Non-interventional Study to Assess the Effectiveness and Safety of Ribociclib in the Adjuvant Therapy of Hormone Receptor Positive (HR+) HER2-negative Stage II and III Breast Cancer in Real Clinical Practice in Russia

This prospective, observational, multicenter study aims at evaluating the efficacy of adjuvant ribociclib in combination with hormone therapy (aromatase inhibitor ± GnRH aginost) in various subgroups of patients with HR+HER2- stage II-III breast cancer in real clinical practice in Russia. Subgroup division will be based on the tumor grade, lymph node involvement, and the response to test hormone therapy. The study will consist of two cohorts: a prospective one with patients receiving adjuvant therapy with ribociclib combined with Aromatase inhibitors (AI), and a retrospective one with patients receiving adjuvant therapy with AI alone. Thus, both primary data collection and secondary use of data will be organized.