Discontinuation rate and serious adverse events of chemoimmunotherapy as neoadjuvant treatment for triple-negative breast cancer: a systematic review and meta-analysis

Background: The use of combination of chemotherapy with immune checkpoint inhibitors (ICIs) has shown efficacy in triple-negative breast cancer (TNBC), and chemoimmunotherapy has been introduced in clinical practice. However, limited data are available on the discontinuation rate and serious adverse events of these treatments, particularly in the neoadjuvant setting. Herein, we carried out a comprehensive systematic review and meta-analysis to assess discontinuation rate and serious adverse events of chemoimmunotherapy compared to chemotherapy alone in phase II and III neoadjuvant clinical trials in TNBC. Materials and methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, EMBASE, Cochrane Library, and PubMed/Medline were searched for articles published from June 2008 to May 2023. The outcomes of interest were the discontinuation rate, serious adverse events, and grade 3-4 adverse events. Results: Four studies were included in the analysis. The pooled odds ratios (ORs) for discontinuation rate and serious adverse events were 1.26 [95% confidence interval (CI) 0.78-2.06] and 1.79 (95% CI 1.4-2.28), respectively, in patients receiving chemoimmunotherapy compared to chemotherapy alone as neoadjuvant treatment for TNBC. The chemoimmunotherapy group had a higher risk of grade 3-4 adverse events (OR 1.30, 95% CI 1.07-1.59). The analysis showed substantial heterogeneity, and the risk of discontinuation rate was heavily influenced by the KEYNOTE-522 trial. Conclusions: Our findings highlight the need for clinical trials specifically focused on safety, quality of life, and treatment adherence in TNBC patients receiving neoadjuvant treatment. Close monitoring of tolerability remains crucial in this clinical setting.