Feasibility of mesorectal vascular invasion in predicting early distant metastasis in patients with stage T3 rectal cancer based on rectal MRI

Abstract

OBJECTIVES: To evaluate the feasibility of mesorectal vascular invasion (MVI) in predicting early distant metastasis developed within 1 year of diagnosis of T3 rectal cancer using magnetic resonance imaging (MRI) METHODS: Sixty-five patients with T3 rectal cancer (early metastasis, n = 28: non-metastasis, n = 37) were enrolled in this study. Early distant metastases developed in 28 patients (liver, n = 15: lung, n = 9: both, n = 4). Logistic regression was used to determine the independent predictors for early distant metastasis. RESULTS: In univariate analysis, tumour location, carcinoembryonic antigen (CEA), lymphovascular invasion (LVI), MRI-detected MVI, and mesorectal fat infiltration (MFI) (odds ratio [OR], 4.533, 9.583, 5.539, 27.046, and 5.539, respectively) were associated with early distant metastasis. Multivariate analysis demonstrated that MVI (OR, 29.949: P < 0.002) and LVI (OR, 6.684: P = 0.033) were independent factors for early distant metastasis. Specificity and positive predictive value (PPV) of MVI (94.59%, and 89.47%, respectively) were significantly higher than those of LVI (64.86%, and 61.76%), but sensitivity and negative predictive value were not significantly different between MVI (60.71%, and 76.09%) and LVI (75.00%, and 77.42%). CONCLUSIONS: While sensitivity of MRI-detected MVI was equal to that of CEA in predicting early distant metastasis from T3 rectal cancer, specificity and PPV may be improved by assessing MVI. KEY POINTS: * Mesorectal vascular invasion (MVI) may be a radiologic prognostic factor for rectal cancer. * Specificity of MVI was higher than lymphovascular invasion in predicting early metastasis. * Mesorectal vascular invasion may be a better predictor for early distant metastasis.