Efficacy and Safety of Postoperative Adjuvant Immunotherapy for Esophageal Cancer: A Systematic Review and Meta-Analysis

Background The use of immune checkpoint inhibitors (ICIs) in the treatment of esophageal cancer has shown promising advancements. However, the efficacy and safety of ICIs in the adjuvant setting following esophagectomy remain inadequately elucidated. Methods We conducted a meta-analysis using Review Manager 5.4.1, based on published clinical trials, to assess the therapeutic efficacy and safety profile of ICIs in adjuvant therapy following esophagectomy for esophageal cancer. The primary endpoints included disease-free survival (DFS), overall survival (OS), and the incidence of adverse events (AEs). Results Four randomized controlled trials (RCTs) were included in the analysis. ICIs demonstrated a significant improvement in DFS in the adjuvant setting (hazard ratio [HR] 0.73, 95% confidence interval [CI]: 0.60–0.89, P < 0.002). However, no statistically significant difference in OS was observed between the ICI and placebo groups (HR = 0.90, 95% CI: 0.76–1.06, P = 0.22). Safety analysis revealed that ICI treatment was associated with a higher incidence of rash (odds ratio [OR] 1.69, 95% CI: 1.24–2.32, P = 0.001), pruritus (OR = 2.22, 95% CI: 1.56–3.14, P < 0.00001), hypothyroidism (OR = 6.03, 95% CI: 3.77–9.63, P < 0.00001), and hyperthyroidism (OR = 5.91, 95% CI: 2.60–13.44, P < 0.0001). Conclusion This is the first meta-analysis evaluating the efficacy and safety of ICIs in the adjuvant treatment of esophageal cancer. The findings suggest that ICIs offer a significant improvement in DFS in patients post-esophagectomy, though no substantial improvement in OS was observed. Notably, the incidence of cutaneous reactions, pruritus, and thyroid dysfunction was higher, underscoring the need for vigilant monitoring in clinical practice.