Magnetic resonance imaging (MRI) was found to provide the most concordant tumor size assessment among breast imaging techniques, although significant overestimation exists, according to research presented at the 17th St. Gallen International Breast Cancer Conference 2021.F.C. Pop, from the Jules Bordet Institute, Université Libre de Bruxelles, in Brussels, Belgium, and colleagues included 752 patients (mean age, 61.8 years; range, 26.9-89.5) who had undergone primary surgery for unifocal invasive breast cancer. Participants also had complete documentation of the tumor size obtained via mammography, ultrasonography, and MRI. The researchers aimed to evaluate which preoperative breast imaging technique could more accurately determine tumor size in early breast cancer for different intrinsic tumor subtypes by comparing concordance, underestimation, and overestimation with use of the chi-square test. The study authors analyzed 757 breast cancer tumors: 419 (55.4%) luminal A, 262 (34.6%) luminal B, 56 (7.4%) triple negative, and 20 (2.6%) HER2 enriched. The mean (SD) tumor size was 15.2 (8.3) mm, and the size varied by imaging method: 13.7 (7.3) mm for mammography, 13.1 (7.4) mm for ultrasound, and 16.4 (9.1) mm for MRI.
