Sex-related effects on postoperative mortality after colorectal cancer surgery: a systematic review and meta-analysis

Background: The patient’s sex is an important factor affecting postoperative mortality following colorectal cancer surgery; however, this relationship is not fully understood. Methods: We searched for eligible studies evaluating the relationship between sex and postoperative mortality in patients undergoing colorectal cancer surgery. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random-effects models. Subgroup and sensitivity analyses were performed to assess the stability of the main findings. Results: Sixty-four studies involving 3,364,109 participants were included. Male patients had a 22% higher risk of postoperative mortality compared with female patients (OR: 1.22, 95% CI: 1.17–1.28). This finding remained consistent and stable in most subgroup analyses, with a more significant relationship in studies with adjusted ORs (OR: 1.25, 95% CI: 1.19–1.31). Sensitivity analyses confirmed these findings, with male patients consistently showing a 23%–25% higher risk than female patients in various populations. The results were validated in sensitivity analyses using the leave-one-out method. Conclusion: In summary, male sex is significantly linked to an elevated risk of postoperative mortality after colorectal cancer surgery compared with female patients. Further investigations are needed to address the observed heterogeneities across studies and to explore the fundamental mechanisms underlying these sex-related differences.