Abstract 159P
Background
Multigene prognostic scores (MPS) have been developed for hormone receptor positive (HR+), HER2 negative (HER2-) early breast cancer (eBC) to guide adjuvant treatment decision, i.e. chemotherapy + hormonal treatment (CT+HT) or HT alone. In France, MPS are temporally funded by the ministry of health, pending a real-life evaluation through registry. The aim of our study was to prospectively describe the setting of EndoPredict prescription and the impact on the adjuvant treatment decision. SiMosein is the most important registry of Endopredict real-life data. This ongoing study will allow analysis of the criteria of choice of a MPS like EndoPredict and the impact of the test according to clinicopathological factors.
Methods
The SiMosein registry has prospectively included, between May 2016 and December 2019, clinicopathological and test characteristics of 4766 patients diagnosed with HR+, HER2- eBC, tested with the 12-gene EndoPredict assay. The test was locally performed in 14 laboratories, involved in a national quality control exchange. When available, treatment decision before and after the test was collected.
Results
Patients characteristics: mean age 60 yrs, Tumor characteristics: pT1ab 12,2%, pT1c 54,2%, pT2 31,4% or pT3 1,7%; pN0 69.8%, pN1 28%, pN2 0.4%; invasive carcinoma NOS 81.5%, invasive lobular carcinoma 13.3%, SBR grade 2 76.1%, Ki67>14% 63,2%. All cases were HR+, HER2-. The mean risk of relapse at 10 y, determined by the EPclin score, was 13,5%, 56,4% being of high risk (threshold 10%). The impact on treatment decisions was available for 599 patients: no change, treatment escalation (HT+CT), descalation (HT) in 54,56%, 18,2% and 27.1% of patients respectively.
Conclusions
The use of Endopredict in France is mostly restricted to the intermediate prognostic subgroup of luminal eBC as requested by the French health authority, with a trend to select high risk breast carcinomas. The difficulty to record what the treatment decision would be without the test, illustrates the fact that MPS is now part of the standard of care. In depth analysis of SiMoSein may allow establishment of testing recommendations. In addition, survival monitoring will allow a real-life evaluation of the clinical utility of the test.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
J. Lehmann-Che.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.