A Nomogram Model For Predicting Risk Factors Of Low Anterior Resection Syndrome After Anus-preserving Radical Resection For Rectal Cancer

ObjectiveTo investigate the risk factors of postoperative low anterior resection syndrome in patients after anus-preserving radical resection for rectal cancer.A nomogram risk prediction model was established according to the selected risk factors,then the accuracy and prediction performance of the model were verified.MethodsThe clinical data of patients who underwent anterior resection or Dixon operation for rectal cancer and were discharged from the hospital between October 2019 and September 2020 in the General Department of the First Affiliated Hospital of Anhui Medical University were retrospectively analyzed.During the follow-up,according to the results of the LARS scale,the minor and major patients were divided into the LARS group,and the asymptomatic patients were divided into the non-LARS group.Theχ~2test was used to compare the clinical indicators between groups,and the indicators with statistically significant differences were subjected to multivariate logistic regression analysis to screen out independent risk factors for postoperative LARS.Finally,the nomogram risk prediction model was constructed by the program package in the R software,and the prediction performance and accuracy of the model were evaluated by the internal validation of the Bootstrap method and the area under the ROC curve（AUC）.ResultsA total of 214 patients met the inclusion criteria in this study,including 118 males and96 females,with an average age of 64.19±10.32 years（24-87 years old）.Patients who received adjuvant therapy after surgery were evaluated by the LARS scale at least two weeks after the end of the treatment to avoid the side effects of the treatment affecting their LARS score.A total of 99 patients（46.2%）suffered from postoperative LARS,including 59 patients（59.6%）who were minor,40 patients（40.4%）who were major,and 115 patients（53.7%）who did not suffer from postoperative LARS.The results of comprehensive univariate analysis and multivariate logistic regression analysis showed that BMI≥24kg·m^-2（OR=2.041,95%CI:1.038～4.013）、recovery time≤6months（OR=2.456,95%CI:1.339～4.505）、the distance from tumor to anus≤7cm（OR=2.735,95CI%:1.480～5.055）、neoadjuvant therapy（OR=3.772,95CI%:1.109～12.832）、anastomotic leak（OR=5.537,95CI%:1.103～27.791）were independent risk factors of LARS.Based on the 5 selected risk factors,a nomogram model was established to predict the risk factors of LARS after anus-preserving radical resection for rectal cancer.The area under ROC curve of the nomogram model was 0.754（95%CI:0.689～0.819）.After internal verification by Bootstrap self-sampling method,the C-index value of the model was 0.750 and the calibration curve fitted well with the ideal curve.ConclusionThe risk model constructed based on five risk factors has a good predictive ability for the incidence of LARS in patients with rectal cancer after anus-preserving radical resection,which is helpful to identify high-risk groups early and formulate corresponding clinical intervention measures.