Abstract
Objective: This study aimed to compare the concordance of abbreviated MRI (AB-MRI) and full diagnostic protocol MRI (FDP-MRI) with pathology in assessing tumor extent for surgical planning in patients with newly diagnosed breast cancer. Additionally, we evaluated the performance of AB-MRI and FDP-MRI in detecting additional malignant lesions in the ipsilateral breast. Materials and Methods: A total of 319 patients with 330 index breast cancers were enrolled in the study. Two radiologists independently assessed tumor extent on AB-MRI and FDP-MRI and compared their measurements with the pathological tumor extent. For both MRI protocols, concordance rates and agreement of tumor extent with pathology were analyzed according to histopathologic and molecular subtypes using the chi-square test and ICC. Additional malignant lesions detection rates in the ipsilateral breast were compared between the two MRI protocols. Results: The mean total pathologic tumor extent, including the in situ component and adjacent malignant lesions, was 2.2 cm (standard deviation [SD]: 1.3 cm; range: 0.7-8.5 cm). The concordance rate of tumor extent with pathology between the two MRI protocols (AB- and FDP-MRI) showed no significant difference (reader 1, p = 0.68; reader 2, p = 0.74). The agreement of tumor extent with pathology was not significantly different between the two MRI protocols (AB-MRI and FDP-MRI: K = 0.70, 0.75, p = 0.17 in reader 1; K = 0.65, 0.71, p = 0.15 in reader 2). The detection rate of additional malignant lesions showed no significant difference between AB-MRI and FDP-MRI (p = 0.71 in reader 1, p = 0.89 in reader 2). Conclusions: AB-MRI is comparable to FDP-MRI for assessing tumor extent and detecting additional malignant lesions.