Adjuvant Docetaxel–Cyclophosphamide Versus Anthracycline–Taxane Chemotherapy in Stage I–III HR-Positive/HER2-Negative Breast Cancer: A Real-World Propensity Score Overlap-Weighted Cohort Study

Background/Objectives: The optimal adjuvant chemotherapy regimen remains uncertain for some patients with hormone receptor (HR)-positive/HER2-negative early breast cancer, particularly regarding the incremental benefit of anthracyclines. We compared real-world outcomes with docetaxel-plus-cyclophosphamide (TC) and anthracycline–taxane chemotherapy. Methods: This retrospective single-center cohort included patients with stage I–III HR-positive/HER2-negative breast cancer who underwent surgery and received adjuvant TC or anthracycline–taxane chemotherapy between 2019 and 2025. Patients receiving neoadjuvant systemic therapy were excluded. Disease-free survival (DFS) was the primary outcome and overall survival (OS) the secondary outcome. Propensity score overlap weighting adjusted for measured baseline differences was used; the absolute difference in weighted 3-year DFS was the primary adjusted measure. Results: Among 361 patients, 201 received TC and 160 anthracycline–taxane chemotherapy. The anthracycline–taxane group had higher baseline clinicopathologic risk. Median follow-up was 39.0 months. Twelve DFS events occurred (TC, n = 3; anthracycline–taxane, n = 9). Unadjusted 3-year DFS was 99.0% versus 96.6% (p = 0.096), and 3-year OS was 99.4% versus 99.1% (p = 0.725). The overlap-weighted analysis included 346 patients and achieved adequate covariate balance. Weighted 3-year DFS was 99.2% with TC and 96.5% with anthracycline–taxane chemotherapy, an absolute difference of 2.68 percentage points (95% CI, −1.81 to 10.03). Sensitivity analysis yielded similar results (2.70 percentage points; 95% CI, −1.76 to 9.87). Conclusions: No statistically significant difference in 3-year DFS was demonstrated after adjustment. Limited events and relatively short follow-up preclude conclusions regarding equivalence or noninferiority. These findings support individualized adjuvant chemotherapy selection and warrant confirmation in larger cohorts with longer follow-up.