Role of magnetic resonance imaging in loco-regional evaluation of cancer rectum, pre and post neoadjuvant therapy

The Diagnostic Performance of MRI for Detection of Extramural Venous Invasion in Colorectal Cancer: A Systematic Review and Meta-Analysis of the Literature

OBJECTIVE. The purpose of this article is to perform a systematic review and meta-analysis regarding the diagnostic test accuracy of MRI for detecting extramural venous invasion (EMVI) in patients with colorectal cancer. MATERIALS AND METHODS. PubMed and EMBASE were searched up to November 9, 2018. We included diagnostic accuracy studies that used MRI for EMVI detection in patients with colorectal cancer, using pathologic analysis as the reference standard. The methodologic quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Sensitivity and specificity were pooled and plotted in a hierarchic summary ROC plot. Metaregression analysis using several clinically relevant covariates was performed. RESULTS. Fourteen studies (n = 1751 patients) were included. Study quality was moderate in general. Pooled sensitivity was 0.61 (95% CI, 0.49-0.71), and pooled specificity was 0.87 (95% CI, 0.79-0.92). There was substantial heterogeneity according to the Cochran Q test (p < 0.01) and Higgins I² heterogeneity index (98% and 95% for sensitivity and specificity, respectively). Publication bias was present (p = 0.01). Higher rates of advanced T category, use of high-resolution MRI, and use of antispasmodic drugs were shown to significantly affect heterogeneity (p < 0.01). Location of primary tumor, preoperative treatment status, study design, definition of reference standard, magnetic field strength, and use of functional MRI were not statistically significant (p = 0.17-0.92). CONCLUSION. MRI shows moderate sensitivity and good specificity for the detection of EMVI in colorectal cancer. The use of high-resolution MRI may improve diagnostic performance.