Efficacy and safety of thymosin combined with anticancer therapy for esophageal cancer: a systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE

This study aims to comprehensively evaluate the clinical efficacy, impact on immune function, and safety of thymosin combined with anticancer therapy for esophageal cancer (EC) patients.

METHODS

We systematically searched Chinese and English databases to identify randomized controlled trials (RCTs) evaluating thymosin combined with standard anticancer therapy for EC. Meta-analysis was performed using Review Manager 5.4. Sensitivity analysis and publication bias assessment were conducted using Stata 18.0. TSA was further employed to validate the reliability of primary outcomes. Evidence quality was assessed using GRADE system.

RESULTS

A total of 18 RCTs (1,272 patients) were included. Meta-analysis demonstrated that compared with standard anticancer therapy alone, combined thymosin therapy significantly improved Objective Response Rate (ORR) (RR = 1.27, 95% CI: 1.17-1.39) and Disease Control Rate (DCR) (RR = 1.13, 95% CI: 1.07-1.19), and improved 1-year survival rate (RR = 1.36, 95% CI: 1.19-1.56), 2-year survival rate (RR = 1.47, 95% CI: 1.12-1.92), and 3-year survival rate (RR = 1.42, 95% CI: 1.07-1.90). Regarding immune function, the treatment group exhibited a higher CD3+ T lymphocyte ratio (CD3+%) (MD = 17.56, 95% CI: 13.63-21.50), CD4+ T lymphocyte ratio (CD4+%) (MD = 12.81, 95% CI: 10.76-14.87), CD4+/CD8+ ratio (MD = 0.71, 95% CI: 0.61 - 0.81), and natural killer (NK) cell level (MD = 4.02, 95% CI: 3.06-4.97) were significantly elevated. Regarding safety, combination therapy significantly reduced incidence of treatment-related adverse effects, including gastrointestinal reactions (nausea and vomiting) (RR = 0.69, 95% CI: 0.60-0.79), leukopenia (RR = 0.52, 95% CI: 0.43-0.63), radiation esophagitis (RR = 0.63, 95% CI: 0.44-0.90), and radiation pneumonitis (RR = 0.37, 95% CI: 0.22-0.62). However, methodological quality of included RCTs was limited, and a comprehensive safety assessment is limited by lack of data on thymosin-specific side effects. GRADE assessment indicates that the quality of evidence for most outcomes ranges from "very low" to "low."

CONCLUSION

Current evidence suggests that combination of thymosin with anticancer therapy for EC may enhance antitumor efficacy, improve patients' immune function, and reduce toxicity associated with conventional treatments. However, given limited quality of RCTs and presence of publication bias, these conclusions require validation through additional large-scale, high-quality prospective research.

SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/prospero/, identifier PROSPERO CRD420261282381.