Treatment Decision Impact of OncotypeDX™ in HR+, N- Breast Cancer Patients

Overview

Primary objective: Determine the impact of the Oncotype DX Recurrence Score (RS) on the treatment recommendation made (administration of chemotherapy or not, in addition to hormonotherapy) in a HR+, N- or pN1(mi), Her2- breast cancer adjuvant population. The impact of Oncotype DX on treatment recommendations can be either a decrease in treatment intensity defined as a change in treatment recommendation from chemotherapy plus hormonal therapy to hormonal therapy alone or an increase in treatment intensity defined as a movement from hormonal therapy alone to the addition of chemotherapy to hormonal therapy. Patients with HR+, N- breast cancer currently represent around 70% of newly diagnosed breast cancers. These are usually good prognosis tumors. However, on the basis of classical clinical and pathological prognostic parameters and markers, the international consensus guidelines recommend treatment with hormone- and chemotherapy in 85-95% of the cases. Considering the natural disease history, such as documented by the EBCTCG meta-analysis, more than 50% of these patients are overtreated, which leads to unnecessary side effects and costs to the health system and to the society. Oncotype DX appears to be well adapted to therapeutic de-escalation as it targets HR+, N- patients and is performed on fixed paraffin embedded tissue (FPET). It is therefore best adapted to daily clinical practice as it does not necessitate any specific surgical procedure or tissue freezing. The prognostic and predictive value of Oncotype DX in ER+, N- patients has been validated on three large adjuvant randomized trials (NASBP B-14, NSABP B-20, and the ATAC study). The test has been commercially available in the USA since 2004, and is being used for more than 50% of the HR+ N- patients in this country. While Oncotype DX has been validated in the USA, it needs to be independently evaluated in France, in the context of the local treatment guidelines and habits, to provide data that are meaningful to the French health system and to the French medical community.