Objective To investigate the key risk factors for low anterior resection syndrome (LARS) within 6 months after rectal cancer surgery and to construct a risk prediction model based on the random forest algorithm, providing a reference for early clinical intervention. Methods A retrospective study was conducted on patients who underwent rectal cancer surgery at West China Hospital of Sichuan University between January 2020 and August 2021. A total of 394 patients were included. A prediction model for the occurrence of LARS within 6 months after rectal cancer surgery was constructed using the random forest algorithm. The dataset was divided into a training set and a test set in an 8:2 ratio. Model performance was evaluated by accuracy, sensitivity, specificity, area under the receiver operating characteristic curve (AUC), Brier score, and decision curve analysis (DCA). The SHAP (Shapley Additive Explanations) method was used to interpret the contribution of each variable. Results Among the 394 patients, 106 developed LARS within 6 months after surgery, with an incidence rate of 26.9%. According to the importance ranking in the random forest algorithm, the key predictors were: distance from the inferior tumor margin to the dentate line, body mass index (BMI), tumor size, time to postoperative flatus, operation time, age, neoadjuvant therapy, and TNM stage. The prediction model built using these key factors achieved an accuracy of 73.4%, sensitivity of 75.0%, specificity of 72.7%, AUC (95% confidence interval) of 0.801 (0.685, 0.916), and a Brier score of 0.198. DCA showed that the model provided favorable clinical benefit when the threshold probability was between 25% and 64%. Conclusion The results of this study suggest that patients with a shorter distance from the tumor to the dentate line, higher BMI, larger tumor size, and those receiving neoadjuvant therapy are at higher risk of developing LARS. The risk prediction model constructed in this study demonstrated good predictive performance and may provide a useful reference for early identification of high-risk patients after rectal cancer surgery.
ObjectiveTo understand the impact of preoperative nutritional status on the postoperative complications for patients with low/ultra-low rectal cancer undergoing extreme sphincter-preserving surgery following neoadjuvant therapy. MethodsThe patients with low/ultra-low rectal cancer who underwent extreme sphincter-preserving surgery following neoadjuvant therapy from January 2009 to December 2020 were retrospectively collected using the Database from Colorectal Cancer (DACCA), and then who were assigned into a nutritional risk group (the score was low than 3 by the Nutrition Risk Screening 2002) and non-nutritional risk group (the score was 3 or more by the Nutrition Risk Screening 2002). The postoperative complications and survival were analyzed for the patients with or without nutritional risk. The postoperative complications were defined as early-term (complications occurring within 30 d after surgery), middle-term (complications occurring during 30–180 d after surgery), and long-term (complications occurring at 180 d and more after surgery). The survival indicators included overall survival and disease-specific survival. ResultsA total of 680 patients who met the inclusion criteria for this study were retrieved from the DACCA database. Among them, there were 500 (73.5%) patients without nutritional risk and 180 (26.5%) patients with nutritional risk. The postoperative follow-up time was 0–152 months (with average 48.9 months). Five hundreds and forty-three survived, including 471 (86.7%) patients with free-tumors survival and 72 (13.3%) patients with tumors survival. There were 137 deaths, including 122 (89.1%) patients with cancer related deaths and 15 (10.9%) patients with non-cancer related deaths. There were 48 (7.1%) cases of early-term postoperative complications, 51 (7.5%) cases of middle-term complications, and 17 (2.5%) cases of long-term complications. There were no statistical differences in the incidence of overall complications between the patients with and without nutritional risk (χ2=3.749, P=0.053; χ2=2.205, P=0.138; χ2=310, P=0.578). The specific complications at different stages after surgery (excluding the anastomotic leakage complications in the patients with nutritional risk was higher in patients without nutritional risk, P=0.034) had no statistical differences between the two groups (P>0.05). The survival curves (overall survival and disease-specific survival) using the Kaplan-Meier method had no statistical differences between the patients with and without nutritional risk (χ2=3.316, P=0.069; χ2=3.712, P=0.054). ConclusionsFrom the analysis results of this study, for the rectal cancer patients who underwent extreme sphincter-preserving surgery following neoadjuvant therapy, the patients with preoperative nutritional risk are more prone to anastomotic leakage within 30 d after surgery. Although other postoperative complications and long-term survival outcomes have no statistical differences between patients with and without nutritional risk, preoperative nutritional management for them cannot be ignored.
ObjectiveTo analyze the impact of preoperative hypoproteinemia on postoperative complications in patients with rectal cancer based on the current version of the Database from Colorectal Cancer (DACCA). MethodsThe patient information was extracted from the updated version of DACCA in April 2024 according to predefined inclusion criteria. The preoperative hypoproteinemia and incidence of complications were analyzed. The univariate and multivariate logistic regression analyses were performed to identify risk factors for complications in three postoperative periods (in-hospital, short-term, and long-term). The test level was α=0.05. ResultsA total of 1 440 patients with rectal cancer were included, 322 (22.4%) with preoperative hypoproteinemia and 1 118 (77.6%) without. Compared to the patients without preoperative hypoproteinemia, those with preoperative hypoproteinemia were older (P<0.001), had a lower body mass index (P<0.001), smaller tumor margins (P=0.032), and a higher proportion of patients with pTNM stage Ⅳ (P<0.001). There were no statistically significant differences in the overall incidence of complications during the three postoperative periods (in-hospital, short-term, and long-term) between the patients with and without preoperative hypoproteinemia (χ2=0.399, P=0.280; χ2=0.298, P=0.585; χ2=1.416, P=0.234). Except for urinary retention, there were no significant differences in the incidence of specific complications between the two groups (P>0.05). The univariate and multivariate logistic regression analyses did not identify preoperative hypoproteinemia as a risk factor for postoperative complications (P>0.05). ConclusionsThe results of this study suggest that the incidence of preoperative hypoproteinemia is higher in patients with rectal cancer. Patients with preoperative hypoproteinemia tend to be older, have a lower body mass index, and a higher proportion of pTNM stage Ⅳ. However, it was not found that preoperative hypoproteinemia is a risk factor for postoperative complications.