Abstract:Objective To evaluate the preoperative predictive performance of the model based on magnetic resonance imaging (MRI) features and tumor markers for extramural vascular invasion (EMVI) in rectal cancer.Methods The 107 patients with rectal cancer admitted to our hospital from January 2021 to January 2024 were selected. All patients underwent pathological examination and MRI scans, and were divided into negative group and positive group according to the occurrence of EMVI. The clinical data, MRI features and tumor markers were compared between the positive group and the negative group, and the influencing factors for EMVI in rectal cancer were analyzed. The predictive value of the Logistic regression model based on MRI features combined with tumor markers for EMVI in rectal cancer was assessed.Results Among the 107 patients with rectal cancer, 34 cases developed EMVI. There was no difference in age, family history of rectal cancer, sex composition, degree of tumor differentiation and body mass index (BMI) between the two groups (P > 0.05). The proportion of stage T3 and T4 tumors, the rate of positive circumferential resection margin, and the proportion of MRI-detected EMVI (mrEMVI) score > 2 in the positive group were all higher than those in the negative group (P < 0.05). The serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 199 (CA199) in the positive group were higher than those in the negative group (P < 0.05). Multivariable Logistic regression analysis showed that the T stage [O^R= 5.703 (95% CI: 2.507, 12.973) ], circumferential resection margin [O^R = 3.554 (95% CI: 1.562, 8.084) ], mrEMVI scores [O^R =3.777 (95% CI: 1.660, 8.593) ], and serum levels of CEA [O^R = 4.104 (95% CI: 1.804, 9.336) ] and CA199 [O^R = 4.559 (95% CI: 2.004, 10.370) ] were factors affecting the occurrence of EMVI in rectal cancer (P < 0.05). The Logistic regression model was constructed based on MRI features and tumor markers as Log (P) = -4.573 + 1.741 × T stage + 1.268 × circumferential resection margin + 1.329 × mrEMVI score + 1.412 × serum CEA + 1.517 × serum CA199 and was well-fitted (P < 0.05). The receiver operating characteristic (ROC) curve analysis showed that the sensitivity of the regression model in predicting EMVI in rectal cancer before surgery was 91.18% (95% CI: 0.752, 0.977), with a specificity of 89.04% (95% CI: 0.790, 0.948), and an area under the curve of 0.912 (95% CI: 0.857, 0.964) (P < 0.05).Conclusion The Logistic regression model based on the T stage, circumferential resection margin, mrEMVI scores, and serum levels of CEA and CA199 is of great value for preoperative prediction of EMVI in rectal cancer.