Abstract
BACKGROUND: Progress in the use of neoadjuvant immunotherapy combined with chemotherapy has become a highlight of cancer research. Our meta-analysis aimed to better elucidate the activity, efficacy and safety of this combination using data obtained from randomized controlled trials (RCTs). METHODS: A systematic search of PubMed, Embase, Web of Science, the Cochrane Library and conference proceedings up to January 31, 2023 was carried out to identify RCTs investigating neoadjuvant immunotherapy combined with chemotherapy for the treatment of solid tumors. Using fixed- and random-effects models, pooled odds ratios (ORs) and hazard ratios with 95% confidence intervals (CIs) were calculated for pathological complete response (pCR, defined as ypT0/is pN0) and immunotherapy treatment-related adverse events. RESULTS: A total of 1876 studies were identified, and 6 RCTs (N = 2558 patients) were included. The pCR was significantly higher with neoadjuvant immunotherapy combined with chemotherapy than with neoadjuvant chemotherapy alone (OR = 2.30, 95% CI: 1.43-3.71, P < .001). The pCR was confirmed to be statistically significant in the PD-L1-positive subgroup (OR = 2.01; 95% CI: 1.55-2.59, P = .012). The pCR was confirmed to be statistically significant in the PD-1 inhibitor subgroup (OR = 4.17; 95% CI: 1.47-11.87, P = .000), while no statistically significant was observed in the PD-L1 inhibitor subgroup (OR = 1.52; 95% CI: 1.12-2.07, P = .308). The pooled ORs of any grade treatment-related or immunotherapy-related adverse events were significant, but the grade 3-4 immunotherapy-related adverse events were not. CONCLUSION: Our study provides comprehensive data that the addition of PD1 blockade to neoadjuvant chemotherapy resulted in better treatment efficacy than neoadjuvant chemotherapy alone in patients with solid tumors and had a similar safety profile.