Assessing Combined SBRT in Breast Cancer Non-Responders to 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.