Revisiting the definition of estrogen receptor positivity in HER2-negative primary breast cancer

ConclusionStage II or III HER2-negative primary breast cancer with ER  <  10% behaves clinically like triple-negative breast cancer in terms of pCR and survival outcomes and patients with such tumors may have a limited benefit from adjuvant hormonal therapy. It may be more clinically relevant to define triple-negative breast cancer as HER2-negative breast cancer with <10%, rather than  <1%, of ER and/or progesterone receptor expression.
Source: Annals of Oncology - Category: Cancer & Oncology Source Type: research