Impact of Propranolol Strategies on Myocardial Injury After Breast Cancer Surgery (B-BIT)

Inclusion Criteria:

1. Female patients aged 20 to 70 years.
2. Patients diagnosed with hypertension or angina who require medication.
3. Patients diagnosed with unilateral, resectable primary breast cancer (ICD-10: C50), Stage I-III.
4. ECOG performance status of 0-1.
5. Patients scheduled to receive standard postoperative treatment (including adjuvant radiotherapy
6. Patients who voluntarily decide to participate and sign the written informed consent form

Exclusion Criteria:

1. Patients with distant metastases.
2. Patients with active infectious diseases, autoimmune diseases (including specific rheumatic diseases), coagulation disorders, or cardiovascular diseases other than hypertension or angina pectoris.

3. Patients with clinically significant hepatic, hematologic, or renal dysfunction, defined as any of the following:

   ① ANC <1,500/mm3

   • Platelets <100,000/mm3

     • Hb <9 g/dL

       • AST and ALT > 2.5 x upper limit of normal (ULN) ⑤ Alkaline phosphatase > 2.5 x ULN ⑥ Total bilirubin > 1 x ULN ⑦ Serum creatinine >1.5 x ULN or estimated creatinine clearance < 60 mL/min (as calculated using the method standard for the institution)
4. Patients with moderate to severe asthma or chronic obstructive pulmonary disease (COPD).
5. Patients who are pregnant or breastfeeding at the time of enrollment.
6. Patients with a history of malignancy within the past 5 years.
7. Patients for whom data collection is considered difficult at the discretion of the investigator.
8. Patients who are unable to understand or complete study questionnaires.
9. Patients who have received β-blockers within 30 days prior to screening.
10. Patients with systolic blood pressure < 100 mmHg or heart rate < 55 beats per minute.