Evaluation of a Genetic Risk Score for Lung Metastasis and Prognosis in Breast Cancer

Inclusion Criteria:

1. Female, age 18 to 70 ;
2. Histopathologically confirmed previously untreated primary early-stage breast cancer, excluding occult breast cancer, inflammatory breast cancer, and Paget's disease of the breast;
3. Histopathologically confirmed primary early-stage breast cancer with no evidence of distant metastasis;
4. At least one measurable target lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1;
5. Eastern Cooperative Oncology Group (ECOG) performance status score ≤ 2;
6. Left ventricular ejection fraction (LVEF) ≥ 55%;
7. Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT) ≤ 2× upper limit of normal (ULN); alkaline phosphatase ≤ 2× ULN; total bilirubin ≤ 2× ULN; serum creatinine ≤ 1.5× ULN;
8. Adequate bone marrow reserve: white blood cell count ≥ 3.0×10⁹/L, absolute neutrophil count ≥ 1.5×10⁹/L, platelet count ≥ 100×10⁹/L, hemoglobin ≥ 90 g/L;
9. Ability to understand the study procedures and willingness to participate voluntarily by signing the informed consent form.

Exclusion Criteria:

1. History of any other malignancy within the past 5 years, except for breast cancer;
2. Evidence of metastatic breast cancer by imaging or pathology;
3. Uncontrolled pleural effusion, pericardial effusion, or ascites;
4. Severe cardiac disease or conditions that would preclude tolerance to chemotherapy, including but not limited to:

   1. Life-threatening arrhythmias or higher-grade atrioventricular block.
   2. Clinically significant valvular heart disease.
   3. Transmural myocardial infarction on electrocardiogram.
   4. Uncontrolled hypertension.
5. Any other condition that, in the investigator's opinion, makes the patient unsuitable for participation in the study.