Efficacy and Safety Evaluation of Combined Preoperative Radiotherapy in Breast Cancer Patients with No Response to Initial Neoadjuvant Chemotherapy
The goal of this clinical trial is to assess whether the addition of preoperative stereotactic body radiation therapy (SBRT) can improve pathological complete response (pCR) rates and safety in breast cancer patients who do not respond to initial neoadjuvant chemotherapy. The main questions it aims to answer are: * Can the combination of SBRT with chemotherapy increase pCR rates in non-responders to initial neoadjuvant chemotherapy? * Does the addition of SBRT to chemotherapy have acceptable safety and tolerability profiles? Participants in this trial will be early or locally advanced breast cancer patients who have shown no response to two cycles of standard neoadjuvant chemotherapy. They will be randomly assigned to either continue with the standard chemotherapy (control group) or receive SBRT in addition to continuing the standard chemotherapy (intervention group). The primary outcome measures will be pCR rate and breast conservation rate. Secondary outcomes will include 3-year local progression-free survival, overall survival, surgical complications, and treatment toxicities.
• Confirmed histologic diagnosis of invasive adenocarcinoma of the breast;
• Stage T1-4N+M0 breast cancer (i.e., stages II and III);
• Breast MRI showing no extracapsular extension of lymph node involvement;
• The standard neoadjuvant chemotherapy regimen has been deemed ineffective after two cycles, with disease assessed as stable (SD) or progressive (PD) according to RECIST 1.1 criteria;
• ECOG performance status score of 0-2;
• Screening laboratory values must meet the following criteria:
• i. White blood cells (WBCs) ≥ 2000/μL ii. Absolute neutrophil count (ANC) ≥ 1500/μL iii. Platelets ≥ 100 x 103/μL iv. Hemoglobin ≥ 11.0 g/dL v. Serum creatinine ≤ 2 mg/dL (or glomerular filtration rate ≥ 40 ml/min) vi. AST ≤ 2.5 x upper limit of normal (ULN) vii. ALT ≤ 2.5 x ULN viii. Total bilirubin within normal limits (except subjects with Gilbert\'s syndrome, who must have total bilirubin \< 3.0 mg/dL) ix. INR ≤ 1.5 x ULN unless participant is receiving anticoagulant therapy as long as PT or aPTT is within therapeutic range of intended use of anticoagulant(s) x. Negative HIV screening test xi. Negative screening tests for Hepatitis B and Hepatitis C. Patients with positive results that do not indicate true active or chronic infection may enroll after discussion and consensus agreement by the treating physician and principal investigator.