Real‐World Efficacy of Metronomic Chemotherapy in Advanced Breast Cancer Across Molecular Subtypes

ABSTRACT Objective Metronomic chemotherapy (mCHT) is widely used in the treatment of breast cancer due to its low toxicity and convenience. However, there remain real‐world studies with satisfactory samples focusing on mCHT in advanced breast cancer. Methods Enrolled patients were assigned into capecitabine‐based (X‐based) group and other mCHT group. Data on baseline characteristics, treatment regimens, and outcomes were extracted from medical records. Kaplan–Meier estimates of progression‐free survival (PFS) and overall survival (OS) were analyzed. Results Totally, 597 patients were included with median follow‐up time of 35.9 months. The median PFS for X‐base group was significantly higher than that in other mCHT group (8.9 vs. 5.9 months, p = 0.004). As salvage therapy, the X‐based group showed significantly higher PFS and OS than the other mCHT group in patients with HR + HER2‐ breast cancer ( p < 0.001 and p = 0.011), especially in those combined with endocrine therapy (ET). Multivariate Cox analysis revealed that additional ET could reduce the disease progression and death risks (HR = 0.60, 95% CI: 0.44–0.81; HR = 0.66, 95% CI: 0.47–0.93). In HER2+ and TNBC populations, the median PFS was higher when used as maintenance therapy compared to salvage therapy (16.0 vs. 7.0 months, p < 0.001; 11.0 vs. 5.0 months, p = 0.030). Conclusion As salvage therapy, mCHT demonstrated significant efficacy advantages in the X‐based group compared to the other mCHT group in patients with HR + HER2‐ breast cancer, especially in those combined with ET. For HER2+ and TNBC patients, mCHT is recommended as maintenance therapy.