Peritoneal cytokines as a predictor of colorectal anastomotic leaks on postoperative day 1: a systematic review and meta-analysis.

Background: Anastomotic leakage (AL) is a major complication of colorectal surgery resulting in morbidity, mortality and poorer quality of life. The early diagnosis of AL is challenging due to the poor positive predictive value of tests available and reliance on clinical presentation which may be delayed. The aim of this systematic review was to assess the applicability of peritoneal cytokine levels as an early predictive test of AL in postoperative colorectal cancer patients. Methods: A comprehensive literature search was performed from inception to January 2021, in MEDLINE and EMBASE databases using MeSH and non-MeSH terms in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies evaluating peritoneal cytokines in the context of AL were included in this review. Results: Two hundred ninety-two abstracts were screened, 30 full manuscripts evaluated, and 12 prospective studies were included. There were 8 peritoneal cytokines evaluated (interleukin [IL]-1β, IL-6, IL-8, IL-10, vascular endothelial growth factor [VEGF], tumour necrosis factor alpha [TNF alpha] and matrix metalloproteinase [MMP]2 and MMP9) between AL and non-AL groups on postoperative day 1. Those that included IL-6 (7 studies), IL-10 (4 studies), TNF alpha (6 studies) and MMP9 (2 studies) were included in the meta-analysis. IL-10 was the only cytokine in the meta-analysis that was significantly (p < 0.05) raised in drain fluid on postoperative day 1 in AL patients. Conclusions: Peritoneal IL-10 was significantly raised on postoperative day 1 in patients who subsequently developed AL. This may be a useful early predictor of AL and aid in an earlier diagnosis for postoperative colorectal patients. The range of cytokines investigated within the literature is limited and from heterogeneous studies which suggests more research is needed. [ABSTRACT FROM AUTHOR]