Impact of the EndoPredict-clin score on risk stratification in ER-positive, HER2-negative breast cancer after considering clinical guidelines.

542 Background: Many ER-positive, HER2-negative breast cancer patients are treated by adjuvant chemotherapy according to current clinical guidelines. We retrospectively assessed whether the combined gene expression/ clinicopathological EndoPredict-clin (EPclin) score improved the accuracy of risk classification in addition to considering clinical guidelines. Methods: Three clinical breast cancer guidelines (National Comprehensive Cancer Center Network (NCCN), German S3 and St. Gallen 2011), and the EPclin score - assessed by quantitative RT-PCR in formalin-fixed paraffin-embedded tissue - were used to assign risk groups in 1,702 ER-positive, HER2-negative breast cancer patients from two ra…