Efficacy and safety of PD-1/PD-L1 inhibitors in triple-negative breast cancer: a systematic review and meta-analysis

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with a poor prognosis that seriously threatens women's health. There is still a lack of effective therapeutic targets for TNBC treatment. We conducted a meta-analysis to evaluate the efficacy and safety of programmed cell death protein 1 (PD-1)/programmed death protein ligand 1 (PD-L1) inhibitors in combination with chemotherapy for TNBC patients.We searched PubMed, EMBASE, Cochrane Library, and Web of Science for randomized controlled trials (RCTs) related to PD-1/PD-L1 inhibitors combined with chemotherapy. Literature conforming to the research content was identified according to the inclusion and exclusion criteria. The endpoints of efficacy were pathological complete response (pCR), event-free survival (EFS), progression-free survival (PFS), and overall survival (OS). Safety outcomes included adverse events (AEs) of any grade, AEs of grade ≥3, serious AEs, and the incidence of various AEs. We obtained odds ratios (OR), hazard ratio (HR), and 95% confidence interval (CI) for the included studies. Data analysis was performed using Review Manager software (version 5.3).A total of 4468 patients from eight RCTs were analyzed. PD-1/PD-L1 inhibitors in combination with chemotherapy significantly improved pCR (OR, 1.59; 95% CI, 1.28 - 1.98,The combination of PD-1/PD-L1 inhibitors and chemotherapy could improve the survival and prognosis of patients with early and advanced TNBC. Combination treatment may be harmful to the thyroid; therefore, active surveillance and regular follow-up are necessary during treatment.