The efficacy and safety of antibodies targeting PD-1 for treatment in advanced esophageal cancer: A systematic review and meta-analysis

BACKGROUND: A novel therapy based on programmed death 1 (PD-1) inhibitors has been proved to be effective in advanced esophageal cancer. This article is a meta-analysis that aims to compare the efficacy and safety of anti-PD-1 therapy with chemotherapy in esophageal cancer. PATIENTS AND METHODS: Data were collected from eligible studies searched from PubMed, Web of Science, Cochrane Library, and Embase. Pooled hazard ratio (HR) for overall survival (OS), progression-free survival (PFS), and objective response rate (ORR) was estimated to assess the efficacy of PD-1 inhibitors versus chemotherapy. The subgroup analysis was also performed to evaluate the OS benefits. The OR for the occurrence of treatment-related adverse effects was calculated to assess the safety of anti-PD-1 therapy. RESULTS: A total of 4 studies were analyzed. Compared with patients with chemotherapy, patients with anti-PD-1 therapy had a significant improvement in OS (HR = 0.79, 95% CI: 0.71–0.88, and P<0.001), but no significant relationship was observed in PFS (HR = 0.96, 95% CI: 0.76–1.20, and P = 0.69) and ORR (OR = 1.92, 95% CI: 0.98–3.72, and P = 0.06). A similar result was observed in esophageal squamous cell carcinoma. The significant predictor for treatment benefit alone was histology (P = 0.009). The incidence of grade 3 - 5 treatment-related adverse effects in anti-PD-1 therapy was distinctly lower than that in chemotherapy, but there is no statistical difference in all treatment-related adverse effects. CONCLUSION: Anti-PD-1 therapy significantly prolonged the OS, simultaneously lowered grade 3 - 5 treatment-related adverse effects versus chemotherapy.