Ribociclib plus endocrine therapy in bone marrow visceral crisis: challenging the chemotherapy paradigm in luminal metastatic breast cancer—a case report

CDK4/6 inhibitors in combination with endocrine therapy may constitute an effective and well-tolerated alternative to chemotherapy in HR+/HER2- metastatic breast cancer presenting with visceral crisis, including hematologic compromise due to bone marrow involvement. This case underscores the need to reconsider current treatment algorithms to include targeted therapies as a viable and effective option in acute and life-threatening presentations of HR+/HER2- metastatic breast cancer.