Diagnostic Performance of MRI and FDG PET/CT for Preoperative Locoregional Staging of Colon Cancer: Systematic Review and Meta-Analysis

BACKGROUND. CT is the standard-of-care test for preoperative locoregional staging of colon cancer (CC) but has limited diagnostic performance. More accurate preoperative staging would guide selection among expanding patient-tailored treatment options. OBJECTIVE. The purpose of this study was to evaluate through systematic review the diagnostic performance of MRI for T and N staging and that of FDG PET/CT for N staging in the locoregional staging of CC. EVIDENCE ACQUISITION. PubMed, Embase, and the Cochrane Library were searched through December 31, 2023, for studies reporting the diagnostic performance of MRI or FDG PET/CT for primary (nonrectal) CC before resection without neoadjuvant therapy, with histopathology used as the reference standard. Study quality was assessed using the QUADAS-2 tool. Publication bias was assessed using the Deeks funnel plot asymmetry test. Primary outcomes were estimated pooled predictive values, which were stratified by T and N categories for MRI and by N categories for PET/CT. Secondary outcomes were pooled sensitivity and specificity. EVIDENCE SYNTHESIS. The systematic review included 11 MRI studies (686 patients) and five PET/CT studies (408 patients). Thirteen studies had at least one risk of bias or concern of applicability. The Deek funnel plot asymmetry test indicated possible publication bias in MRI studies for differentiation of T3cd-T4 disease from T1-T3ab disease and differentiation of node-negative disease from node-positive disease. For MRI, for discriminating T1-T2 from T3-T4 disease, PPV was 64.8% (95% CI, 52.9-75.5%) and NPV was 88.9% (95% CI, 82.7-93.7%); for discriminating T1-T3ab from T3cd-T4 disease, PPV was 83.4% (95% CI, 75.0-90.3%) and NPV was 74.6% (95% CI, 58.2-86.7%); for discriminating T1-T3 from T4 disease, PPV was 94.0% (95% CI, 89.4-97.3%) and NPV was 39.9% (95% CI, 24.9-56.6%); for discriminating node-negative from node-positive disease, PPV was 74.9% (95% CI, 69.3-80.0%) and NPV was 53.9% (95% CI, 45.3-62.0%). For PET/CT, for discriminating node-negative from node-positive disease, PPV was 76.4% (95% CI, 67.9-85.1%) and NPV was 68.2% (95% CI, 56.8-78.6%). Across outcomes, MRI and PET/CT showed pooled sensitivity of 55.1-81.4% and pooled specificity of 70.3-88.1%. CONCLUSION. MRI had the strongest predictive performance for T1-T2 and T4 disease. MRI and PET/CT otherwise had limited predictive values, sensitivity, and specificity for evaluated outcomes related to T and N staging. CLINICAL IMPACT. MRI and FDG PET/CT had overall limited utility for preoperative locoregional staging of colon cancer. TRIAL REGISTRATION. PROSPERO (International Prospective Register of Systematic Reviews) CRD42022326887.