HIỆU QUẢ ĐIỀU TRỊ THUỐC ỨC CHẾ CDK4/6 KẾT HỢP NỘI TIẾT TRÊN BỆNH NHÂN UNG THƯ VÚ LỚN TUỔI TÁI PHÁT, DI CĂN THỤ THỂ NỘI TIẾT DƯƠNG TÍNH, HER2 ÂM TÍNH

Abstract

Objectives: Elderly breast cancer patients are often underrepresented in clinical trials, resulting in limited evidence for this population. Therefore, real-world data are essential to support treatment decisions in elderly patients with recurrent or metastatic breast cancer characterized  HR+, HER2-. This study aims to describe the clinical and paraclinical characteristics and to evaluate the effectiveness of endocrine therapy combined with CDK4/6 inhibitors in patients aged ≥ 65 years with recurrent or metastatic HR+, HER2- breast cancer in clinical practice. Patients and methods: The study was designed as a descriptive study with both retrospective and prospective components, conducted on 81 patients aged ≥65 years who were diagnosed with recurrent, metastatic HR+/HER2- subtype and treated at K Hospital between January 2020 and May 2025. Result: The mean age at diagnosis was 70.0 years. The overall response rate (ORR) was 49.4%, comprising a complete response in 2.5% of patients and a partial response in 46.9%. Stable disease was observed in 32.1% of cases, resulting in a clinical benefit rate (CBR) of 81.5%. The median progression-free survival (PFS) was 15 months. There was no significant difference in PFS between patients receiving ribociclib and those receiving palbociclib, nor across different starting dose levels. Regarding safety, the most frequent adverse event was grade 3–4 neutropenia, occurring in 56.5% of treatment cycles. Grade 3–4 thrombocytopenia was reported in 2.8% of cycles. Anemia occurred predominantly at grade 1–2 (35%), with no grade 3–4 cases observed. Elevated liver enzymes were detected in 7% of patients at grade 1–2, and no grade 3–4 hepatotoxicity was documented. Conclusion: Endocrine therapy combined with CDK4/6 inhibitors in elderly patients with HR+/HER2- breast cancer demonstrated high efficacy in disease control and prolonged progression-free survival. The findings support the recommended starting doses of ribociclib 600 mg and palbociclib 125 mg. However, dose reductions to 400 mg for ribociclib or 100 mg for palbociclib may be considered in elderly patients to improve tolerability without compromising treatment efficacy.