Preoperative contrast-enhanced CT for predicting t stage and lymph node metastasis in rectal cancer

YU Jingzhou; REN Shuai; YU Jie; SHAN Hua; WANG Yanling; CHU Lingling

doi:10.3969/j.issn.1674-4136.2026.01.008

Abstract：Objective To evaluate the clinical value of preoperative contrast-enhanced computed tomography(CT)in assessing T stage and regional lymph node metastasis in rectal cancer,and to provide reliable imaging evidence for individualized treatment strategies.Methods A total of 196 patients who underwent both non-contrast and contrast-enhanced CT scans at Jiangsu Province Hospital of Traditional Chinese Medicine between December 2019 and December 2023,and were pathologically confirmed to have rectal cancer postoperatively,were retrospectively included.Clinical data and preoperative contrast-enhanced CT images were collected.Imaging features such as degree of enhancement,tumor margins,morphology,and changes in perirectal fat planes were assessed.T and N stage were determined according to the 8th edition of the AJCC TNM classification.Postoperative pathological staging served as the reference standard.The diagnostic accuracy,sensitivity,specificity,positive predictive value(PPV),and negative predictive value(NPV)of CT in T and N stage were calculated.Results The accuracy of contrast-enhanced CT for T1-2,T3,and T4 stages was 82.69％,86.86％,and 85.71％,respectively,with an overall T stage accuracy of 85.71％.CT demonstrated the highest positive predictive value for T3 tumors(92.25％),the greatest sensitivity for T1-2 stages(90.28％),and a high NPV for T4 stage(99.42％).For N stage,the diagnostic accuracy for N0,N1,and N2 stages was 81.37％,63.64％,and 71.43％,respectively,with an overall accuracy of 73.98％.The specificity and NPV for N0 staging were relatively high(91.91％and 80.21％,respectively),while the PPV for N2 stage was relatively low(60.61％).The degree of enhancement showed a certain correlation with T and N stages,with moderate to marked enhancement more frequently observed in tumors staged T3 or higher.Conclusions Preoperative contrast-enhanced CT demonstrates high accuracy and clinical utility in the assessment of T stage and lymph node metastasis in rectal cancer.It provides important preoperative imaging information to guide the development of appropriate treatment strategies.