Impact of EPclin on adjuvant therapeutic decision making and comparison of EPclin to the PREDICT tool.

Purpose: Genomic signatures, such as EndoPredict®, may help clinicians to decide which adjuvant treatment is the most appropriate. Methods: We propose the EndoPredict® assay for unclear cases of adjuvant treatment in patients treated in our comprehensive cancer center. We prospectively and retrospectively report the decision of adjuvant treatment before and after the EndoPredict® assay, respectively, compared to the PREDICT’s tool scores. Results: From November 2016 to March 2019, 159 breast cancer tumors were analyzed and presented before and after the EndoPredict® assay. Before the EndoPredict® results, clinicians recommended chemotherapy for 57 patients (57/159, 36%). A total of 108 patients (108/159, 68%) were classified as EPclin high-risk score. There was only a slight agreement between clinicians’ decisions and EPclin risk score. The EPclin score led to 37% changes in treatment (59/159); chemotherapy was favored in 80% of cases (47/59). The PREDICT tool recommended chemotherapy for 16 high-risk patients (16/159, 10%). Conclusion: Although genomic tests were developed in order to de-escalate adjuvant treatment, in our comprehensive cancer center the use of the EndoPredict® assay led to an increase in prescribed chemotherapy.