This study is a prospective, randomized controlled clinical trial designed to evaluate the efficacy and safety of combining radiotherapy, chemotherapy, and immunotherapy in the neoadjuvant treatment of high-risk HR+/HER2- breast cancer patients.
The study plans to enroll treatment-naïve HR+/HER2- breast cancer patients aged 18-75 with high-risk features (e.g., tumor size ≥3 cm or lymph node positivity, Ki-67 ≥20%). Eligible subjects will be randomized in a 1:1 ratio into two groups: the control group will receive neoadjuvant chemotherapy (nab-paclitaxel followed by epirubicin + cyclophosphamide) in combination with sintilimab immunotherapy; the experimental group will receive the same chemotherapy and immunotherapy regimen with the addition of stereotactic body radiotherapy (SBRT) administered early during treatment, at a prescribed dose of 8 Gy per fraction for 3 fractions, with one fraction per day.
The study has dual primary endpoints: pathological complete response (pCR,) and objective response rate (ORR ). Secondary endpoints include 3-year event-free survival (EFS), incidence of adverse events (CTCAE v5.0), and postoperative cosmetic outcomes of the breast. The study design incorporates hierarchical testing to control for multiplicity, and long-term follow-up is planned to evaluate survival benefits.
The study has been approved by the ethics committee, and all participants are required to provide written informed consent. The results are expected to offer a novel neoadjuvant treatment strategy for high-risk HR+/HER2- breast cancer patients and improve their therapeutic outcomes.
Newly diagnosed, untreated breast cancer;
Age: 18 years ≤ age ≤ 75 years;
Histologically confirmed hormone receptor-positive (HR+) tumor specimen (estrogen receptor [ER] ≥ 10%);
Human epidermal growth factor receptor-2 immunohistochemistry (HER2-IHC) result of 0/1+ or 2+ with negative fluorescence in situ hybridization (FISH) test;
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