Pyrotinib Maleate Tablets in Combination With Dalpiciclib Isethionate Tablets and Standard Endocrine Therapy

Inclusion Criteria: 1. Female patients aged ≥18 years and ≤75 years old, who have just been treated for breast cancer; 2. Pathological examination confirmed that HR was positive (ER≥10%) and HER2 was low (immunohistochemical staining ICH++ and FISH negative); 3. Patients with invasive breast cancer confirmed by pathological examination (T≥3 or N≥1) who are eligible for neoadjuvant therapy; 4. ECOG score 0\~1 points; 5. Planned to undergo definitive surgical resection of breast cancer, i.e., breast-conserving surgery or total mastectomy, sentinel lymph node (SN) biopsy, or axillary lymph node dissection (ALND); 6. Normal function of major organs, i.e. meeting the following criteria: (1) Blood routine examination standards must meet: ANC ≥1.5×109/L; PLT ≥90×109/L； Hb ≥90g/L； (2) Biochemical examination must meet the following criteria: TBIL ≤upper limit of normal (ULN); ALT and AST ≤ 1.5 times the upper limit of normal (ULN), alkaline phosphatase ≤ 2.5 times the upper limit of normal (ULN), BUN and Cr ≤ 1.5× ULN and creatinine clearance ≥ 50 mL/min (CockcroftGault formula); (3) Cardiac color ultrasound and echocardiography: left ventricular ejection fraction (LVEF≥55%); (4) 18-lead ECG corrected by Fridericia's QT interval (QTcF) in women\< 470 ms; 7. For female patients who are not menopausal or surgically sterilized: agree to abstain from sexual activity or use an effective contraceptive method during the treatment period and for at least 7 months after the last dose of study treatment; 8. Volunteer to join this study and sign the informed consent form. Exclusion Criteria: 1. Those who have a known history of allergy to the drug components of this regimen; 2. Previous anti-tumor therapy or radiotherapy for any malignant tumor (except for cured cervical carcinoma in situ and basal cell carcinoma); 3. Underwent major surgical procedures unrelated to breast cancer within 4 weeks, or patients have not fully recovered from such surgical procedures; 4. Patients with stage IV (metastatic) breast cancer; 5. Inability to swallow, intestinal obstruction, or other factors affecting drug intake and absorption; 6. Severe heart disease or discomfort that cannot be treated; 7. Suffering from mental illness or psychotropic substance abuse and unable to cooperate; 8. Pregnant or lactating female patients; 9. Patients with severe liver and kidney function diseases and hematological diseases; 10. Those who are not suitable for enrollment in the investigator's opinion: such as a history of drug abuse, blood products, anticoagulant drugs and immunological drugs in the past year; Those with poor compliance and refusal to cooperate with treatment; Doctors with severe hypertension and diabetes are not suitable for the study.