2025-01-1920231479-669410.2217/fon-2022-12872-s2.0-85159731947https://doi.org/10.2217/fon-2022-1287https://hdl.handle.net/20.500.14288/26767Background: Ribociclib, palbociclib and abemaciclib are currently approved CDK4/6 inhibitors along with aromatase inhibitors as the first-line standard-of-care for patients with hormone receptor-positive, HER2-negative metastatic breast cancer. Methods: The authors report retrospective real-life data for 600 patients with estrogen receptor- and/or progesterone receptor-positive and HER2-negative metastatic breast cancer who were treated with ribociclib and palbociclib in combination with letrozole. Results & conclusion: The results demonstrated that the combination of palbociclib or ribociclib with letrozole has similar progression-free survival and overall survival benefit in real life for the patient group with similar clinical features. Specifically, endocrine sensitivity may be a factor to be considered in the treatment preference.OncologyJournal Article1744-8301991646700001Q251202