Clinical Characteristics Associated with Efficacy and Prognosis among Patients Treated with PD-1/PD-L1 Inhibitors for Early-stage Triple-negative Breast Cancers: A Meta-Analysis

Objective To assess the efficacy of PD-1/PD-L1 inhibitors combined with chemotherapy for early-stage triple-negative breast cancer (TNBC) patients with different clinical characteristics. Methods Randomized clinical trials for PD-1/PD-L1 inhibitors and chemotherapy combination were included. Pooled analysis of odds ratio (OR) for pathological complete response (pCR) and hazard ratio (HR) for event-free survival (EFS) was conducted overall and for predefined subgroups. Results The combination of immunotherapy and chemotherapy significantly improved pCR rate in early TNBC patients (OR, 1.77), and the incidence of events was significantly reduced by 37%. Lymph node metastasis was associated with more benefits on pCR (OR[N0], 1.29; OR[N+], 2.57; P = 0.01), while earlier T stage was related to more benefits on EFS (HR[T1-T2], 0.48; HR[T3-T4], 0.85; P = 0.05). Conclusion The addition of PD-1/PD-L1 inhibitors to chemotherapy offers improved pCR and EFS in early TNBC patients. T and N stages may have implications for the efficacy.