This is a phase II, Single-Arm Clinical Study evaluating the efficacy and safety of a fasting-mimicking diet (FMD) combined with neoadjuvant chemotherapy in patients with ER-positive, HER2-negative breast cancer.
Participants will be assigned to Intervention group: 4-day FMD cycles (827± 100kcal/day on Day 1, 637± 100kcal/day on Days 2-4) synchronized with T-EC chemotherapy.
The primary endpoint is pathological complete response (pCR) rate. Secondary endpoints include metabolic changes, immune markers, quality of life, and safety (CTCAE v5.0). A total patients will be enrolled to detect a 15% pCR improvement (25% vs. 10%, α=0.05, power=80%).