Neoadjuvant Treatment of Triple-Negative Breast Cancer with Stereotactic Radiotherapy, PD-1 Monoclonal Antibody, and Chemotherapy

Inclusion criteria

Signed written informed consent prior to enrollment

Age ≥ 18 years

ECOG PS score 0-1

Newly diagnosed T1c N1-2 or T2-3 N0-2 breast cancer

Triple-negative breast cancer with PD-L1 CPS < 10

Hemoglobin ≥ 10.0 g/dl, neutrophils ≥ 1.5 × 10⁹/L, platelet count ≥ 100 × 10⁹/L

BUN ≤ 1.5 × upper limit of normal (ULN), creatinine ≤ 1.5 × ULN

Serum bilirubin ≤ 1.5 × ULN, alkaline phosphatase (AKP), AST, and ALT ≤ 2.5 × ULN

Women of childbearing potential must be willing to use contraception during the study

Negative serum or urine pregnancy test within 7 days prior to treatment

Exclusion criteria

Occult breast cancer

Bilateral breast cancer

Breast tumor unsuitable for SBRT

Unable to undergo MRI scanning

History of other malignancies that may affect survival

Active autoimmune disease or history of autoimmune disease

Current use of immunosuppressants or systemic steroids (within 2 weeks prior to enrollment)

Known allergy to any component of the investigational drugs

Uncontrolled cardiac symptoms or diseases

Active infection or unexplained fever > 38.5°C during screening/before first dose

Other factors likely to cause early study termination (e.g., serious concurrent illnesses, significant lab abnormalities, or social/family circumstances affecting safety/data collection)