Herbal Medicines for the Improvement of Immune Function in Patients With Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis.

Background: Lung cancer has the highest mortality rate of all cancers worldwide. Conserving the immune system and reducing the adverse events associated with cancer treatment have become increasingly important. Our study aimed to investigate the immunological effects of herbal medicine (HM) alone, independent of conventional cancer therapies, in patients with non-small cell lung cancer (NSCLC). Methods: We searched 8 databases for articles published until March 2023. Bias risk was assessed using RevMan 5.4. Meta-analyses of CD4+ and CD8+ levels reported in the included RCTs were also performed. Results: A total of 610 patients from 5 RCTs were included in the analysis. Immune markers in the peripheral blood of patients treated with HM alone were compared with those in the control group. As a result of meta-analyses, CD4+ (three studies; mean difference(MD) = 5.21, 95 confidence interval (CI) [3.26, 7.27], I² = 61%, n = 428) and CD4+/CD8+ (two studies; MD = 0.22, 95% CI [0.18, 0.26], I² = 0%, n = 278) significantly increased in the treatment group, while CD8+ levels (three studies; MD = -3.04, 95% CI [-5.80, -0.29], I² = 74%, n = 428) decreased in HM groups compared to comparison groups. In a single trial, IL-1, IL-6, tumor necrosis factor (TNF)-a levels and the number of Tregs in the treatment group significantly decreased, while Th17 levels and the Th17/Treg ratios increased. Conclusion: This study provides a comprehensive and systematic review of the immunological effects of HM in patients with NSCLC. Future studies should explore how the immunological effects of HM correlate with clinical outcomes, such as tumor response and survival rates.PROSPERO registration: CRD42023459.