Accuracy of Contrast-Enhanced Mammography (CEM) Compared With Breast MRI in Detecting Residual Disease After Neoadjuvant Therapy: A Systematic Review.

Accurate assessment of residual tumor burden following neoadjuvant therapy (NAT) is critical for predicting patient outcomes and guiding surgical decision-making in breast cancer management. While breast MRI remains the reference standard for posttreatment evaluation, contrast-enhanced mammography (CEM) has emerged as a promising alternative because MRI is often limited by its high cost, limited accessibility, prolonged examination time, and contraindications in certain patient populations. This study aims to evaluate the diagnostic precision of breast MRI and CEM in identifying residual disease in patients with breast cancer following neoadjuvant treatment. Using PubMed/MEDLINE, Embase, Cochrane CENTRAL, and Web of Science, a systematic review was carried out between January 2021 and January 2026 in accordance with the PRISMA standards. Included studies were prospective or retrospective head-to-head comparative studies reporting sufficient information to create 2 × 2 contingency tables for precise diagnosis, with histopathology as the reference standard. Six studies met the eligibility criteria, comprising 349 participants. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool was used to assess quality. MRI sensitivity varied from 44.4% to 100%, whereas CEM sensitivity ranged from 77.8% to 100%. MRI specificity varied from 47% to 94.4%, whereas CEM specificity ranged from 50% to 83.3%. CEM demonstrated a tendency toward higher sensitivity but lower specificity compared with MRI. The remaining tumor size was consistently overestimated by both modalities by approximately 1-3 mm. False-negative rates were notably low for CEM (0-22.2%) but reached 55.6% for MRI in one small study. Identification of residual ductal carcinoma in situ remained challenging for both techniques, with improved detection when incorporating mammographic calcification assessment. The QUADAS-2 assessment indicated a low risk of bias for most studies. When identifying residual disease following neoadjuvant treatment, CEM and MRI exhibit similar diagnostic accuracy, with MRI having better specificity and CEM having higher sensitivity. When MRI is unavailable or contraindicated, CEM is a dependable substitute because of its practical benefits, which include reduced cost, shorter examination times, greater availability, and the lack of gadolinium-related contraindications. Tumor subtype, patient features, and institutional resources should all be taken into consideration when selecting a modality.