapy alone, established that the Recurrence Score result is predictive of chemotherapy benefit in node-positive patients1, consistent with the findings in the node-negative setting in the NSABP B-20 clinical trial.4-5
The Recurrence Score result was a strong predictive factor of chemotherapy benefit for disease-free survival (P interaction = 0.029), overall survival and breast cancer-specific survival in the first five years.
RxPONDER (SWOG S1007) is an ongoing prospective, randomized trial to determine the effect of chemotherapy in patients with hormone receptor-positive (HR+), HER2-negative breast cancer with 1-3 positive axillary lymph nodes, including micrometastases3
. For this purpose, eligible patients with Recurrence Score®
(RS) results 0-25 were randomized to adjuvant chemotherapy followed by endocrine therapy or to endocrine therapy alone3
RxPONDER study design: node-positive (1-3 nodes) patients with Recurrence Score results 0–25 were randomized to endocrine therapy alone or chemoendocrine therapy3
At a prespecified interim analysis in September 2020, the Data Safety Monitoring Committee advised the study investigators to report the available findings of the clinical trial. Preliminary results were presented at the San Antonio Breast Cancer Symposium on 10 December 20203. A total of 5,015 patients were included in the analysis with a 5.1-year median follow up.
Stratified by menopausal status, 5-year invasive disease-free survival (IDFS) was similar for postmenopausal patients treated with endocrine therapy with or without chemotherapy (hazard ratio 0.97; 95% CI 0.78 to 1.22; p=.82)3. The lack of benefit from chemotherapy was observed regardless of clinicopathological factors such as patient age, tumour grade, tumour size, number of positive nodes, type of surgery, or Recurrence Score group (results 0-13 vs results 14-25)3. No significant difference in overall survival (OS) was observed (5-year OS 96.2% for CET vs 96.1% for ET; hazard ratio 0.96; 95% CI: 0.70-1.31; p=.79).3
Based on this interim analysis, the authors concluded that N1 postmenopausal patients with Recurrence Score® results 0-25 do not benefit from adjuvant chemotherapy, regardless of clinical pathological parameters and can likely safely forgo chemotherapy without compromising IDFS.3
N1 postmenopausal patients with RS® results 0-25 do not benefit from the addition of chemotherapy to endocrine therapy in any endpoint reported3
For premenopausal patients, 5-year invasive disease-free survival (IDFS) differed significantly by treatment (chemotherapy hazard ratio 0.54; 95% CI 0.38 to 0.76; p=.0004)3, with a 2.9% absolute difference in rate of distant recurrence as first site. The benefit of chemotherapy was observed regardless of clinicopathological factors such as patient age, tumour grade, tumour size, number of positive nodes, type of surgery, or Recurrence Score group (RS 0-13 vs RS 14-25)3. Notably, 5-year overall survival (OS) was significantly greater in premenopausal patients treated with chemotherapy plus endocrine therapy vs endocrine therapy alone (98.6% vs 97.3%; hazard ratio 0.47; 95% CI: 0.24-0.94; p=.032).3
Based on this interim analysis, the authors suggested that premenopausal patients with N1 breast cancer and Recurrence Score results 0-25 likely benefit significantly from adjuvant chemotherapy. Data for the secondary endpoints will be reported in the future.3
N1 premenopausal patients with RS® results 0-25 significantly benefit from chemotherapy with a 2.9% benefit based on distant recurrence3
Why choose the Oncotype DX Breast Recurrence Score test?
The Oncotype DX Breast Recurrence Score test identifies the majority of node-positive women who will not benefit from and can safely be spared chemotherapy.1
- Oncotype DX is the only multigene assay proven to predict chemotherapy benefit regardless of nodal status.1,4-5 Find out more about the difference between prognostic and predictive
- The Oncotype DX test has been studied in more than 96,000 breast cancer patients in over 79 registry and clinical trials.1-2,4-9,11-12
- There is a consistent and large body of evidence across randomized, prospective and retrospective studies and real-world evidence.1-2,4-9,11-12
- The Oncotype DX Breast Recurrence Score test has been incorporated into major clinical practice guidelines worldwide.13-18