• Female patients aged ≥18 and ≤75 years at the time of signing informed consent.

• ECOG PS status of 0-1.

• Breast cancer assessed as non-metastatic (M0), meeting all of the following:

‣ Clinical stage: Stage IIB, IIIA, IIIB, or IIIC

⁃ Required imaging assessments (within 28 days): Abdominal CT, ECT Bone scan, Chest CT and Brain MRI

• Histologically or pathologically confirmed invasive carcinoma of no special type, with all of the following:

‣ Grade 2 or 3 (confirmed by central laboratory);

⁃ ER-positive (\>1% staining) and/or PR-positive (\>1% staining) by IHC;

⁃ HER2-negative (IHC 0/1+ or HER2/neu FISH ratio ≤1.8);

⁃ Ki-67 ≥15%.

• Patient deemed eligible for radiotherapy after MDT evaluation.

• No prior antitumor therapy within 1 month before enrollment.

• Organ Function Requirements (within 7 days prior to enrollment):

‣ Complete blood count (no transfusion or hematopoietic growth factors within 7 days): ANC ≥1.5×10⁹/L; ALC ≥0.5×10⁹/L; Platelets ≥100×10⁹/L; Hemoglobin ≥90 g/L; WBC ≥3.0×10⁹/L and ≤15×10⁹/L;

⁃ Blood biochemistry (no transfusion/albumin within 7 days): ALT/AST ≤2.5×ULN; ALP ≤2.5×ULN；BUN/Cr ≤1.5×ULN; Cr≥60 mL/min (Cockcroft-Gault formula);

⁃ Coagulation: PT/APTT ≤1.5×ULN; INR ≤1.5×ULN (if no anticoagulant therapy);

⁃ Urinalysis: Urine protein \<2+; if ≥2+, 24-hour urine protein must be ≤1g;

⁃ Thyroid function:TSH ≤1×ULN; if abnormal, normal T3/T4 levels required for eligibility.

• Women of childbearing potential must:

‣ Have a negative serum pregnancy test within 7 days before treatment;

⁃ Use highly effective contraception during the study and for 180 days after the last dose.

• Voluntarily sign informed consent, demonstrate good compliance, and commit to follow-up.