부산대학교 도서관

Introduction: Male breast cancer, comprising approximately 1% of all breast cancer cases, often leads to the exclusion of male patients as a criterion in clinical trials. While the efficacy of Cyclin-dependent kinases 4 and 6 (CDK 4/6) inhibitors has been established in metastatic hormone receptor-positive (HR +) and human epidermal growth factor receptor 2-negative (HER2 −) breast cancer in women, limited data exist on their effectiveness in male patients.We aimed to evaluate the efficacy and safety of palbociclib or ribociclib in male patients with breast cancer.Methods: This study is a multicenter, retrospective study. We included male patients with HR + and HER2-metastatic breast cancer who received palbociclib or ribociclib as first-line treatment. Our primary endpoints were progression-free survival (PFS), overall response rates (ORR), and drug-related adverse effects.Results: A total of 46 male patients from 27 institutions were enrolled. The median age at initiation of CDK 4/6 inhibitors was 63.64 ± 13.69 years, with a median follow-up of 21.33 (95% CI 14.92–27.74) months. The ORR were 84% for palbociclib and 76.2% for ribociclib. The mPFS for the entire cohort was 28.06 months (95% CI 18.70–37.42). No significant difference in PFS was observed between palbociclib and ribociclib (mPFS: 24.46 months (95% CI 11.51–37.42) vs 28.33 months (95% CI 14.77–41.88), respectively, p = 0.211). No new adverse events were reported.Discussion: This study demonstrates that palbociclib and ribociclib are effective and safe options for first-line treatment in male patients with HR + /HER2 − metastatic breast cancer. However, further prospective studies are warranted to establish their efficacy in this population.