Impact of laparoscopic versus open surgery on humoral immunity in patients with colorectal cancer: a systematic review and meta-analysis

Background: Laparoscopic surgery (LS) is hypothesized to result in milder proinfammatory reactions due to less severe operative trauma, which may contribute to the observed clinical benefts after LS. However, previous systematic reviews and meta-analyses on the impact of LS on immunocompetence are outdated, limited and heterogeneous. Therefore, the humoral response after laparoscopic and open colorectal cancer (CRC) resections was evaluated in a comprehensive systematic review and meta-analysis. Methods: Included were randomized controlled trials (RCTs) measuring parameters of humoral immunity after LS compared to open surgery (OS) in adult patients with CRC of any stage. MEDLINE, Embase, Web of Science (SCI-EXPANDED), Cochrane Library, Google Scholar, ClinicalTrials.gov and ICTRP (World Health Organization) were systematically searched. Risk of bias (RoB) was assessed using the Cochrane RoB2 tool. Weighted inverse variance meta-analysis of mean diferences was performed for C-reactive protein (CRP), interleukin (IL)-6, IL-8, tumour necrosis factor (TNF)α and vascular endothelial growth factor (VEGF) using the random-efects method. Methods were prospectively registered in PROSPERO (CRD42021264324). Results: Twenty RCTs with 1131 participants were included. Narrative synthesis and meta-analysis up to 8 days after surgery was performed. Quantitative synthesis found concentrations to be signifcantly lower after LS at 0–2 h after surgery (IL-8), at 3–9 h (CRP, IL-6, IL-8, TNFα) and at postoperative day 1 (CRP, IL-6, IL-8, VEGF). At 3–9 h, IL-6 was notably lower in the LS group by 86.71 pg/ml (mean diference [MD] − 86.71 pg/ml [− 125.05, − 48.37], p