Association between preoperative respiratory function and postoperative complications in patients with colorectal cancer: a retrospective study

Purpose Postoperative pulmonary complications (PPCs) in patients with colorectal cancer worsen long-term survival, making preoperative prediction and prevention critically important. However, the association between the preoperative respiratory function and PPCs in colorectal cancer surgery remains unclear. This study aimed to clarify the association between respiratory function and the occurrence of PPCs after colorectal cancer surgery. Methods This retrospective study included patients who underwent colorectal cancer surgery and preoperative respiratory tests at Kanazawa University Hospital between November 2006 and May 2025. Normal respiratory function was defined as forced expiratory volume in one second/forced vital capacity ratio (FEV 1 /FVC) ≥ 70%, and low respiratory function was defined as FEV 1 /FVC < 70%. The primary outcome was PPC incidence, including pneumonia and atelectasis. We performed propensity score matching to adjust for patient backgrounds and used a logistic regression model to identify factors associated with PPCs. Statistical significance was set at P < 0.05. Results Of the 1164 patients, 839 (72.1%) had normal and 325 (27.9%) had low respiratory function. After matching, 166 patients were included in each group. No statistically significant difference in PPC incidence was found between the two groups (P = 0.283). In a multivariate analysis, low respiratory function was not a significant risk factor for PPCs (odds ratio: 1.070, 95% confidence interval: 0.448–2.540). Conclusion Preoperative respiratory function may not be associated with PPC incidence after colorectal cancer surgery. Large-scale, multicenter prospective studies are required to demonstrate the validity of the association between preoperative respiratory function and the incidence of PPCs.