Stereotactic Body Radiotherapy (SBRT) Combined With PD-1 Inhibitor and Chemotherapy in Early-stage Treatment-naive Triple-negative Breast Cancer Patients: A Multicenter Phase III Clinical Study
Triple-negative breast cancer (TNBC) presents significant challenges due to its limited treatment options and poor efficacy. While neoadjuvant chemotherapy has improved breast-conserving rates and extended survival for TNBC patients, this subtype still faces issues such as restricted treatment modalities, low pathological response rates, and unfavorable prognosis compared to other subtypes. Studies like Keynote522 and IMpassion031 have shown that combining chemotherapy with immunotherapy yields a pCR rate of 64.8% in early-stage high-risk TNBC patients, suggesting that such combinations can offer substantial benefits. However, the low immunogenicity of breast cancer and the lack of clear predictive molecular markers for effective immunotherapy result in suboptimal pCR and objective response rates for this group. Radiotherapy has systemic immune regulatory effects by promoting the release of antigens from tumor cells, enhancing T-cell infiltration, and directly killing tumor cells. Therefore, this study aims to investigate the efficacy and safety of stereotactic radiotherapy combined with PD-1 inhibitors and chemotherapy in the neoadjuvant treatment of TNBC.
• 1\. Histologically or cytologically confirmed TNBC (ER-, PR-, HER2-)
• 2\. cT1cN1-2M0 or cT2N0-2M0；（AJCC 7th）
• 3\. ECOG performance status of 0-1;
• 4\. Adequate bone marrow function, defined as: Hb ≥ 9.0 g/dL (90 g/L); ANC ≥ 1,500/mcL (1.5 × 10\^9/L); PLT ≥ 100,000/mcL (100 × 10\^9/L) and no blood transfusion within 3 weeks or growth factor (G-CSF, EPO) therapy within 2 weeks prior to dosing;
• 5\. Adequate liver function, defined as: TBIL ≤ 1.5× upper limit of normal (ULN); If no liver metastases, AST and ALT ≤ 2.5× ULN; if liver metastases are present, AST or ALT ≤ 3.0× ULN; ALP ≤ 1.5× ULN; if liver metastases ≤ 2× ULN; Serum albumin ≥ 30g/L;
• 6\. Adequate coagulation function: INR or PT, APTT ≤ 1.5× ULN. Participants on anticoagulant therapy should have these laboratory indices closely monitored;
• 7\. Adequate renal function, defined as creatinine ≤ 1.5× ULN or Ccr ≥ 50 mL/min calculated using the Cockcroft-Gault formula corrected for body surface area;
• 8\. Baseline left ventricular ejection fraction (LVEF) ≥ 50% measured by multiple-gated acquisition (MUGA) or echocardiogram (ECHO);
• 9\. No severe organic heart disease or arrhythmias;
• 10\. Women of childbearing potential (aged 15-49 years) must have a negative pregnancy test within 7 days before starting treatment. Both male and female participants of reproductive potential must agree to use effective contraceptive measures during the study period and for 3 months after discontinuation of treatment;
• 11\. Voluntary signed informed consent by the study participant.