Meta-analysis of the clinicopathological characteristics and peri-operative outcomes of colorectal cancer in obese patients

•Obesity may contribute to worse outcomes in for CRC surgery.•Meta-analysis of 56,293 patients comparing outcomes dependent on BMI.•Obese patients are more likely to have lymph node metastases.•Obesity leads to reduced lymph node yield and more challenging resections.•There are no differences in length of stay dependent on BMI. The effect of obesity on the clinicopathological characteristics of colorectal cancer (CRC) has not been clearly characterized. This meta-analysis assesses the pathological and perioperative outcomes of obese patients undergoing surgical resection for CRC. Meta-analysis was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Databases were searched for studies reporting outcomes for obese and non-obese patients undergoing primary CRC resection, based on body-mass index measurement. Results were reported as mean differences or pooled odds ratios (OR) with 95% confidence intervals (95% CI). A total of 2183 citations were reviewed; 29 studies comprising 56,293 patients were ultimately included in the analysis, with an obesity rate of 19.3%. Obese patients with colorectal cancer were more often female (OR 1.2, 95% CI 1.1–1.2, p