Abstract 2577: Predictive value of multigene assay for chemotherapy benefit in patients with HR+/HER2- early breast cancer

Abstract

Abstract Our risk score based on a combination of multigene expression and clinical variables was validated to predict the risk of distant metastasis in hormone receptor-positive and human epidermal growth factor 2-negative (HR+/HER2-) early breast cancer in our previous study. In addition to its prognostic value, we investigated the predictive value of the risk score for adjuvant chemotherapy benefit in lymph node-negative (LN-), HR+/HER2- breast cancer. 346 patients who treated with hormone therapy (n = 203) alone or hormone therapy plus chemotherapy (n = 143) were classified as low-risk and high-risk group according to the risk score. There was a significant improvement in 10-year distant metastasis-free survival (DMFS) by the addition of adjuvant chemotherapy to hormone therapy in patients with a high risk score (26.5%, P = 0.003), whereas no benefit of chemotherapy was observed in those with a low risk score. The test for interaction between chemotherapy treatment and risk score was significant. The risk score also identified patients who will not benefit from chemotherapy among clinical high-risk group. Our study suggests that the risk score predicts the benefit of adjuvant chemotherapy in LN-, HR+/HER2- breast cancer and the addition of the risk score in the traditional cliniopathological factors may aid the improved treatment decisions. Citation Format: Mi Jeong Kwon. Predictive value of multigene assay for chemotherapy benefit in patients with HR+/HER2- early breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2577.