Diagnostic Accuracy of MRI for Assessment of T-category, Lymph Node Metastases, and Circumferential Resection Margin Involvement in Patients with Rectal Cancer: A Systematic Review and Meta-analysis

BACKGROUND: MRI is increasingly being used for rectal cancer staging. The purpose of this study was to summarize published evidence to determine the accuracy of MRI for T-category, lymph node (LN) metastases, and circumferential resection margin (CRM) involvement in rectal cancer. METHODS: Sensitivity, specificity, and diagnostic odds ratios (DOR) were estimated using hierarchical summary receiver operating characteristics modeling and bivariate random effects modeling. RESULTS: MRI was more specific for CRM (94%, 95%CI 88-97) than for T-category (75%, 95%CI 68-80) and LN’s (71%, 95%CI 59-81) but was more sensitive for T-category (87%, 95%CI 81-92) than for CRM (77%, 95%CI 57-90) and LN’s (77%, 95%CI 69-84). DOR was higher for CRM (56.1, 95%CI 15.3-205.8) than for LN’s (8.3, 95%CI 4.6-14.7) and T-category (20.4, 95%CI 11.1-37.3). CONCLUSIONS: MRI has good accuracy for both CRM and T-category and should be considered for preoperative rectal cancer staging. In contrast, LN assessment is poor on MRI.MAS