ERBB2 and breast carcinoma: This meta-analysis assessed overall mortality, breast cancer-specific mortality (BCSM) and recurrence outcomes according to RS category.<h4>Methods</h4>Medline, Embase, PubMed and Google Scholar were searched from 1 January to 20 June 2024 for studies reporting outcomes in ER+/HER2- patients treated with CET versus endocrine therapy (ET) alone, stratified by RS.