Résumé
CDK4/6 inhibitors have revolutionized the treatment of patients with hormone receptor-positive and HER2-negative metastatic breast cancer. This treatment has become the gold standard in first-line metastatic breast cancer since the demonstration of a significant gain in progression-free survival and overall survival. The optimal treatment after the use of CDK4/6 inhibitors is unknown and is the subject of debate. Several studies have focused on the mechanisms of resistance that occur during endocrine therapy and on treatment-acquired mutations. The use of alpelisib, everolimus, PARP inhibitor in case of BRCA mutation or chemotherapy seems to bring a benefit in second line after a CDK4/6 inhibitor. We will first describe the possible therapeutic strategies and treatment perspectives, and then we will present the results of an observational, multicenter, retrospective study, which will focus on describing the therapeutic strategy after progression on first-line CDK4/6 inhibitor with real-life data.