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 study.1 he prospective randomised 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 and 1 to 3 positive nodes.3 Initial results of the RxPONDER study have been described as practice-changing.3-5
The Recurrence Score® result was a 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.1
RxPONDER study design: node-positive (1-3 nodes) patients with Recurrence Score results 0–25 were randomised to endocrine therapy alone or chemoendocrine therapy3-5
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. Results were presented at the San Antonio Breast Cancer Symposium in 2020 and 2021 as well as published in The New England Journal of Medicine in December 2021.3-5 A total of 5,018 patients were included in the analysis with a 6.1-year median follow up in the latest report.
Based on this interim analysis, the authors concluded that the majority of N1 postmenopausal patients do not benefit from adjuvant chemotherapy, independent of clinical pathological parameters and thus can likely forgo adjuvant chemotherapy based on Recurrence Score® results 0-25.3-5
N1 postmenopausal patients with RS® results 0-25 did not benefit from the addition of chemotherapy to endocrine therapy on any endpoint reported4
Based on this interim analysis, the authors suggested that premenopausal patients with N1 breast cancer and Recurrence Score results 0-25 have a modest benefit from adjuvant chemotherapy.3-5
N1 premenopausal patients with RS® results 0-25 have a modest benefit from the addition of chemotherapy with a 2.4% benefit in terms of 5-year distant recurrence-free interval3-5
Updated RxPONDER results
Professor Catherine Kelly from the Trinity St James Cancer Institute in Dublin presents in the RxPONDER results.
The Oncotype DX Breast Recurrence Score test identifies the vast majority of women who may not receive a benefit from chemotherapy and can ultimately be spared chemotherapy.1
TAILORx's pre-planned analysis established that clinical risk, as assessed by tumour size and grade according to modified Adjuvant!Online, added prognostic value to estimate the clinical outcome of patients receiving endocrine therapy alone; however, it was not associated with response to chemotherapy.3,19
Further exploratory analyses aimed at identifying factors predicting response to chemotherapy. In addition to the Recurrence Score result, age is the only factor that was found to have a correlation with treatment response: patients ≤50 years and with Recurrence Score results 16-25 may benefit from chemotherapy, as detailed in the table below.3,19
